Three Dialogues between Hylas and Philonous
in opposition to Sceptics and Atheists

George Berkeley

Copyright copyright2010–2015 All rights reserved. Jonathan Bennett

[Brackets] enclose editorial explanations. Small dots enclose material that has been added, but can be read as though it were part of the original text. Occasional bullets, and also indenting of passages that are not quotations, are meant as aids to grasping the structure of a sentence or a thought.

First launched: July 2004 Last amended: November 2007

Contents

The First Dialogue
The Second Dialogue
The Third Dialogue

The First Dialogue

Philonous: Good morning, Hylas: I didn’t expect to find you out and about so early.

Hylas: It is indeed somewhat unusual: but my thoughts were so taken up with a subject I was talking about last night that I couldn’t sleep, so I decided to get up and walk in the garden.

Phil: That’s good! It gives you a chance to see what innocent and agreeable pleasures you lose every morning. Can there be a pleasanter time of the day, or a more delightful season of the year? That purple sky, those wild but sweet notes of birds, the fragrant bloom on the trees and flowers, the gentle influence of the rising sun, these and a thousand nameless beauties of nature inspire the soul with secret raptures. But I’m afraid I am interrupting your thoughts; for you seemed very intent on something.

Hyl: Yes, I was, and I’d be grateful if you would allow me to carry on with it. But I don’t in the least want to deprive myself of your company, for my thoughts always flow more easily in conversation with a friend than when I am alone. Please, may I share with you the thoughts I have been having?

Phil: With all my heart! It is what I would have requested myself, if you hadn’t asked first.

Hyl: I was considering the odd fate of those men who have in all ages, through a desire to mark themselves off from the common people or through heaven knows what trick of their thought, claimed either to believe nothing at all or to believe the most extravagant things in the world. This wouldn’t matter so much if their paradoxes and scepticism didn’t bring consequences that are bad for mankind in general. But there’s a risk that they will do that, and that when men who are thought to have spent their whole time in the pursuit of knowledge claim to be entirely ignorant of everything, or advocate views that are in conflict with plain and commonly accepted principles, this will tempt other people—who have less leisure for this sort of thing—to become suspicious of the most important truths, ones they had previously thought to be sacred and unquestionable.

Phil: I entirely agree with you about the bad effects of the paraded doubts of some philosophers and the fantastical views of others. I have felt this so strongly in recent times that I have dropped some of the high-flown theories I had learned in their universities, replacing them with ordinary common opinions. Since this revolt of mine against metaphysical notions and in favour of the plain dictates of nature and common sense, I swear that I find I can think ever so much better, so that I can now easily understand many things which previously were mysteries and riddles.

Hyl: I am glad to find there was nothing in the accounts I heard of you.

Phil: What, if you please, were they?

Hyl: In last night’s conversation you were represented as someone who maintains the most extravagant opinion that ever entered into the mind of man, namely that there is no such thing as material substance in the world.

Phil: I seriously believe that there is no such thing as what philosophers call ‘material substance’; but if I were made to see anything absurd or sceptical in this, then I would have the same reason to renounce this belief as I think I have now to reject the contrary opinion.

Hyl: What! can anything be more fantastical, more in conflict with common sense, or a more obvious piece of scepticism, than to believe there is no such thing as matter?

Phil: Steady on, Hylas! What if it were to turn out that you who hold that there is matter are—by virtue of that opinion—a greater sceptic, and maintain more paradoxes and conflicts with common sense, than I who believe no such thing?

Hyl: You have as good a chance of convincing me that the part is greater than the whole as of convincing me that I must give up my belief in matter if I am to avoid absurdity and scepticism.

Phil: Well then, are you content to accept as true any opinion that turns out to be the most agreeable to common sense, and most remote from scepticism?

Hyl: With all my heart. Since you want to start arguments about the plainest things in the world, I am content for once to hear what you have to say.

Phil: Tell me, please, Hylas: what do you mean by a ‘sceptic’?

Hyl: I mean what everyone means, ‘someone who doubts everything’.

Phil: So if someone has no doubts concerning some particular point, then with regard to that point he cannot be thought a sceptic.

Hyl: I agree with you.

Phil: Does doubting consist in accepting the affirmative or the negative side of a question?

Hyl: Neither. Anyone who understands English must know that doubting signifies a suspense between the two sides.

Phil: So if someone denies any point, he can no more be said to doubt concerning it than he who affirms it with the same degree of assurance.

Hyl: True.

Phil: And so his denial no more makes him a sceptic than the other is.

Hyl: I acknowledge it.

Phil: Then how does it happen, Hylas, that you call me a sceptic because I deny what you affirm, namely the existence of matter? For all you know, I may be as firmly convinced in my denial as you are in your affirmation.

Hyl: Hold on a moment, Philonous. My definition of ‘sceptic’ was wrong; but you can’t hold a man to every false step he makes in conversation. I did say that a sceptic is someone who doubts everything; but I should have added, ‘…or who denies the reality and truth of things’.

Phil: What things? Do you mean the principles and theorems of sciences? But these, you know, are universal intellectual notions, and have nothing to do with matter, so that the denial of matter doesn’t imply the denial of them.

Hyl: I agree about that. But what about other things? What do you think about distrusting the senses, denying the real existence of sensible things, or claiming to know nothing of them? Isn’t that enough to qualify a man as a sceptic? [Throughout the Dialogues, ‘sensible’ means ‘capable of being sensed’—that is, visible or audible or tangible etc.]

Phil: Well, then, let us see which of us it is that denies the reality of sensible things, or claims to have the greatest ignorance of them; since, if I understand you rightly, he is to be counted the greater sceptic.

Hyl: That is what I desire.

Phil: What do you mean by ‘sensible things’?

Hyl: Things that are perceived by the senses. Can you imagine that I mean anything else?

Phil: I’m sorry, but it may greatly shorten our enquiry if I have a clear grasp of your notions. Bear with me, then, while I ask you this further question. Are things ‘perceived by the senses’ only the ones that are perceived immediately? Or do they include things that are perceived mediately, that is, through the intervention of something else?

Hyl: I don’t properly understand you.

Phil: In reading a book, what I immediately perceive are the letters on the page, but mediately or by means of these the notions of God, virtue, truth, etc. are suggested to my mind. Now, there’s no doubt that the letters are truly sensible things, or things perceived by sense; but I want to know whether you take the things suggested by them to be ‘perceived by sense’ too.

Hyl: No, certainly, it would be absurd to think that God or virtue are sensible things, though they may be signified and suggested to the mind by sensible marks with which they have an arbitrary connection.

Phil: It seems then, that by ‘sensible things’ you mean only those that can be perceived immediately by sense.

Hyl: Right.

Phil: Doesn’t it follow from this that when I see one part of the sky red and another blue, and I infer from this that there must be some cause for that difference of colours, that cause cannot be said to be a ‘sensible thing’ or perceived by eyesight?

Hyl: It does.

Phil: Similarly, when I hear a variety of sounds I cannot be said to hear their causes.

Hyl: You cannot.

Phil: And when by touch I feel a thing to be hot and heavy, I can’t say with any truth or correctness that I feel the cause of its heat or weight.

Hyl: To head off any more questions of this kind, I tell you once and for all that by ‘sensible things’ I mean only things that are perceived by sense, and that the senses perceive only what they perceive immediately; because they don’t make inferences. So the deducing of causes or occasions from effects and appearances (which are the only things we perceive by sense) is entirely the business of reason. [In this context, ‘occasion’ can be taken as equivalent to ‘cause’. The two terms are separated in the Second Dialogue at page 46.]

Phil: We agree, then, that sensible things include only things that are immediately perceived by sense. Now tell me whether we immediately perceive

by sight anything besides light, colours, and shapes;

by hearing anything but sounds;

by the palate anything besides tastes;

by the sense of smell anything besides odours;

by touch anything more than tangible qualities.

Hyl: We do not.

Phil: So it seems that if you take away all sensible qualities there is nothing left that is sensible.

Hyl: I agree.

Phil: Sensible things, then, are nothing but so many sensible qualities, or combinations of sensible qualities.

Hyl: Nothing else.

Phil: So heat is a sensible thing.

Hyl: Certainly.

Phil: Does the reality of sensible things consist in being perceived? or is it something different from their being perceived—something that doesn’t involve the mind?

Hyl: To exist is one thing, and to be perceived is another.

Phil: I am talking only about sensible things. My question is: By the ‘real existence’ of one of them do you mean an existence exterior to the mind and distinct from their being perceived?

Hyl: I mean a real absolute existence—distinct from, and having no relation to, their being perceived.

Phil: So if heat is granted to have a real existence, it must exist outside the mind.

Hyl: It must.

Phil: Tell me, Hylas, is this real existence equally possible for all degrees of heat that we feel; or is there a reason why we should attribute it to some degrees of heat and not to others? If there is, please tell me what it is.

Hyl: Whatever degree of heat we perceive by sense we can be sure exists also in the object that occasions it.

Phil: What, the greatest as well as the least?

Hyl: Yes, because the same reason holds for both: they are both perceived by sense; indeed, the greater degree of heat is more intensely sensibly perceived; so if there is any difference it is that we are more certain of the real existence of a greater heat than we can be of the reality of a lesser.

Phil: But isn’t the most fierce and intense degree of heat a very great pain?

Hyl: No-one can deny that.

Phil: And can any unperceiving thing have pain or pleasure?

Hyl: Certainly not.

Phil: Is your material substance a senseless thing or does it have sense and perception?

Hyl: It is senseless, without doubt.

Phil: So it can’t be the subject of pain.

Hyl: Indeed it can’t.

Phil: Nor, consequently, can it be the subject of the greatest heat perceived by sense, since you agree that this is a considerable pain.

Hyl: I accept that.

Phil: Then what are we to say about your external object? Is it a material substance, or is it not?

Hyl: It is a material substance with the sensible qualities inhering in it.

Phil: But then how can a great heat exist in it, since you agree it cannot exist in a material substance? Please clear up this point.

Hyl: Hold on, Philonous! I’m afraid I went wrong in granting that intense heat is a pain. I should have said not that the pain is the heat but that it is the consequence or effect of the heat.

Phil: When you put your hand near the fire, do you feel one simple uniform sensation or two distinct sensations?

Hyl: Just one simple sensation.

Phil: Isn’t the heat immediately perceived?

Hyl: It is.

Phil: And the pain?

Hyl: True.

Phil: Well, then, seeing that they are both immediately perceived at the same time, and that the fire affects you with only one simple or uncompounded idea [= one idea without parts], it follows that this one simple idea is both the immediately perceived intense heat and the pain; and consequently, that the immediately perceived intense heat is identical with a particular sort of pain.

Hyl: It seems so.

Phil: Consult your thoughts again, Hylas: can you conceive an intense sensation to occur without pain or pleasure?

Hyl: I cannot.

Phil: Or can you form an idea of sensible pain or pleasure in general, abstracted from every particular idea of heat, cold, tastes, smells, etc.?

Hyl: I don’t find that I can.

Phil: Then doesn’t it follow that sensible pain is nothing but intense degrees of those sensations or ideas?

Hyl: That is undeniable. In fact, I’m starting to suspect that a very great heat can’t exist except in a mind perceiving it.

Phil: What! are you then in that sceptical state of suspense, between affirming and denying?

Hyl: I think I can be definite about it. A very violent and painful heat can’t exist outside the mind.

Phil: So according to you it has no real existence.

Hyl: I admit it.

Phil: Is it certain, then, that no body in nature is really hot?

Hyl: I haven’t said that there is no real heat in bodies. I only say that there’s no such thing as an intense real heat in bodies.

Phil: But didn’t you say earlier that all degrees of heat are equally real, or that if there is any difference the greater heat is more certainly real than the lesser?

Hyl: Yes, I did; but that was because I had overlooked the reason there is for distinguishing between them, which I now plainly see. It is this: because intense heat is nothing but a particular kind of painful sensation, and pain can’t exist except in a perceiving being, it follows that no intense heat can really exist in an unperceiving corporeal [= ‘bodily’] substance. But that’s no reason for denying that less intense heat can exist in such a substance.

Phil: But how are we to draw the line separating degrees of heat that exist only in the mind from ones that exist outside it?

Hyl: That isn’t hard. The slightest pain can’t exist unperceived, as you know; so any degree of heat that is a pain exists only in the mind. We don’t have to think the same for degrees of heat that are not pains.

Phil: I think you agreed a while back that no unperceiving being is capable of pleasure, any more than it is of pain.

Hyl: I did.

Phil: Well, isn’t warmth—a milder degree of heat than what causes discomfort or worse—a pleasure?

Hyl: What of it?

Phil: It follows that warmth can’t exist outside the mind in any unperceiving substance, or body.

Hyl: So it seems.

Phil: So we have reached the position that degrees of heat that aren’t painful and also ones that are can exist only in a thinking substance! Can’t we conclude from this that external bodies are absolutely incapable of any degree of heat whatsoever?

Hyl: On second thoughts, I am less sure that warmth is a pleasure than I am that intense heat is a pain.

Phil: I don’t claim that warmth is as great a pleasure as heat is a pain. But if you admit it to be even a small pleasure, that is enough to yield my conclusion.

Hyl: I could rather call it ‘absence of pain’. It seems to be merely the lack of pain and of pleasure. I hope you won’t deny that this quality or state is one that an unthinking substance can have!

Phil: If you are determined to maintain that warmth is not a pleasure, I don’t know how to convince you otherwise except by appealing to your own experience. But what do you think about cold?

Hyl: The same as I do about heat. An intense degree of cold is a pain; for to feel a very great cold is to experience a great discomfort, so it can’t exist outside the mind. But a lesser degree of cold can exist outside the mind, as well as a lesser degree of heat.

Phil: So when we feel a moderate degree of heat (or cold) from a body that is applied to our skin, we must conclude that that body has a moderate degree of heat (or cold) in it?

Hyl: We must.

Phil: Can any doctrine be true if it necessarily leads to absurdity?

Hyl: Certainly not.

Phil: Isn’t it an absurdity to think that a single thing should be at the same time both cold and warm?

Hyl: It is.

Phil: Well, now, suppose that one of your hands is hot and the other cold, and that they are both at once plunged into a bowl of water that has a temperature between the two. Won’t the water seem cold to one hand and warm to the other?

Hyl: It will.

Phil: Then doesn’t it follow by your principles that the water really is both cold and warm at the same time—thus believing something that you agree to be an absurdity?

Hyl: I admit that that seems right.

Phil: So the principles themselves are false, since you have admitted that no true principle leads to an absurdity.

Hyl: But, after all, can anything be more absurd than to say that there is no heat in the fire?

Phil: To make the point still clearer, answer me this: in two cases that are exactly alike, oughtn’t we to make the same judgment?

Hyl: We ought.

Phil: When a pin pricks your finger, doesn’t it tear and divide the fibres of your flesh?

Hyl: It does.

Phil: And when hot coal burns your finger, does it do any more?

Hyl: It does not.

Phil: You hold that the pin itself doesn’t contain either the sensation that it causes, or anything like it. So, given what you have just agreed to—namely that like cases should be judged alike—you ought to hold that the fire doesn’t contain either the sensation that it causes or anything like it.

Hyl: Well, since it must be so, I am content to give up this point, and admit that heat and cold are only sensations existing in our minds. Still, there are plenty of other qualities through which to secure the reality of external things.

Phil: But what will you say, Hylas, if it turns out that the same argument applies with regard to all other sensible qualities, and that none of them can be supposed to exist outside the mind, any more than heat and cold can?

Hyl: Proving that would be quite a feat, but I see no chance of your doing so.

Phil: Let us examine the other sensible qualities in order. What about tastes? Do you think they exist outside the mind, or not?

Hyl: Can anyone in his right mind doubt that sugar is sweet, or that wormwood is bitter?

Phil: Tell me, Hylas: is a sweet taste a particular kind of pleasure or pleasant sensation, or is it not?

Hyl: It is.

Phil: And isn’t bitterness some kind of discomfort or pain?

Hyl: I grant that.

Phil: If therefore sugar and wormwood are unthinking corporeal substances existing outside the mind, how can sweetness and bitterness—that is, pleasure and pain—be in them?

Hyl: Hold on, Philonous! Now I see what has deluded me all this time. You asked whether heat and cold, sweetness and bitterness, are particular sorts of pleasure and pain; to which I answered simply that they are. I should have answered by making a distinction: those qualities as perceived by us are pleasures or pains, but as existing in the external objects they are not. So we cannot conclude without qualification that there is no heat in the fire or sweetness in the sugar, but only that heat or sweetness as perceived by us are not in the fire or the sugar. What do you say to this?

Phil: I say it is irrelevant. We were talking only about ‘sensible things’, which you defined as things we immediately perceive by our senses. Whatever other qualities you are talking about have no place in our conversation, and I don’t know anything about them. You may indeed claim to have discovered certain qualities that you don’t perceive, and assert that they exist in fire and sugar; but I can’t for the life of me see how that serves your side in the argument we were having. Tell me then once more, do you agree that heat and cold, sweetness and bitterness (meaning the qualities that are perceived by the senses), don’t exist outside the mind?

Hyl: I see it is no use holding out, so I give up the cause with respect to those four qualities. Though I must say it sounds odd to say that sugar isn’t sweet.

Phil: It might sound better to you if you bear this in mind: someone whose palate is diseased may experience as bitter stuff that at other times seems sweet to him. And it’s perfectly obvious that different people perceive different tastes in the same food, since what one man delights in another loathes. How could this be, if the taste were really inherent in the food?

Hyl: I admit that I don’t know how.

Phil: Now think about odours. Don’t they exactly fit what I have just been saying about tastes? Aren’t they just so many pleasing or displeasing sensations?

Hyl: They are.

Phil: Then can you conceive it to be possible that they should exist in an unperceiving thing?

Hyl: I cannot.

Phil: Or can you imagine that filth and excrement affect animals that choose to feed on them with the same smells that we perceive in them?

Hyl: By no means.

Phil: Then can’t we conclude that smells, like the other qualities we have been discussing, cannot exist anywhere but in a perceiving substance or mind?

Hyl: I think so.

Phil: What about sounds? Are they qualities really inherent in external bodies, or not?

Hyl: They don’t inhere in the sounding bodies. We know this, because when a bell is struck in a vacuum, it sends out no sound. So the subject of sound must be the air.

Phil: Explain that, Hylas.

Hyl: When the air is set into motion, we perceive a louder or softer sound in proportion to the air’s motion; but when the air is still, we hear no sound at all.

Phil: Granting that we never hear a sound except when some motion is produced in the air, I still don’t see how you can infer from this that the sound itself is in the air.

Hyl: This motion in the external air is what produces in the mind the sensation of sound. By striking on the ear-drum it causes a vibration which is passed along the auditory nerves to the brain, whereon the mind experiences the sensation called sound.

Phil: What! is sound a sensation?

Hyl: As I said: as perceived by us it is a particular sensation in the mind.

Phil: And can any sensation exist outside the mind?

Hyl: No, certainly.

Phil: But if sound is a sensation, how can it exist in the air, if by ‘the air’ you mean a senseless substance existing outside the mind?

Hyl: Philonous, you must distinguish sound as it is perceived by us from sound as it is in itself; or—in other words—distinguish the sound we immediately perceive from the sound that exists outside us. The former is indeed a particular kind of sensation, but the latter is merely a vibration in the air.

Phil: I thought I had already flattened that distinction by the answer I gave when you were applying it in a similar case before. But I’ll let that pass. Are you sure, then, that sound is really nothing but motion?

Hyl: I am.

Phil: Whatever is true of real sound, therefore, can truthfully be said of motion.

Hyl: It may.

Phil: So it makes sense to speak of motion as something that is loud, sweet, piercing, or low-pitched!

Hyl: I see you are determined not to understand me. Isn’t it obvious that those qualities belong only to sensible sound, or ‘sound’ in the ordinary everyday meaning of the word, but not to ‘sound’ in the real and scientific sense, which (as I have just explained) is nothing but a certain motion of the air?

Phil: It seems, then, there are two sorts of sound—the common everyday sort that we hear, and the scientific and real sort that we don’t hear.

Hyl: Just so.

Phil: And the latter kind of sound consists in motion.

Hyl: As I told you.

Phil: Tell me, Hylas, which of the senses do you think the idea of motion belongs to? The sense of hearing?

Hyl: Certainly not. To the senses of sight and touch.

Phil: It should follow then, according to you, that real sounds may possibly be seen or felt, but can never be heard.

Hyl: Look, Philonous, make fun of my views if you want to, but that won’t alter the truth of things. I admit that the inferences you draw from them sound a little odd; but ordinary language is formed by ordinary people for their own use, so it’s not surprising if statements that express exact scientific notions seem clumsy and strange.

Phil: Is it come to that? I assure you, I think I have scored a pretty big win when you so casually depart from ordinary phrases and opinions; because what we were mainly arguing about was whose notions are furthest from the common road and most in conflict with what people in general think. Your claim that real sounds are never heard, and that we get our idea of sound through some other sense—can you think that this is merely an odd-sounding scientific truth? Isn’t something in it contrary to nature and the truth of things?

Hyl: Frankly, I don’t like it either. Given the concessions I have already made, I had better admit that sounds also have no real existence outside the mind.

Phil: And I hope you won’t stick at admitting the same of colours.

Hyl: Pardon me; the case of colours is very different. Can anything be more obvious than the fact that we see colours on the objects?

Phil: The objects you speak of are, I suppose, corporeal substances existing outside the mind.

Hyl: They are.

Phil: And they have true and real colours inhering in them?

Hyl: Each visible object has the colour that we see in it.

Phil: Hah! is there anything visible other than what we perceive by sight?

Hyl: There is not.

Phil: And do we perceive anything by our senses that we don’t perceive immediately?

Hyl: How often do I have to say it? I tell you, we do not.

Phil: Bear with me, Hylas, and tell me yet again whether anything is immediately perceived by the senses other than sensible qualities. I know you asserted that nothing is; but I want to know now whether you still think so.

Hyl: I do.

Phil: Now, is your corporeal substance either a sensible quality or made up of sensible qualities?

Hyl: What a question to ask! Who ever thought it was?

Phil: Here is why I ask. When you say that each visible object has the colour that we see in it, you imply that either (1) visible objects are sensible qualities, or else (2) something other than sensible qualities can be perceived by sight. But we earlier agreed that (2) is false, and you still think it is; so we are left with the thesis (1) that visible objects are sensible qualities. Now, in this conversation you have been taking it that visible objects are corporeal substances; and so we reach the conclusion that your corporeal substances are nothing but sensible qualities.

Hyl: You may draw as many absurd consequences as you please, and try to entangle the plainest things; but you will never persuade me out of my senses. I clearly understand my own meaning.

Phil: I wish you would make me understand it too! But since you don’t want me to look into your notion of corporeal substance, I shall drop that point. But please tell me whether the colours that we see are the very ones that exist in external bodies or some other colours.

Hyl: They are the very same ones.

Phil: Oh! Then are the beautiful red and purple that we see on those clouds over there really in them? Or do you rather think that the clouds in themselves are nothing but a dark mist or vapour?

Hyl: I must admit, Philonous, that those colours aren’t really in the clouds as they seem to be at this distance. They are only apparent colours.

Phil: Apparent call you them? How are we to distinguish these apparent colours from real ones?

Hyl: Very easily. When a colour appears only at a distance, and vanishes when one comes closer, it is merely apparent.

Phil: And I suppose that real colours are ones that are revealed by looking carefully from close up?

Hyl: Right.

Phil: Does the closest and most careful way of looking use a microscope, or only the naked eye?

Hyl: A microscope, of course.

Phil: But a microscope often reveals colours in an object different from those perceived by unassisted sight. And if we had microscopes that could magnify to as much as we liked, it is certain that no object whatsoever when seen through them would appear with the same colour that it presents to the naked eye.

Hyl: Well, what do you conclude from that? You can’t argue that there are really and naturally no colours on objects, just because we can contrive artificial ways to alter them or make them vanish.

Phil: It can obviously be inferred from your own concessions, I think, that all the colours we see with our naked eyes are only apparent—like those on the clouds—since they vanish when one looks more closely and accurately, as one can with a microscope. And to anticipate your next objection I ask you whether the real and natural state of an object is revealed better by a very sharp and piercing sight, or by one that is less sharp.

Hyl: By the former, without doubt.

Phil: Isn’t it plain from the science of optics that microscopes make the sight more penetrating, and represent objects as they would appear to the eye if it were naturally endowed with extreme sharpness?

Hyl: It is.

Phil: So the microscopic representation of a thing should be regarded as the one that best displays the thing’s real nature, or what the thing is in itself. so the colours perceived through a microscope are more genuine and real than those perceived in any other way.

 Hyl: I admit that there’s something in what you say.

Phil: Besides, it’s not only possible but clearly true that there actually are animals whose eyes are naturally formed to perceive things that are too small for us to see. What do you think about those inconceivably small animals that we perceive through microscopes? Must we suppose they are all totally blind? If they can see, don’t we have to suppose that their sight has the same use in preserving their bodies from injuries as eyesight does in all other animals? If it does have that use, isn’t it obvious that they must see particles that are smaller than their own bodies, which will present them with a vastly different view of each object from the view that strikes our senses? Even our own eyes don’t always represent objects to us in the same way. Everyone knows that to someone suffering from jaundice all things seem yellow. So isn’t it highly probable that animals whose eyes we see to be differently structured from ours, and whose bodily fluids are unlike ours, don’t see the same colours as we do in every object From all of this, shouldn’t it seem to follow that all colours are equally apparent, and that none of the ones that we see are really in any outer object?

Hyl: It should.

Phil: To put it past all doubt, consider the following. If colours were real properties or qualities inhering in external bodies, they couldn’t be altered except by some alteration in the very bodies themselves: but isn’t it evident that the colours of an object can be changed or made to disappear entirely through the use of a microscope, or some change in the fluids in the eye, or a change in the viewing distance, without any sort of real alteration in the thing itself? Indeed, even when all the other factors remain unaltered some objects present different colours to the eye depending on the angle from which they are looked at. The same thing happens when we view an object in different brightnesses of light. And everyone knows that the same bodies appear differently coloured by candle-light from what they do in daylight. Add to these facts our experience of a prism, which separates the different rays of light and thereby alters the colour of an object, causing the whitest object to appear deep blue or red to the naked eye. Now tell me whether you still think that each body has its true, real colour inhering in it. If you think it has, I want to know what particular distance and orientation of the object, what special condition of the eye, what intensity or kind of light is needed for discovering that true colour and distinguishing it from the apparent ones.

Hyl: I admit to being quite convinced that they are all equally apparent, that no such thing as colour really inheres in external bodies, and that colour is wholly in the light. What confirms me in this opinion is the fact that colours are more or less vivid depending on the brightness of the light, and that when there is no light no colours are seen. Furthermore, if there were colours in external objects, how could we possibly perceive them? No external body affects the mind unless it acts first on our sense-organs; and the only action of bodies is motion, and this can’t be communicated except in collisions. So a distant object can’t act on the eye, and so can’t enable itself or its properties to be perceived by the mind. From this it plainly follows that what immediately causes the perception of colours is some substance that is in contact with the eye—such as light.

Phil: What? Is light a substance?

Hyl: I tell you, Philonous, external light is simply a thin fluid substance whose tiny particles, when agitated with a brisk motion and in various ways reflected to the eyes from the different surfaces of outer objects, cause different motions in the optic nerves; these motions are passed along to the brain, where they cause various states and events; and these are accompanied by the sensations of red, blue, yellow, etc.

Phil: It seems, then, that all the light does is to shake the optic nerves.

Hyl: That is all.

Phil: And as a result of each particular motion of the nerves the mind is affected with a sensation, which is some particular colour.

Hyl: Right.

Phil: And these sensations have no existence outside the mind.

Hyl: They have not.

Phil: Then how can you say that colours are in the light, since you take light to be a corporeal substance external to the mind?

Hyl: Light and colours as immediately perceived by us cannot exist outside the mind. I admit that. But in themselves they are only the motions and arrangements of certain insensible particles of matter.

Phil: Colours then, in the ordinary sense—that is, understood to be the immediate objects of sight—cannot be had by any substance that doesn’t perceive.

Hyl: That is what I say.

Phil: Well, then, you give up your position as regards those sensible qualities which are what all mankind takes to be colours. Think what you like about the scientists’ invisible colours; it is not my business to argue about them. But I suggest that you consider whether it is wise for you, in a discussion like this one, to affirm that the red and blue we see are not real colours, and that certain unknown motions and shapes which no man ever did or could see are real colours. Aren’t these shocking notions, and aren’t they open to as many ridiculous inferences as those you had to give up in the case of sounds?

Hyl: I have to admit, Philonous, that I can’t keep this up any longer. Colours, sounds, tastes—in a word, all that are termed ‘secondary qualities’—have no existence outside the mind. But in granting this I don’t take anything away from the reality of matter or external objects, because various philosophers maintain what I just did about secondary qualities and yet are the far from denying matter. [In this context, ‘philosophers’ means ‘philosophers and scientists’.] To make this clearer: philosophers divide sensible qualities into primary and secondary. Primary qualities are extendedness, shape, solidity, gravity, motion, and rest. They hold that these really exist in bodies. Secondary qualities are all the sensible qualities that aren’t primary; and the philosophers assert that these are merely sensations or ideas existing nowhere but in the mind. No doubt you are already aware of all this. For my part, I have long known that such an opinion was current among philosophers, but I was never thoroughly convinced of its truth till now.

Phil: So you still believe that extension and shapes are inherent in external unthinking substances? [Here ‘extension’ could mean ‘extendedness’ or it could mean ‘size’.]

Hyl: I do.

Phil: But what if the arguments that are brought against secondary qualities hold against these also?

Hyl: Why, then I shall have to think that shape and extension also exist only in the mind.

Phil: Is it your opinion that the very shape and extension that you perceive by sense exist in the outer object or material substance?

Hyl: It is.

Phil: Have all other animals as good reason as you do to think that the shape and extension that they see and feel is in the outer object?

Hyl: Surely they do, if they can think at all.

Phil: Tell me, Hylas, do you think that the senses were given to all animals for their preservation and well-being in life? or were they given only to men for that end?

Hyl: I don’t doubt that they have the same use in all other animals.

Phil: If so, mustn’t their senses enable them to perceive their own limbs, and to perceive bodies that are capable of harming them?

Hyl: Certainly.

Phil: A tiny insect, therefore, must be supposed to see its own foot, and other things of that size or even smaller, seeing them all as bodies of considerable size, even though you can see them—if at all—only as so many visible points.

Hyl: I can’t deny that.

Phil: And to creatures even smaller than that insect they will seem even bigger.

Hyl: They will.

Phil: So that something you can hardly pick out because it is so small will appear like a huge mountain to an extremely tiny animal.

Hyl: I agree about all this.

Phil: Can a single thing have different sizes at the same time?

Hyl: It would be absurd to think so.

Phil: But from what you have said it follows that the true size of the insect’s foot is the size you see it having and the size the insect sees it as having, and all the sizes it is seen as having by animals that are even smaller. That is to say, your own principles have led you into an absurdity.

Hyl: I seem to be in some difficulty about this.

Phil: Another point: didn’t you agree that no real inherent property of any object can be changed unless the thing itself alters?

Hyl: I did.

Phil: But as we move towards or away from an object, its visible size varies, being at one distance ten or a hundred times greater than at another. Doesn’t it follow from this too that size isn’t really inherent in the object?

Hyl: I admit that I don’t know what to think.

Phil: You will soon be able to make up your mind, if you will venture to think as freely about this quality as you have about the others. Didn’t you admit that it was legitimate to infer that neither heat nor cold was in the water from the premise that the water seemed warm to one hand and cold to the other?

Hyl: I did.

Phil: Isn’t it the very same reasoning to infer that there is no size or shape in an object from the premise that to one eye it seems little, smooth, and round, while to the other eye it appears big, uneven, and angular?

Hyl: The very same. But does the latter ever happen?

Phil: You can at any time find out that it does, by looking with one eye bare and with the other through a microscope.

Hyl: I don’t know how to maintain it, yet I am reluctant to give up extension [= ‘size’], because I see so many odd consequences following from the concession that extension isn’t in the outer object.

Phil: Odd, you say? After the things you have already agreed to, I hope you won’t be put off from anything just because it is odd! But in any case wouldn’t it seem very odd if the general reasoning that covers all the other sensible qualities didn’t apply also to extension? If you agree that no idea or anything like an idea can exist in an unperceiving substance, then surely it follows that no shape or mode of extension [= ‘or specific way of being extended’] that we can have any idea of—in perceiving or imagining—can be really inherent in matter. Whether the sensible quality is shape or sound or colour or what you will, it seems impossible that any of these should subsist in something that doesn’t perceive it. (Not to mention the peculiar difficulty there must be in conceiving a material substance, prior to and distinct from extension, to be the substratum of extension. I’ll say more about that shortly.)

Hyl: I give up on this point, for just now. But I reserve the right to retract my opinion if I later discover that I was led to it by a false step.

Phil: That is a right you can’t be denied. Shapes and extendedness being disposed of, we proceed next to motion. Can a real motion in any external body be at the same time both very swift and very slow?

Hyl: It cannot.

Phil: Isn’t the speed at which a body moves inversely proportional to the time it takes to go any given distance? Thus a body that travels a mile in an hour moves three times as fast as it would if it travelled only a mile in three hours.

Hyl: I agree with you.

Phil: And isn’t time measured by the succession of ideas in our minds?

Hyl: It is.

Phil: And isn’t it possible that ideas should succeed one another twice as fast in your mind as they do in mine, or in the mind of some kind of non-human spirit?

Hyl: I agree about that.

Phil: Consequently the same body may seem to another spirit to make its journey in half the time that it seems to you to take. (Half is just an example; any other fraction would make the point just as well.) That is to say, according to your view that both of the perceived motions are in the object, a single body can really move both very swiftly and very slowly at the same time. How is this consistent either with common sense or with what you recently agreed to?

Hyl: I have nothing to say to it.

Phil: Now for solidity: If you don’t use ‘solidity’ to name any sensible quality, then it is irrelevant to our enquiry. If you do use it to name a sensible quality, the quality must be either hardness or resistance. But each of these is plainly relative to our senses: it is obvious that what seems hard to one animal may appear soft to another that has greater force and firmness of limbs; and it is equally obvious that the resistance I feel when I press against a body is not in the body.

Hyl: I agree that the sensation of resistance, which is all you immediately perceive, is not in the body; but the cause of that sensation is.

Phil: But the causes of our sensations aren’t immediately perceived, and therefore aren’t sensible. I thought we had settled this point.

Hyl: I admit that we did. Excuse me if I seem a little embarrassed; I am having trouble quitting my earlier views.

Phil: It may be a help for you to consider this point: once extendedness is admitted to have no existence outside the mind, the same must be granted for motion, solidity, and gravity, since obviously they all presuppose extendedness. So it is superfluous to enquire into each of them separately; in denying extendedness, you have denied them all to have any real existence.

Hyl: If this is right, Philonous, I wonder why the philosophers who deny the secondary qualities any real existence should yet attribute it to the primary qualities. If there’s no difference between them, how can this be accounted for?

Phil: It isn’t my business to account for every opinion of the philosophers! But there are many possible explanations, one of them being that those philosophers were influenced by the fact that pleasure and pain are associated with the secondary qualities rather than with the primary ones. Heat and cold, tastes and smells, have something more vividly pleasing or disagreeable than what we get from the ideas of extendedness, shape, and motion. And since it is too visibly absurd to hold that pain or pleasure can be in an unperceiving substance, men have more easily been weaned from believing in the external existence of the secondary qualities than of the primary ones. You will see that there is something in this if you recall the distinction you made between moderate heat and intense heat, allowing one a real existence outside the mind while denying it to the other. But after all, there is no rational basis for that distinction; for surely a sensation that is neither pleasing nor painful is just as much a sensation as one that is pleasing or painful; so neither kind should be supposed to exist in an unthinking subject.

Hyl: It has just come into my head, Philonous, that I have somewhere heard of a distinction between absolute and sensible extendedness. Granted that large and small consist merely in the relation other extended things have to the parts of our own bodies, and so aren’t really in the substances themselves; still, we don’t have to say the same about absolute extendedness, which is something abstracted from large and small, from this or that particular size and shape. Similarly with motion: fast and slow are altogether relative to the succession of ideas in our own minds. But just because those special cases of motion do not exist outside the mind, it doesn’t follow that the same is true of the absolute motion that is abstracted from them.

Phil: What distinguishes one instance of motion, or of extendedness, from another? Isn’t it something sensible—for instance some speed, or some size and shape?

Hyl: I think so.

Phil: So these qualities—namely, absolute motion and absolute extendedness—which are stripped of all sensible properties, have no features making them more specific in any way.

Hyl: That is right.

Phil: That is to say, they are extendedness in general, and motion in general.

Hyl: If you say so.

Phil: But everyone accepts the maxim that every thing that exists is particular. How then can motion in general, or extendedness in general, exist in any corporeal substance?

Hyl: I will need time to think about that.

Phil: I think the point can be speedily decided. Without doubt you can tell whether you are able to form this or that idea in your mind. Now I’m willing to let our present dispute be settled in the following way. If you can form in your thoughts a distinct abstract idea of motion or extendedness, having none of those sensible qualities—swift and slow, large and small, round and square, and the like—which we agree exist only in the mind, then I’ll capitulate. But if you can’t, it will be unreasonable for you to insist any longer on something of which you have no notion.

Hyl: To be frank, I cannot.

Phil: Can you even separate the ideas of extendedness and motion from the ideas of all the so-called secondary qualities?

Hyl: What! isn’t it easy to consider extendedness and motion by themselves, abstracted from all other sensible qualities? Isn’t that how the mathematicians handle them?

Phil: I acknowledge, Hylas, that it is not difficult to form general propositions and reasonings about extendedness and motion, without mentioning any other qualities, and in that sense to treat them abstractedly. I can pronounce the word ‘motion’ by itself, but how does it follow from this that I can form in my mind the idea of motion without an idea of body? Theorems about extension and shapes can be proved without any mention of large or small or any other sensible quality, but how does it follow from this that the mind can form and grasp an abstract idea of extension, without any particular size or shape or other sensible quality? Mathematicians study quantity, disregarding any other sensible qualities that go with it on the grounds that they are irrelevant to the proofs. But when they lay aside the words and contemplate the bare ideas, I think you’ll find that they aren’t the pure abstracted ideas of extendedness.

Hyl: But what do you say about pure intellect? Can’t abstracted ideas be formed by that faculty?

Phil: Since I can’t form abstract ideas at all, it is clearly impossible for me to form them with help from ‘pure intellect’, whatever faculty you mean that phrase to refer to. Setting aside questions about the nature of pure intellect and its spiritual objects such as virtue, reason, God, etc., I can say this much that seems clearly true: sensible things can only be perceived by the senses or represented by the imagination; so shape and size don’t belong to pure intellect because they are initially perceived through the senses. If you want to be surer about this, try and see if you can frame the idea of any shape, abstracted from all particularities of size and from other sensible qualities.

Hyl: Let me think a little—I don’t find that I can.

Phil: Well, can you think it possible that something might really exist in nature when it implies a contradiction in its conception?

Hyl: By no means.

Phil: Therefore, since even the mind can’t possibly separate the ideas of extendedness and motion from all other sensible qualities, doesn’t it follow that where the former exist the latter must also exist?

Hyl: It would seem so.

Phil: Consequently the very same arguments that you agreed to be decisive against the secondary qualities need no extra help to count just as strongly against the primary qualities also. Besides, if you trust your senses don’t they convince you that all sensible qualities co-exist, that is, that they all appear to the senses as being in the same place? Do your senses ever represent a motion or shape as being divested of all other visible and tangible qualities?

Hyl: You needn’t say any more about this. I freely admit—unless there has been some hidden error or oversight in our discussion up to here—that all sensible qualities should alike be denied existence outside the mind. But I fear that I may have been too free in my former concessions, or overlooked some fallacy in your line of argument. In short, I didn’t take time to think.

Phil: As to that, Hylas, take all the time you want to go back over our discussion. You are at liberty to repair any slips you have made, or to support your initial opinion by presenting arguments that you have so far overlooked.

Hyl: I think it was a big oversight on my part that I failed to distinguish sufficiently the object from the sensation. The sensation cannot exist outside the mind, but it doesn’t follow that the object cannot either.

Phil: What object do you mean? The object of the senses?

Hyl: Exactly.

Phil: So it is immediately perceived?

Hyl: Right.

Phil: Explain to me the difference between what is immediately perceived and a sensation.

Hyl: I take the sensation to be an act of the perceiving mind; beside which, there is something perceived, which I call the object of the act. For example, there is red and yellow on that tulip, but the act of perceiving those colours is in me only, and not in the tulip.

Phil: What tulip are you talking about? Is it the one that you see?

Hyl: The same.

Phil: And what do you see beside colour, shape, and extendedness?

Hyl: Nothing.

Phil: So you would say that the red and yellow are co-existent with the extension, wouldn’t you?

Hyl: Yes, and I go further: I say that they have a real existence outside the mind in some unthinking substance.

Phil: That the colours are really in the tulip which I see, is obvious. Nor can it be denied that this tulip may exist independently of your mind or mine; but that any immediate object of the senses—that is, any idea or combination of ideas—should exist in an unthinking substance, or exterior to all minds, is in itself an obvious contradiction. Nor can I imagine how it follows from what you said just now, namely that the red and yellow are in the tulip you saw, since you don’t claim to see that unthinking substance.

Hyl: You are skillful at changing the subject, Philonous.

Phil: I see that you don’t want me to push on in that direction. So let’s return to your distinction between sensation and object. If I understand you correctly, you hold that in every perception there are two things of which one is an action of the mind and the other is not.

Hyl: True.

Phil: And this action can’t exist in or belong to any unthinking thing; but whatever else is involved in a perception may do so.

Hyl: That is my position.

Phil: So that if there were a perception without any act of the mind, that perception could exist in an unthinking substance.

Hyl: I grant that. But it is impossible that there should be such a perception.

Phil: When is the mind said to be active?

Hyl: When it produces, puts an end to, or changes anything.

Phil: Can the mind produce, discontinue, or change anything in any way except by an act of the will?

Hyl: It cannot.

Phil: So the mind is to count as being active in its perceptions to the extent that volition is included in them.

Hyl: It is.

Phil: When I pluck this flower I am active, because I do it by a hand-movement which arose from my volition; so likewise in holding it up to my nose. But is either of these smelling?

Hyl: No.

Phil: I also act when I draw air through my nose, because my breathing in that manner rather than otherwise is an effect of my volition. But this isn’t smelling either; for if it were, I would smell every time I breathed in that manner.

Hyl: True.

Phil: Smelling, then, is a result of all this plucking, holding up, and breathing in.

Hyl: It is.

Phil: But I don’t find that my will is involved any further—that is, in anything other than the plucking, holding up, and breathing in. Whatever else happens—including my perceiving a smell—is independent of my will, and I am wholly passive with respect to it. Is it different in your case, Hylas?

Hyl: No, it’s just the same.

Phil: Now consider seeing: isn’t it in your power to open your eyes or keep them shut, to turn them this way or that?

Hyl: Without doubt.

Phil: But does it similarly depend on your will that when you look at this flower you perceive white rather than some other colour? When you direct your open eyes towards that part of the sky, can you avoid seeing the sun? Or is light or darkness the effect of your volition?

Hyl: No, certainly.

Phil: In these respects, then, you are altogether passive.

Hyl: I am.

Phil: Tell me now, does seeing consist in perceiving light and colours or rather in opening and turning the eyes?

Hyl: The former, certainly.

Phil: Well, then, since in the actual perception of light and colours you are altogether passive, what has become of that action that you said was an ingredient in every sensation? And doesn’t it follow from your own concessions that the perception of light and colours—which doesn’t involve any action—can exist in an unperceiving substance? And isn’t this a plain contradiction?

Hyl: I don’t know what to think.

Phil: Furthermore, since you distinguish active and passive elements in every perception, you must do it in the perception of pain. But how could pain—however inactive it is—possibly exist in an unperceiving substance? Think about it, and then tell me frankly: aren’t light and colours, tastes, sounds, etc. all equally passions or sensations in the mind? You may call them ‘external objects’, and give them in words whatever kind of existence you like; but examine your own thoughts and then tell me whether I am not right?

Hyl: I admit, Philonous, that when I look carefully at what goes on in my mind, all I can find is that I am a thinking being that has a variety of sensations; and I can’t conceive how a sensation could exist in an unperceiving substance. But when on the other hand I look in a different way at sensible things, considering them as so many properties and qualities, I find that I have to suppose a material substratum, without which they can’t be conceived to exist.

Phil: Material substratum you call it? Tell me, please, which of your senses acquainted you with it?

Hyl: It is not itself sensible; only its properties and qualities are perceived by the senses.

Phil: I presume, then, that you obtained the idea of it through reflection and reason.

Hyl: I don’t claim to have any proper positive idea of it. [Here ‘positive’ means ‘non-relational’: Hylas means that he doesn’t have an idea that represents what material substance is like in itself.] But I conclude that it exists, because qualities can’t be conceived to exist without a support.

Phil: So it seems that you have only a relative notion of material substance: you conceive it only by conceiving how it relates to sensible qualities.

Hyl: Right.

Phil: Tell me, please, what that relation is.

Hyl: Isn’t it sufficiently expressed in the term ‘substratum’ or ‘substance’? [One is Latin, and means ‘underneath layer’; the other comes from Latin meaning ‘standing under’.]

Phil: If so, the word ‘substratum’ should mean that it is spread under the sensible qualities.

Hyl: True.

Phil: And consequently spread under extendedness.

Hyl: I agree.

Phil: So in its own nature it is entirely distinct from extendedness.

Hyl: I tell you, extendedness is only a quality, and matter is something that supports qualities. And isn’t it obvious that the supported thing is different from the supporting one?

Phil: So something distinct from extendedness, and not including it, is supposed to be the substratum of extendedness.

Hyl: Just so.

Phil: Tell me, Hylas, can a thing be spread without being extended? Isn’t the idea of extendedness necessarily included in that of spreading?

Hyl: It is.

Phil: So anything that you suppose to be spread under something else must have in itself an extendedness distinct from the extendedness of the thing under which it is spread.

Hyl: It must.

Phil: Consequently every bodily substance, being the substratum of extendedness, must have in itself another extendedness which qualifies it to be a substratum, and that extendedness must also have something spread under it, a sub-substratum, so to speak, and so on to infinity. Isn’t this absurd in itself, as well as conflicting with what you have just said, namely that the substratum was something distinct from extendedness and not including it?

Hyl: Yes, but Philonous you misunderstand me. I don’t mean that matter is ‘spread’ in a crude literal sense under extension. The word ‘substratum’ is used only to express in general the same thing as ‘substance’.

Phil: Well, then, let us examine the relation implied in the term ‘substance’. Is it not the relation of standing under qualities?

Hyl: The very same.

Phil: But doesn’t a thing have to be extended if it is to stand under or support another?

Hyl: Yes.

Phil: So isn’t this supposition infected with the same absurdity as the previous one?

Hyl: You still take things in a strict literal sense; that isn’t fair, Philonous.

Phil: I don’t want to force any meaning onto your words; you are free to explain them as you please. But please make me understand something by them! You tell me that matter supports or stands under accidents. How? As your legs support your body?

Hyl: No; that is the literal sense.

Phil: Please let me know any sense, literal or not literal, that you understand it in.—How long must I wait for an answer, Hylas?

Hyl: I don’t know what to say. I once thought I understood well enough what was meant by matter’s ‘supporting’ qualities. But now the more I think about it the less I understand it. In short, I find that I don’t know anything about it.

Phil: So it seems that you have no idea at all, either positive or relative, of matter. You don’t know what it is in itself, or what relation it has to qualities.

Hyl: I admit it.

Phil: And yet you said that you couldn’t conceive the real existence of qualities without conceiving at the same time a material support for them.

Hyl: I did.

Phil: That amounted to saying that when you conceive the real existence of qualities you also conceive something that you can’t conceive!

Hyl: It was wrong, I admit. But still I fear there is some fallacy or other. Let me try this: It has just occurred to me that we were both led into error by your treating each quality by itself. I grant that no quality can exist on its own outside the mind; colour can’t exist without extension, nor can shape exist without some other sensible quality. But as a number of qualities united or blended together constitute an entire sensible thing, there is no obstacle to supposing that such things—that is, such collections of qualities—can exist outside the mind.

Phil: Are you joking, Hylas, or do you have a very bad memory? We did indeed go through all the qualities by name, one after another; but my arguments—or rather your concessions—nowhere tended to prove that the

secondary qualities don’t exist outside the mind in isolation;

the point was rather that

secondary qualities don’t exist outside the mind at all.

It’s true that existing-in-isolation did come up in our discussion: in discussing shape and motion, we concluded they couldn’t exist outside the mind because it was impossible even in thought to separate them from all secondary qualities, so as to conceive them existing by themselves. But this wasn’t the only argument I used on that occasion. However, if you like we can set aside our whole conversation up to here, counting it as nothing. I am willing to let our whole debate be settled as follows: If you can conceive it to be possible for any mixture or combination of qualities, or any sensible object whatever, to exist outside the mind, then I will grant it actually to be so.

Hyl: By that test, the point will soon be decided. What is easier than to conceive a tree or house existing by itself, independently of and unperceived by any mind whatsoever? I conceive them existing in that way right now.

Phil: Tell me, Hylas, can you see a thing which is at the same time unseen?

Hyl: No, that would be a contradiction.

Phil: Is it not as great a contradiction to talk of conceiving a thing which is unconceived?

Hyl: It is.

Phil: The tree or house therefore which you think of is conceived by you.

Hyl: How could it be otherwise?

Phil: And what is conceived is surely in the mind.

Hyl: Without question, what is conceived is in the mind.

Phil: Then what led you to say that you conceived a house or tree existing independently and out of all minds whatsoever?

Hyl: That was an oversight, I admit; but give me a moment to think about what led me into it. It was—I now realize, after reflection—an amusing mistake. As I was thinking of a tree in a solitary place with nobody there to see it, I thought that was conceiving a tree as existing unperceived or unthought of, overlooking the fact I myself conceived it all the while. But now I plainly see that all I can do is to form ideas in my own mind. I can conceive in my own thoughts the idea of a tree, or a house, or a mountain, but that is all. And this is far from proving that I can conceive them existing out of the minds of all spirits.

Phil: You agree, then, that you can’t conceive how any corporeal sensible thing should exist otherwise than in a mind.

Hyl: I do.

Phil: And yet you will earnestly contend for the truth of something that you can’t even conceive.

Hyl: I admit that I don’t know what to think, but I still have doubts. Isn’t it certain that I see things at a distance? Don’t we perceive the stars and moon, for example, to be a long way away? Isn’t this, I say, obvious to the senses?

Phil: Don’t you in dreams also perceive objects like those?

Hyl: I do.

Phil: And don’t they then appear in the same way to be distant?

Hyl: They do.

Phil: But do you conclude that the apparitions in a dream are outside the mind?

Hyl: By no means.

Phil: Then you ought not to conclude that sensible objects seen when you are awake are outside the mind, from their appearance or the manner in which you perceive them.

Hyl: I admit that. But doesn’t my visual sense deceive me in those cases, by telling me that sensible objects are at a distance when really they are not?

Phil: By no means. Neither eyesight nor reason inform you that the idea or thing that you immediately perceive actually exists outside the mind. By eyesight you know only that you are affected with certain sensations of light and colours, etc. And you won’t say that these are outside the mind.

Hyl: True; but all the same, don’t you think that eyesight makes some suggestion of outerness or distance?

Phil: When you approach a distant object, do the visible size and shape keep changing, or do they appear the same at all distances?

Hyl: They are in a continual change.

Phil: So sight doesn’t ‘suggest’ or in any way inform you that the visible object you immediately perceive exists at a distance, or that it will be perceived when you move further forward; because there is a continued series of visible objects succeeding each other during the whole time of your approach.

Hyl: I agree about that: but still I know, on seeing an object, what object I shall see after I have gone a certain distance—never mind whether it is exactly the same object or not. So something about distance is still being suggested.

Phil: My dear Hylas, just think about that a little, and then tell me whether there is anything more to it that this: From the ideas that you actually perceive by sight you have by experience learned to infer (in accordance with the general rules of nature) what other ideas you will experience after such and such a succession of time and motion.

Hyl: Upon the whole, I think that’s what it comes down to.

Phil: Isn’t it obvious that if a man born blind were suddenly enabled to see, he would start with no experience of what may be suggested by sight?

Hyl: It is.

Phil: So he would not, according to you, have any notion of distance linked to the things he saw. He would take the latter to be a new set of sensations existing only in his mind.

Hyl: That is undeniable.

Phil: But to make it still more plain: isn’t distance a line running out from the eye?

Hyl: It is.

Phil: Can a line so situated be perceived by sight?

Hyl: It cannot.

Phil: So doesn’t it follow that distance isn’t strictly and immediately perceived by sight?

Hyl: It seems so.

Phil: Again, do you think that colours are at a distance?

Hyl: I have to acknowledge that they are only in the mind.

Phil: But don’t colours appear to the eye as coexisting at the same place as extension and shape

Hyl: They do.

Phil: Then how can you conclude from the deliverances of sight that shapes do exist outside the mind, when you agree that colours don’t? The sensible appearances of both are the very same.

Hyl: I don’t know what to answer.

Phil: Even if distance were truly and immediately perceived by the mind, it still wouldn’t follow that it existed out of the mind. For whatever is immediately perceived is an idea; and can any idea exist out of the mind?

Hyl: It would be absurd to suppose so. But tell me, Philonous, can we perceive or know nothing except our ideas?

Phil: Set aside what we may know through the rational deducing of causes from effects; that is irrelevant to our enquiry. As for the senses: you are the best judge of whether you perceive anything that you don’t immediately perceive. And I ask you, are the things you immediately perceive anything but your own sensations or ideas? In the course of this conversation you have more than once declared yourself on those two points; this latest question of yours seems to indicate that you have changed your mind.

Hyl: To tell you the truth, Philonous, I think there are two kinds of objects: one kind perceived immediately, and called ‘ideas’; the other kind are real things or external objects perceived by the mediation of ideas, which resemble and represent them. Now I grant that ideas don’t exist outside the mind; but the second sort of objects do. I am sorry I didn’t think of this distinction sooner; it would probably have cut short your discourse.

Phil: Are those external objects perceived by sense, or by some other faculty?

Hyl: They are perceived by sense.

Phil: What? Is there anything perceived by sense that isn’t immediately perceived?

Hyl: Yes, Philonous, there is—in a way. For example, when I look at a picture or statue of Julius Caesar, I may be said to perceive him in a fashion (though not immediately) by my senses.

Phil: You seem to hold, then, that our ideas, which are all that we immediately perceive, are pictures of external things; and that the latter are also perceived by sense because they have a conformity or resemblance to our ideas.

Hyl: That is my meaning.

Phil: And in the same way that Julius Caesar, in himself invisible, is nevertheless perceived by sight, so also real things, in themselves imperceptible, are perceived by sense.

Hyl: In the very same way.

Phil: Tell me, Hylas, when you look at the picture of Julius Caesar, do you see with your eyes anything more than some colours and shapes, with a certain symmetry and composition of the whole?

Hyl: Nothing else.

Phil: And wouldn’t a man who had never known anything about Julius Caesar see as much?

Hyl: He would.

Phil: So he has his sight, and the use of it, as perfectly as you have yours.

Hyl: I agree with you.

Phil: Then why are your thoughts directed to the Roman emperor while his are not? This can’t come from the sensations or ideas of sense that you perceive at that moment, for you have agreed that you have in that respect no advantage over the man who has never heard of Julius Caesar. So it seems that the direction of your thoughts comes from reason and memory—doesn’t it?

Hyl: It does.

Phil: So that example of yours doesn’t show that anything is perceived by sense that isn’t immediately perceived. I don’t deny that we can be said in a certain sense to perceive sensible things mediately by sense: that is when the immediate perception of ideas by one sense suggests to the mind others, perhaps belonging to another sense, of a kind that have often been perceived to go with ideas of the former kind. For instance, when I hear a coach drive along the streets, all that I immediately perceive is the sound; but from my past experience that such a sound is connected with a coach, I am said to ‘hear the coach’. Still, it is obvious that in truth and strictness nothing can be heard but sound; and the coach in that example is not strictly perceived by sense but only suggested from experience. Similarly, when we are said to see a red-hot bar of iron; the solidity and heat of the iron are not the objects of sight, but are suggested to the imagination by the colour and shape that are strictly perceived by that sense. In short,

the only things that are actually and strictly perceived by any sense are the ones that would have been perceived even if we had only just acquired that sense and were using it for the first time.

As for other things, clearly they are only suggested to the mind by past experience. But to return to your comparison of imperceptible ‘real things’ with Caesar’s picture: obviously, if you keep to this you’ll have to hold that the real things that our ideas copy are perceived not by sense but by some internal faculty of the soul such as reason or memory. I would be interested to know what arguments reason gives you for the existence of your ‘real things’ or material objects; or whether you remember seeing them formerly not as copied by your ideas but as they are in themselves; or if you have heard or read of anyone else who did!

Hyl: I can see that you want to make fun of me, Philonous; but that will never convince me.

Phil: All I want is to learn from you how to come by knowledge of material things. Whatever we perceive is perceived either immediately by sense, or mediately by reason and reflection. But you have excluded sense; so please show me what reason you have to believe in their existence, or what means you can possibly adopt to prove, to my understanding or your own, that they exist.

Hyl: To be perfectly frank, Philonous, now that I think about it I can’t find any good reason for my position. But it seems pretty clear that it’s at least possible that such things really exist; and as long as there is no absurdity in supposing them, I shall continue in my belief until you bring good reasons to the contrary.

Phil: What? Has it come to this, that you believe in the existence of material objects, and that this belief is based on the mere possibility of its being true? Then you challenge me to bring reasons against it; though some people would think that the burden of proof lies with him who holds the affirmative position. Anyway, this very thesis that you are now determined to maintain without any reason is in effect one that you have—more than once during this conversation—seen good reason to give up. But let us set all that aside. If I understand you rightly, you say our ideas don’t exist outside the mind, but that they are copies, likenesses, or representations of certain originals that do.

Hyl: You have me right.

Phil: Our ideas, then, are like external things.

Hyl: They are.

Phil: Do those external things have a stable and permanent nature independently of our senses; or do they keep changing as we move our bodies and do things with our faculties or organs of sense?

Hyl: Real things, obviously, have a fixed and real nature which remains the same through any changes in our senses or in how our bodies are placed or how they move. Such changes may indeed affect the ideas in our minds, but it would be absurd to think they had the same effect on things existing outside the mind.

Phil: How, then, can things that are perpetually fleeting and variable as our ideas are be copies or likenesses of any thing that is fixed and constant? Since all sensible qualities—size, shape, colour, etc.—that is, our ideas, are continually changing with every alteration in the distance, medium, or instruments of sensation, how can any fixed material object be properly represented or depicted by several distinct things or ideas, each of which is so unlike the others? Or if you say that the object resembles just one of our ideas, how can we distinguish that true copy from all the false ones?

Hyl: I have to admit, Philonous, that I am at a loss. I don’t know what to say to this.

Phil: There is more. Are material objects in themselves perceptible or imperceptible?

Hyl: Properly and immediately nothing can be perceived but ideas. All material things, therefore, are in themselves insensible, and can be perceived only through ideas of them.

Phil: Ideas are sensible, then, and their originals—the things they are copies of—are insensible?

Hyl: Right.

Phil: But how can something that is sensible be like something that is insensible? Can a real thing, in itself invisible, be like a colour? Can a real thing that isn’t audible be like a sound? In a word, can anything be like a sensation or idea but another sensation or idea?

Hyl: I must admit that I think not.

Phil: Can there possibly be any doubt about this? Don’t you perfectly know your own ideas?

Hyl: Yes, I know them perfectly; for something that I don’t perceive or know can’t be any part of my idea.

Phil: Well, then, examine your ideas, and then tell me if there’s anything in them that could exist outside the mind, or if you can conceive anything like them existing outside the mind.

Hyl: Upon looking into it I find that I can’t conceive or understand how anything but an idea can be like an idea. And it is most evident that no idea can exist outside the mind.

Phil: So you’re forced by your own principles to deny the reality of sensible things, because you made it consist in an absolute existence outside the mind. That is to say, you are a downright sceptic. So I have met my target, which was to show that your principles lead to scepticism.

Hyl: For the present I am, if not entirely convinced, at least silenced.

Phil: I wonder what more you would require in order to be perfectly convinced. Haven’t you been free to explain yourself in any way you liked? Were any little conversational slips held against you? Weren’t you allowed to retract or reinforce anything you had previously said, as best served your purpose? Hasn’t everything you could say been heard and examined with all the fairness imaginable? In a word, haven’t you on every point been convinced out of your own mouth? And if you can now discover any flaw in any of your former concessions, or think of any remaining tactic, any new distinction, shading, or comment whatsoever, why don’t you produce it?

Hyl: A little patience, Philonous. I am at present so bewildered to see myself entangled, and as it were imprisoned in the labyrinths you have led me into, that I can’t be expected to find my way out on the spur of the moment. You must give me time to look around me, and recollect myself.

Phil: Listen—isn’t that the college-bell? Let us go in, and meet here again tomorrow morning. In the mean time you can think about this morning’s conversation, and see if you can find any fallacy in it, or invent any new means to extricate yourself.

Hyl: Agreed.

The Second Dialogue

Hylas: I beg your pardon, Philonous, for not meeting you sooner. All this morning my head was so filled with our recent conversation that I didn’t notice the time of the day, or indeed anything else!

Philonous: I am glad you were so focussed on it. I hope that if there were any mistakes in your concessions, or fallacies in my reasonings from them, you will now show them to me.

Hyl: I assure you, ever since I saw you I have done nothing but search for mistakes and fallacies, and with that in mind I have examined in detail the whole course of yesterday’s conversation. But it has all been useless; for the views I was led into in the conversation seemed even clearer and more obvious when I reviewed them today; and the more I think about them the more irresistibly they force my assent to them.

Phil: Don’t you think that this is a sign that they are genuine, and that they proceed from nature and are in accordance with right reason? Truth and beauty have this in common: they both show to advantage when looked at closely and carefully. The false glitter of error and heavy make-up can’t endure being looked at for too long or from too close up!

Hyl: I admit there is a great deal in what you say. And I am as convinced as anyone could be of the truth of those strange consequences that you argued for yesterday, so long as I keep in mind the reasonings that lead to them. But when those arguments are out of my thoughts, my mind goes the other way; there seems to be something so satisfactory, natural and intelligible in the modern way of explaining things that I confess that I don’t know how to reject it.

Phil: I don’t know what way you mean.

Hyl: I mean the modern way of accounting for our sensations or ideas.

Phil: How does it do that?

Hyl: It is supposed that the mind resides in some part of the brain, from which the nerves originate, spreading out from there to all parts of the body; that outer objects act in different ways on the sense-organs, starting up certain vibrations in the nerves; that the nerves pass these vibrations along to the brain (where the mind is located); and that the mind is variously affected with ideas according to the various impressions or traces the vibrations make in the brain.

Phil: And call you this an explanation of how we are affected with ideas?

Hyl: Why not, Philonous? Have you any objection to it?

Phil: I need to know first whether I have rightly understood your ‘modern’ hypothesis. According to it, certain traces in the brain are the causes or occasions of our ideas. [The special meaning of ‘occasion’ that is at work here will be explained on page 46; it doesn’t matter in the mean time.] Tell me, please, do you mean by ‘the brain’ a sensible thing?

Hyl: What else do you think I could possibly mean?

Phil: Sensible things are all immediately perceivable; and things that are immediately perceivable are ideas; and these exist only in the mind. This much, if I am not mistaken, you have long since agreed to.

Hyl: I don’t deny it.

Phil: So the brain that you speak of, being a sensible thing, exists only in the mind! I would like to know whether you think it reasonable to suppose that one idea or thing existing in the mind occasions all the other ideas. And if you do think this, how do you account for the origin of that primary idea or ‘brain’ itself?

Hyl: I don’t explain the origin of our ideas by the brain which is perceivable to sense, because it is as you say only a combination of sensible ideas. I am talking about another brain, which I imagine.

Phil: But aren’t imagined things just as much in the mind as perceived things are?

Hyl: I must admit that they are.

Phil: So the difference between perceiving and imagining isn’t important. You have been accounting for ideas by certain motions or impressions in the brain, that is, by some alterations in an idea—and it doesn’t matter whether it is sensible or imaginable.

Hyl: I begin to suspect my hypothesis.

Phil: Apart from spirits, our own ideas are the only things we know or conceive. So when you say that all ideas are occasioned by impressions in the brain, do you conceive this brain or not? If you do, then you talk of ideas imprinted on an idea, causing that same idea, which is absurd. If you don’t conceive it, you talk unintelligibly instead of forming a reasonable hypothesis.

Hyl: I can now see clearly that it was a mere dream. There is nothing in it.

Phil: It’s no great loss; for, after all, this way of ‘explaining’ things (as you called it) could never have satisfied any reasonable man. What connection is there between a vibration in the nerves and sensations of sound or colour in the mind? How could one possibly cause the other?

Hyl: But I could never have seen it as being so empty as it now seems to be!

Phil: Well, then, are you finally satisfied that no sensible things have a real existence, and that you are in truth a complete sceptic?

Hyl: It is too plain to be denied.

Phil: Look! aren’t the fields covered with a delightful green? Isn’t there something in the woods and groves, in the rivers and clear springs, that soothes, delights, transports the soul? At the view of the wide and deep ocean, or some huge mountain whose top is lost in the clouds, or of an old gloomy forest, aren’t our minds filled with a pleasing horror? Even in rocks and deserts, isn’t there an agreeable wildness? It is such a sincere pleasure to see earth’s natural beauties! Doesn’t she preserve and renew our enjoyment of them by intermittently drawing the veil of over her face, and doesn’t she change her dress with the seasons? How aptly the elements are disposed! What variety and usefulness even in the lowest things that nature produces! What delicacy, what beauty, what complexity of organization in the bodies of animals and plants! How finely all things are suited to their particular ends and also to their roles as appropriate parts of the whole! And while they mutually aid and support, don’t they also display each other in a better light? Raise now your thoughts from this globe of earth to all those glorious glittering objects that adorn the high arch of heaven. The motion and situation of the planets—aren’t they admirably orderly? Have those globes ever been known to stray in their repeated journeys through pathless space? Doesn’t each of them sweep out the same area between itself and the sun in any two equal periods of time? So fixed and unchanging are the laws by which the unseen Author of nature runs the universe. How vivid and radiant is the shine of the fixed stars! How magnificent and rich the careless profusion with which they seem to be scattered throughout the whole vault of the sky! Yet the telescope brings into view a new host of stars that escape the naked eye. Here they seem to be nearby and small, but a closer view through a telescope shows them to be immense orbs of light at various distances, sunk deep in the abyss of space. Now you must call imagination to your aid so as to get some imaginative picture of things you can’t actually see. Our feeble limited senses can’t pick out innumerable worlds (planets) revolving round the central fires (suns), in each of which the energy of an all-perfect mind is displayed in endless forms; so those are things you must simply imagine. But neither sense nor imagination is big enough to take in the boundless extent of the universe with all its glittering furniture. With all the hard work that we give to those two faculties, exerting and straining each of them to its utmost reach, there’s always a vast surplus left ungrasped. Yet all the vast bodies that make up this mighty universe, however distant they may be, are by some secret mechanism—some divine power and artifice—linked in a mutual dependence and interconnection with each other, and with this earth (which almost slipped out of my thoughts, getting lost in the crowd of worlds!). Isn’t the whole system immense, beautiful, more glorious than we can say or think? Then how should we treat those philosophers who want to deprive these noble and delightful scenes of all reality? How should we think of principles implying that all the visible beauty of the creation is a false imaginary glare? To put it bluntly, can you expect this scepticism of yours not to be thought extravagantly absurd by all reasonable people?

Hyl: Other men may think as they please, but you have nothing to reproach me with. My comfort is that you are as much a sceptic as I am.

Phil: There, Hylas, I beg leave to differ from you.

Hyl: What? Having along agreed to the premises, are you now denying the conclusion and leaving me to maintain by myself these paradoxes that you led me into? This surely isn’t fair.

Phil: I deny that I agreed with you in those views that led to scepticism. You indeed said that the reality of sensible things consisted in an absolute existence out of the minds of spirits, or distinct from their being perceived. And under the guidance of this notion of reality you are obliged to deny that sensible things have any real existence; that is, according to your own definition [on page 4] you declare yourself to be a sceptic. But I didn’t say and didn’t think that the reality of sensible things should be defined in that manner. To me it is evident, for the reasons you agree to, that sensible things can’t exist except in a mind or spirit. From this I conclude not that they have no real existence but that—seeing they don’t depend on my thought, and have an existence distinct from being perceived by me—there must be some other mind in which they exist. As sure as the sensible world really exists, therefore, so sure is there an infinite, omnipresent Spirit who contains and supports it.

Hyl: What? This is no more than I and all Christians hold—and indeed all non-Christians who believe there is a God and that he knows and understands everything.

Phil: Yes, but here’s the difference. Men commonly believe that all things are known or perceived by God because they believe in the existence of a God, whereas for me the order of reasons is reversed; I immediately and necessarily conclude the existence of a God because all sensible things must be perceived by him.

Hyl: As long as we all believe the same thing, what does it matter how we come by that belief?

Phil: But we don’t believe the same thing. Philosophers hold that God perceives all corporeal things, but they attribute to such things an absolute existence independently of their being perceived by any mind whatever; and I don’t. Besides, isn’t there a difference between saying

There is a God, therefore he perceives all things

and saying

Sensible things do really exist; if they really exist they must be perceived by an infinite mind; therefore there is an infinite mind, or God?

This provides you with a direct and immediate proof, from a most evident premise, of the existence of a God. Theologians and philosophers had proved beyond all controversy, from the beauty and usefulness of the various parts of the creation, that it was the workmanship of God. But some of us have the advantage that we can prove the existence of an infinite mind from the bare existence of the sensible world, without getting help from astronomy and natural philosophy and without bringing in facts about how wonderfully the parts of the world relate to one another. What gives us this advantage is just the simple thought that the sensible world is what we perceive by our various senses, that nothing is perceived by the senses except ideas, and that no idea and no thing of which an idea is a copy can exist otherwise than in a mind. With that at your disposal you can now oppose and baffle the most strenuous advocate for atheism, without any laborious search into the sciences, without any sophisticated reasoning, and without tediously long arguments. This single reflection on impossibility that the visible world or any part of it—even the most low-grade and shapeless part of it—should exist outside a mind is enough to overthrow the whole system of atheism. It destroys those miserable refuges of the atheist, the eternal succession of unthinking causes and effects, or the chance coming together of atoms—those wild fantasies of Vanini, Hobbes, and Spinoza. Let any one of those supporters of impiety look into his own thoughts, and see if he can conceive how so much as a rock, a desert, a chaos, or a confused jumble of atoms—how anything at all, either sensible or imaginable—can exist independently of a mind; and he need go no further to be convinced of his folly. Can anything be fairer than to let the disagreement be settled by the outcome of such a test, leaving it to the atheist himself to see if he can conceive, even in thought, the state of affairs that he holds to be true in fact?

Hyl: It is undeniable that there is something highly serviceable to religion in the position you are taking. But don’t you think it looks very like the view of some eminent recent philosophers—notably Malebranche—that we ‘see all things in God’?

Phil: I would gladly know about that; please explain it to me.

Hyl: They think that because the soul (or mind) is immaterial, it can’t be united with material things so as to perceive them in themselves, but that it perceives them through its union with the substance of God. Because that is a spiritual substance, it is purely intelligible, that is, capable of being the immediate object of a human mind’s thought. Furthermore, God’s essence contains perfections corresponding to each created thing, and this correspondence enables those perfections to represent created things to the human mind.

Phil: I don’t understand how our ideas, which are entirely passive and inert, can be (or be like) any part of the essence of God, who is indivisible, never passive, always active. This hypothesis is open to many other obvious objections, but I shall only add that in making a created world exist otherwise than in the mind of a spirit, the hypothesis of Malebranche is liable to all the absurdities of the more usual views. Added to which it has a special absurdity all its own, namely that it makes the material world serve no purpose. If it is valid to argue against other hypotheses in the sciences that they suppose nature or the Divine Wisdom to make something for no purpose, or to employ tedious round-about methods to get a result which could have been achieved much more easily and swiftly, what are we to think of this hypothesis which supposes that the whole world was made for no purpose?

Hyl: But don’t you also hold that we see all things in God? If I’m not mistaken, your thesis comes near to that.

Phil: Few men think, but all insist on having opinions, which is why men’s opinions are superficial and confused. It isn’t surprising that doctrines which in themselves are ever so different should nevertheless be confused with one another by people who don’t think hard about them. So I shan’t be surprised if some men imagine that I run into the wild fantasies of Malebranche, though in truth I am very remote from them. He builds on the most abstract general ideas, which I entirely disclaim. He asserts an absolute external world, which I deny. He maintains that we are deceived by our senses, and don’t know the real natures or the true forms and shapes of extended things; of all which I hold the direct contrary! So that over-all there are no principles more fundamentally opposite than his and mine. I have to say that I entirely agree with what the Holy Scripture says, that ‘in God we live and move and have our being’. But I am far from believing that we ‘see things in his essence’ in the manner you have presented. Here is my view, in a nutshell:

It is evident that the things I perceive are my own ideas, and that no idea can exist except in a mind. It is equally obvious that these ideas, or things perceived by me—or things of which they are copies—exist independently of my mind, because I know that I am not their author, it being out of my power to choose what particular ideas I shall experience when I open my eyes or ears. So they must exist in some other mind, who wills that they be exhibited to me.

The things I immediately perceive, I repeat, are ideas or sensations, call them what you will. But how can any idea or sensation exist in or be produced by anything other than a mind or spirit? That really is inconceivable; and to assert something that is inconceivable is to talk nonsense, isn’t it?

Hyl: Without doubt.

Phil: On the other side, it is very conceivable that ideas or sensations should exist in, and be produced by, a spirit; because this is just what I experience daily in myself, when I perceive countless ideas, and by an act of my will can form a great variety of them, raising them up in my imagination. (Though I have to say that these creatures of my imagination are not as distinct, strong, vivid, and permanent as are the ones I perceive through my senses, which latter are called ‘real things’.) From all this I conclude that there is a mind that affects me every moment with all the sensible impressions I perceive. And from the variety, order, and manner of these impressions I conclude that the author of them is wise, powerful, and good, beyond anything I can comprehend. Please get this straight: I do not say—as Malebranche does—that I see things by perceiving something that represents them in the intelligible essence of God. I don’t even understand that. What I say is this: the things I perceive are known by the understanding, and produced by the will, of an infinite Spirit. Isn’t all this very plain and evident? Is there anything more in it than what a little observation of our own minds and what happens in them not only enables us to conceive but also obliges us to assent to?

Hyl: I think I understand you very clearly; and I admit that the proof you give of a Deity is as convincing as it is surprising. But granting that God is the supreme and universal cause of all things, mightn’t there be a third kind of thing besides spirits and ideas? May we not admit a subordinate and limited cause of our ideas? In a word, may there not for all that be matter?

Phil: How often must I teach you the same thing? You agree that the things immediately perceived by sense exist nowhere outside the mind; but everything that is perceived by sense is perceived immediately; therefore there is nothing sensible or perceivable that exists outside the mind. So the matter that you still insist on is presumably meant to be something intelligible—something that can be discovered by reason and not by the senses.

Hyl: You are in the right.

Phil: Pray let me know what reasoning your belief in matter is based on; and what this ‘matter’ is, in your present sense of the word.

Hyl: I find myself affected with various ideas which I know I haven’t caused. And they couldn’t cause themselves or cause one another, nor could they exist on their own, because they are wholly inactive, transient, dependent beings. So they have some cause other than me and other than themselves; all I claim to know about this is that it is the cause of my ideas. And this thing, whatever it is, I call ‘matter’.

Phil: Tell me, Hylas, is everyone free to change the current proper meaning of a common word in any language? For example, suppose a traveller told you that in a certain country men can ‘pass unhurt through the fire’; and when he explained himself you found that he meant by ‘fire’ what others call ‘water’; or suppose he said that there are trees that walk on two legs, meaning men by the term ‘trees’. Would you think this reasonable?

Hyl: No; I should think it very absurd. Common custom is the standard of correctness in language. And deliberately to speak improperly is to pervert the use of speech, and can’t achieve anything except to prolong and multiply disputes when there is no real difference of opinion.

Phil: And doesn’t ‘matter’, in the common current meaning of the word, signify an extended, solid, movable, unthinking, inactive substance?

Hyl: It does.

Phil: And hasn’t it been made evident that no such substance can possibly exist? And even if it did exist, how can something inactive be a cause? and how can something unthinking be a cause of thought? You are free to give the word ‘matter’ a meaning that is contrary to its ordinary one, and to tell me that you understand by ‘matter’ an unextended, thinking, active being, which is the cause of our ideas. But this is just playing with words, committing the very fault that you have just now rightly condemned. I don’t find fault with your reasoning, in that you infer a cause from the phenomena; but I deny that the cause that reason allows you to infer can properly be called ‘matter’.

Hyl: There is indeed something in what you say. But I am afraid you don’t properly grasp what I mean. I wouldn’t want you to take me to be denying that God, or an infinite spirit, is the supreme cause of all things. All I am arguing is that subordinate to the supreme agent or cause there is a cause of a limited and lower kind, which concurs in [= ‘goes along with’] the production of our ideas, not by the action proper to spirits (namely acts of will) but by the action proper to matter (namely motion).

Phil: You keep relapsing into your old exploded notion of a movable (and consequently extended) substance existing outside the mind. What! have you already forgotten what you were convinced of? Do you want me to repeat everything I have said about this? Really, this isn’t arguing fairly, still to assume the existence of something that you have so often admitted not to exist. But letting that go, I ask Aren’t all your ideas perfectly passive and inert, including no kind of action in them?

Hyl: They are.

Phil: And are sensible qualities anything else but ideas?

Hyl: How often have I agreed that they are not?

Phil: But isn’t motion a sensible quality?

Hyl: It is.

Phil: Consequently it is no action.

Hyl: I agree with you. And indeed it is obvious that when I move my finger it remains passive; but my will that produced the motion is active.

Phil: Now I want to know in the first place whether, given that motion is not action, you can conceive any action other than volition; in the second place whether to say something and conceive nothing is not to talk nonsense; and lastly, whether having considered the premises, you don’t see that it is highly absurd and unreasonable to suppose that our ideas have any efficient or active cause other than spirit.

Hyl: I give up the point entirely. But although matter may not be a cause, what blocks it from being an instrument subservient to the supreme agent in the production of our ideas?

Phil: An instrument, you say. Please tell me about the shape, springs, wheels, and motions of that instrument?

Hyl: I don’t claim to be able to do that, because both this substance and its qualities are entirely unknown to me.

Phil: What? So you think it is made up of unknown parts, and has unknown motions and an unknown shape.

Hyl: I don’t think it has any shape or motion at all, because you have convinced me that no sensible qualities can exist in an unperceiving substance.

Phil: But what notion can we possibly have of an instrument that has no sensible qualities, not even extension?

Hyl: I don’t claim to have any notion of it.

Phil: And what reason do you have to think that this unknown and inconceivable something does exist? Is it that you think God cannot act as well without it, or that you find by experience that some such thing is at work when you form ideas in your own mind?

Hyl: You are always nagging me for reasons for what I believe. What reasons do you have for not believing it?

Phil: For me, seeing no reason for believing something is a sufficient reason for not believing it. But, setting aside reasons for believing, you will not so much as let me know what it is you want me to believe, since you say you have no sort of notion of it. I beg you to consider whether it is like a philosopher, or even like a man of common sense, to claim to believe you know not what and you know not why.

Hyl: Hold on, Philonous! When I tell you that matter is an ‘instrument’, I don’t mean absolutely nothing. Admittedly I don’t know what the particular kind of instrument it is; but still I have some notion of instrument in general, which I apply to it.

Phil: But what if it should turn out that even the most general notion of instrument, understood as meaning something distinct from cause, contains something that makes the use of an instrument inconsistent with the divine attributes?

Hyl: Show me that and I shall give up the point.

Phil: I shall now do so. What do you mean by the general nature or notion of instrument?

Hyl: The general notion is made up of what is common to all particular instruments.

Phil: Don’t all instruments have this in common: they are used only in doing things that can’t be performed by the mere act of our wills? Thus, for instance, I never use an instrument to move my finger, because it is done by a volition. But I would use an instrument if I wanted to remove part of a rock or tear up a tree by the roots. Do you agree with this? Or can you show any example where an instrument is used in producing an effect which immediately depends on the will of the agent?

Hyl: I admit that I can’t.

Phil: Well, then, how can you suppose that an all-perfect Spirit, on whose will all things absolutely and immediately depend, would need an instrument in his operations, or that he would use one if he didn’t need it? Thus, it seems to me, you have to admit that it would be incompatible with the infinite perfection of God for him to use a lifeless inactive instrument such as matter is supposed to be. That is, your own statements oblige you to give up the point.

Hyl: No answer to that comes readily to mind.

Phil: There is an answer that should come to your mind. You should be ready to admit to the truth when it has been fairly proved to you. I shall state the proof again. We beings whose powers are finite are forced to make use of instruments. And the use of an instrument shows that the agent is limited by rules that were prescribed by someone else and not by him, and that he cannot get what he wants except in such-and-such a way and in such-and-such conditions. This seems clearly to imply that the supreme unlimited agent uses no tool or instrument at all. An omnipotent Spirit has only to will that something happen and it happens, straight off, without the use of any means. When means are employed by inferior agents like you and me, it isn’t because of any real causal power that is in them, any necessary fitness to produce the desired effect. Rather, it is to comply with the laws of nature, or those conditions prescribed to us by God, the first cause, who is himself above all limitation or prescription whatsoever.

Hyl: I will no longer maintain that matter is an instrument. But don’t take me to be giving up on its existence, because, despite everything you have said, it may still be an occasion.

Phil: How many shapes is your matter to take? How often must it be proved not to exist before you are content to let it go? By all the laws of debate I am entitled to blame you for so frequently changing the meaning of the principal term (‘matter’), but I shan’t press that point. Instead, I ask you this: having already denied matter to be a cause, what do you mean when you affirm that it is an occasion? And when you have shown what you mean by ‘occasion’, then please show me what reason leads you to believe there is such an occasion of our ideas.

Hyl: As to the first point: by ‘occasion’ I mean an inactive, unthinking being, at the presence of which God causes ideas in our minds.

Phil: And what may be the nature of that inactive, unthinking being?

Hyl: I know nothing of its nature.

Phil: Proceed then to the second point, and give me some reason why we should believe in the existence of this inactive, unthinking, unknown thing.

Hyl: When we see ideas produced in our minds in an orderly and constant manner, it is natural to think they have some fixed and regular occasions at the presence of which they are excited.

Phil: You acknowledge then that God alone is the cause of our ideas, and that he causes them in the presence of those occasions.

Hyl: That is what I think.

Phil: No doubt God perceives the things that you say are present to him.

Hyl: Certainly; otherwise they couldn’t provide him with occasions of acting.

Phil: Without insisting now on your making sense of this hypothesis, or on your answering all the puzzling questions and difficulties that beset it, I merely ask:

Isn’t the order and regularity found in the series of our ideas—that is, the course of nature—sufficiently explained by the wisdom and power of God?

Doesn’t it take away from God’s wisdom and power to suppose that any unthinking substance influences or directs him concerning what to do and when to do it?

Even if I granted you all that you contend for regarding matter as God’s occasion for acting, would you get the result you want?

The point of the last question is that it’s hard to see how the external or absolute existence of an unthinking substance, distinct from its being perceived, can be inferred from there being certain things perceived by the mind of God which are to him the occasion of producing ideas in us.

Hyl: I am utterly at a loss about what to think. This notion of occasion now seems to be just as groundless as the rest.

Phil: Don’t you at last see that in all these different senses of ‘matter’ you have only been supposing you know not what, for no reason, and to no purpose?

Hyl: I freely admit to having become less fond of my notions, since you have examined them in such precise detail. But still, I think I have some confused perception that there is such a thing as matter.

Phil: Either you perceive the existence of matter immediately, or you perceive it mediately. If immediately, please tell me by which of the senses you perceive it. If mediately, let me know what reasoning you employ to infer it from things that you do perceive immediately. So much for the perception. Then for the matter itself: I ask whether it is object, substratum, cause, instrument, or occasion? You have already argued for each of these, shifting your notions and making matter appear first in one guise and then in another. And each thing you have offered has been disapproved and rejected by yourself. If you have anything new to advance, I would gladly hear it.

Hyl: I think I have already offered all I had to say on those topics. I am at a loss what more to urge.

Phil: And yet you’re reluctant to part with your old prejudice. But to make it easier for you to drop it, I ask you to consider—as well as all my other points—the question of how you could possibly be affected by matter if it did exist. And the question of whether it would make any difference to the ideas you experience—and thus make any difference to your reasons to believe in its existence—if matter didn’t exist?

Hyl: I agree that it is possible we might perceive all things just as we do now without there being any matter in the world; and in answer to your first question, I can’t conceive how matter—if there is such a thing—could produce any idea in our minds. And I also admit that you have entirely satisfied me that it is impossible for there to be such a thing as matter in any of the previous senses of the term. But still I can’t help supposing that there is matter in some sense or other. I don’t claim to settle what sense that is.

Phil: I don’t demand that you define exactly the nature of that unknown being. Just tell me whether it is a substance; and if it is, whether you can suppose a substance without qualities; and if on the other hand you suppose it to have qualities, please tell me what those qualities are, or at least what it means to say that matter ‘supports’ them.

Hyl: We have already argued on those points. I have no more to say about them. But to head off any further questions, let me tell you that I now understand by ‘matter’ neither substance nor accident, thinking nor extended being, neither cause, instrument, nor occasion, but something entirely unknown, different from all those.

Phil: It seems then that you include in your present notion of matter nothing but the general abstract of idea of entity or thing.

Hyl: Nothing else, except that I add to this general idea of thing the negation of all those particular things, qualities, or ideas that I perceive, imagine, or in any way apprehend.

Phil: Where, please, do you suppose that this unknown matter exists?

Hyl: Oh Philonous! now you think you have entangled me; for if I say it exists in some place, you will infer that it exists in the mind, since we agree that place or extension exists only in the mind; but I am not ashamed to admit my ignorance. I don’t know where it exists; but I am sure it doesn’t exist in a place. There is a negative answer for you; and such answers are all you can expect to get for all your remaining questions about matter.

Phil: Since you won’t tell me where it exists, please inform me about how you suppose it to exist, or what you mean by saying that it ‘exists’.

Hyl: It neither thinks nor acts, neither perceives nor is perceived.

Phil: But what positive content is there in your abstracted notion of its existence?

Hyl: When I look into it carefully I don’t find that I have any positive notion or meaning at all. I tell you again: I am not ashamed to admit my ignorance. I don’t know what is meant by its ‘existence’, or how it exists.

Phil: Keep up this frankness, good Hylas, and tell me sincerely whether you can form a distinct idea of entity in general, abstracting from and excluding all thinking and corporeal beings, all particular things whatsoever.

Hyl: Hold on, let me think a little—I confess, Philonous, I don’t find that I can. At first glance I thought I had some dilute and airy notion of pure entity in abstract; but when I focussed on it, it vanished. The more I think about it, the more am I confirmed in my wise decision to give only negative answers to your questions and not to claim the slightest positive knowledge or conception of matter, its where, its how, its entity, or anything about it.

Phil: So when you speak of the ‘existence of matter’, you have no notion in your mind.

Hyl: None at all.

Phil: Here is where I think we have got to; please tell me if I am wrong. You attributed existence outside the mind first to

the immediate objects of our perceptions (this came from your belief in material substance); then to

their archetypes—the things of which they are copies; then to

their causes; then to

instruments; then to

occasions; and lastly to

something in general, which on examination turns out to be nothing.

So matter comes to nothing. What do you think, Hylas? Isn’t this a fair summary of your whole proceeding?

Hyl: Be that as it may, yet I still insist that our not being able to conceive a thing is no argument against its existence.

Phil: I freely grant that the existence of a thing that is not immediately perceived may reasonably be inferred from a cause, effect, operation, sign, or other circumstance; and that it would be absurd for any man to argue against the existence of that thing, from his having no direct and positive notion of it. But where there is nothing of all this; where

neither reason nor revelation induces us to believe in the existence of a thing,

we don’t have even a relative notion of it,

what is offered is so abstract that it rises above the distinction between perceiving and being perceived (between spirit and idea), and lastly

not even the most inadequate or faint idea of it is claimed to exist—

where all this is the case, I shan’t indeed draw any conclusion against the reality of any notion or against the existence of anything; but I shall infer that you mean nothing at all, that you are using words to no purpose, without any design or meaning whatsoever. And I leave it to you to consider how such mere jargon should be treated.

Hyl: To be frank, Philonous, your arguments seem in themselves unanswerable, but their effect on me has not been enough to produce that total conviction, that whole-hearted agreement, that comes with demonstration [= ‘rigorous knock-down proof’]. I find myself still relapsing into an obscure surmise of something-or-other that I call ‘matter’.

 Phil: But don’t you realize, Hylas, that two things must co-operate to take away all doubts and produce a complete mental assent? However clear the light is in which a visible object is set, it won’t be distinctly seen if there is any imperfection in the vision or if the eye is not directed towards it. And however solid and clearly presented a demonstration is, yet if there is also prejudice or wrong bias in the understanding, can it be expected all at once to see the truth clearly and adhere to it firmly? No! For that to happen, time and effort are needed; the attention must be awakened and held by frequent repetition of the same thing—often in the same light, often in different lights. I have said it already, and find I must still repeat it to get you to accept it: when you claim to accept you don’t know what, for you don’t know what reason, and for you don’t know what purpose, you are taking extraordinary liberties. Can this be parallelled in any art or science, any sect or profession of men? Or is there anything so shamelessly groundless and unreasonable to be met with even in the lowest of common conversation? But you persist in saying ‘Matter may exist’, without knowing what you mean by ‘matter’ or what you mean by saying that it ‘exists’. What makes this especially surprising is the fact that it’s something you have just decided to say; you aren’t led to it by any reasons at all; for I challenge you to show me something in nature that needs matter to explain or account for it.

Hyl: The reality of things can’t be maintained without supposing the existence of matter. Don’t you think this is a good reason why I should be earnest in its defence?

Phil: The reality of things! What things, sensible or intelligible?

Hyl: Sensible things.

Phil: My glove, for example?

Hyl: That or any other thing perceived by the senses.

Phil: Let us fix on one particular thing. Isn’t it a sufficient evidence to me of the existence of this glove that I see it and feel it and wear it? And if it isn’t, how could I be assured of the reality of this thing, which I actually see in this place, by supposing that some unknown thing which I never did or can see exists in an unknown manner, in an unknown place, or in no place at all? How can the supposed reality of something intangible be a proof that anything tangible really exists? Or of something invisible that any visible thing really exists? Put generally: how can the supposed reality of something imperceptible be a proof of the existence of a perceptible thing? Explain this and I shall think that nothing is too hard for you!

Hyl: Over-all I am content to admit that the existence of matter is highly improbable; but I don’t see that it is directly and absolutely impossible.

Phil: Even if matter is granted to be possible, that doesn’t give it a claim to existence, any more than a golden mountain or a centaur, which are also possible.

Hyl: I admit that; but still you don’t deny that it is possible; and something that is possible may, for all you know, actually exist.

Phil: I do deny it to be possible; and I think I have proved that it isn’t, from premises that you have conceded. In the ordinary sense of the word ‘matter’, is anything more implied than an extended, solid, shaped, movable substance, existing outside the mind? And haven’t you admitted over and over that you’ve seen evident reason for denying the possibility of such a substance?

Hyl: True, but that is only one sense of the term ‘matter’.

Phil: But isn’t it the only proper, genuine, commonly accepted sense? And if matter in such a sense is proved impossible, may it not be thought with good grounds to be absolutely impossible? Otherwise how could anything be proved impossible? Indeed, how could there be any proof at all, of anything, to a man who feels free to unsettle and change the common meanings of words?

Hyl: I thought philosophers might be allowed to speak more accurately than common people do, and were not always confined to the common meaning of a term.

Phil: But the meaning I have stated is the common accepted sense among philosophers. Anyway, setting that point aside, haven’t I let you take ‘matter’ in whatever sense you pleased? And haven’t you used this privilege to the utmost extent, sometimes entirely changing the meaning, at others leaving out or putting into the definition of ‘matter’ whatever at that moment best served your purposes, contrary to all the known rules of reason and logic? And hasn’t this shifting, unfair method of yours spun out our dispute to an unnecessary length, matter having been scrutinised in each particular one of those senses and, by your own admission, refuted in each of them? And can any more be required to prove the absolute impossibility of a thing than to prove it to be impossible in every particular sense that you or anyone else understands it in?

Hyl: I am not so thoroughly satisfied that you have proved the impossibility of matter in the last most obscure, abstracted and indefinite sense.

Phil: When is a thing shown to be impossible?

Hyl: When an inconsistency is demonstrated between the ideas contained in its definition.

Phil: But where there are no ideas, no contradiction between ideas can be demonstrated.

Hyl: I agree with you.

Phil: Now, consider the sense of the word ‘matter’ that you have just called obscure and indefinite: by your own admission it is obvious that this includes no idea at all, no sense—except an unknown sense, which is the same thing as none. So you can’t expect me to prove an inconsistency between ideas where there are no ideas, or to prove the impossibility of ‘matter’ taken in an unknown sense, that is, in no sense at all. I aimed only to show that you meant nothing; and I got you to admit that. So that in all your various senses you have been shown to mean nothing at all, or if something then an absurdity. If this isn’t sufficient to prove the impossibility of a thing, I wish you would tell me what is.

 Hyl: I admit that you have proved that matter is impossible; nor do I see what else can be said in defence of it. But when I give up matter I come to suspect all my other notions. For surely none could be more seemingly evident than this once was; yet it now seems as false and absurd as it previously seemed true. But I think we have discussed the point enough for the present. I would like to spend the rest of today running over in my thoughts the various parts of this morning’s conversation, and I’ll be glad to meet you again here tomorrow at about the same time.

 Phil: I’ll be here.

The Third Dialogue

Philonous: Tell me, Hylas, what has come of yesterday’s meditation? Has it confirmed you in the views you held when we parted? Or has it given you cause to change your opinion?

Hylas: Truly my opinion is that all our opinions are equally useless and uncertain. What we approve today we condemn tomorrow. We make a fuss about knowledge, and spend our lives in the pursuit of it, yet all the time, alas! we know nothing; and I don’t think we can ever know anything in this life. Our faculties are too narrow and too few. Nature certainly never intended us for speculation [= ‘for the pursuit of true theories’].

Phil: What? You say we can know nothing, Hylas?

Hyl: There isn’t one single thing in the world whose real nature we can know.

Phil: Are you going to tell me that I don’t really know what fire or water is?

Hyl: You may indeed know that fire appears hot, and water fluid; but that is merely knowing what sensations are produced in your own mind when fire or water is applied to your sense-organs. You are utterly in the dark as to their internal constitution, their true and real nature.

Phil: Don’t I know that this is a real stone that I’m standing on, and that what I see before my eyes is a real tree?

Hyl: Know? No, it is impossible that you or any man alive should know it. All you know is that you have such and such an idea or appearance in your own mind. But what does that have to do with the real tree or stone? I tell you, the colour, shape, and hardness that you perceive aren’t the real natures of those things, or in the least like them. The same may be said of all other real things or corporeal substances that make up the world. None of them has in itself anything like the sensible qualities that we perceive. So we shouldn’t claim to affirm or know anything about them as they are in their own nature.

Phil: But surely, Hylas, I can distinguish gold, for example, from iron. How could I do that if I didn’t know what either truly was?

Hyl: Believe me, Philonous, you can only distinguish between your own ideas. That yellowness, that weight, and other sensible qualities—do you think that they are really in the gold? They are only relations to the senses, and have no absolute existence in nature. And in claiming to distinguish the species of real things on the basis of the appearances in your mind, you may be acting as foolishly as someone who inferred that two men were of a different species because their clothes were of different colours.

Phil: It seems, then, that we are fobbed off with the appearances of things, and false appearances at that. The food I eat and the clothes I wear have nothing in them that is like what I see and feel.

Hyl: Just so.

Phil: But isn’t it strange that everyone should be thus deceived. and be so foolish as to believe their senses? And yet men (I don’t know how) eat and drink and sleep and get on with their lives as comfortably and conveniently as if they really knew the things they have to deal with.

Hyl: They do so; but you know ordinary practical affairs don’t require precise theoretical knowledge. So the common people can retain their mistakes and yet manage to bustle through the affairs of life. But philosophers know better things.

Phil: You mean, they know that they know nothing.

Hyl: That is the very peak and perfection of human knowledge.

Phil: But are you serious about all this, Hylas? Are you really convinced that you know nothing real in the world? If you were going to write, wouldn’t you call for pen, ink, and paper, like anyone else? And wouldn’t you know what it was you were calling for?

Hyl: How often must I tell you that I don’t know the real nature of any single thing in the universe? It is true that I sometimes use pen, ink, and paper, but I declare positively that I don’t know what any of them is in its own true nature. And the same is true with regard to every other corporeal thing. Furthermore, we are ignorant not only of the true and real nature of things but even of their existence. It can’t be denied that we perceive certain appearances or ideas; but it can’t be concluded from this that bodies really exist. Indeed, now that I think about it, my former concessions oblige me to declare that it is impossible that any real corporeal thing should exist in nature.

Phil: You amaze me! Was ever anything more wild and extravagant than the notions you now maintain? Isn’t it evident that you are led into all these extravagances by the belief in material substance? That’s what makes you dream of those unknown natures in every thing. It is what leads you to distinguish the reality of things from their sensible appearances. It is to this that you are indebted for being ignorant of what everyone else knows perfectly well. Nor is this all: you are ignorant not only of the true nature of every thing, but of whether any thing really exists, or whether there are any true natures at all; because you attribute to your ‘material beings’ an absolute or external existence and suppose that their reality consists in that. As you are eventually forced to admit that such an existence means either a direct contradiction or nothing at all, it follows that you are obliged to pull down your own hypothesis of material substance, and positively to deny the real existence of any part of the universe. And so you are plunged into the deepest and most deplorable scepticism that anyone ever suffered from. Tell me, Hylas, isn’t that what has happened?

Hyl: Yes, it is. Material substance was no more than an hypothesis, and a false and groundless one too. I will no longer waste my breath defending it. But whatever hypothesis you advance, whatever system you introduce in place of it, I am sure it will appear every bit as false, if you allow me to question you about it. Allow me to treat you as you have me, and I’ll lead you through as many perplexities and contradictions to the very same state of scepticism that I myself am in at present.

Phil: I assure you, Hylas, I don’t claim to formulate any hypothesis at all. I have the common man’s frame of mind; I am simple enough to believe my senses and to leave things as I find them. Here’s what I think, in plain words. The real things are the very things I see and feel and perceive by my senses. I know these; and because I find that they satisfy all the needs and purposes of life, I have no reason to worry about any other unknown beings. A piece of sensible [= ‘perceptible’] bread, for instance, would appease my hunger better than ten thousand times as much of that insensible, unintelligible, ‘real’ bread you speak of. It is also my opinion that colours and other sensible qualities are in the objects. I can’t for the life of me help thinking that snow is white, and fire hot. You indeed, who by ‘snow’ and ‘fire’ mean certain external, unperceived, unperceiving substances, are right to deny whiteness or heat to be qualities inherent in them. But I, who understand by ‘snow’ and ‘fire’ the things I see and feel, am obliged to think as other folk do. And as I am no sceptic about the nature of things, I am not a sceptic either about their existence. That a thing should be really perceived by my senses, and at the same time not really exist, is to me a plain contradiction; since I cannot abstract, even in thought, the existence of a sensible thing from its being perceived. Wood, stones, fire, water, flesh, iron, and other such things that I name and talk about are things that I know. And I wouldn’t have known them if I hadn’t perceived them by my senses; and

things perceived by the senses are immediately perceived; and

things that are immediately perceived are ideas; and

ideas can’t exist outside the mind.

So it follows that

the existence of things I perceive by my senses consists in being perceived.

When they are actually perceived, therefore, there can be no doubt about their existence. Away, then, with all that scepticism, all those ridiculous philosophical doubts! What a joke is it for a philosopher to question the existence of sensible things until it is proved to him from the truthfulness of God, or to claim that our knowledge about this falls short of the knowledge we have of things that are obviously self-evident or rigorously proved. I might as well doubt my own existence as the existence of the things that I actually see and feel.

Hyl: Not so fast, Philonous! You say that you can’t conceive how sensible things should exist outside the mind—don’t you?

Phil: I do.

Hyl: Supposing you were annihilated, can’t you conceive it to be possible that things perceivable by sense might still exist?

Phil: I can; but then it must be in another mind. When I say that sensible things can’t exist out of the mind, I don’t mean my mind in particular, but all minds. Now, they clearly have an existence exterior to my mind, since I find by experience that they are independent of it. There is therefore some other mind in which they exist during the intervals between the times when I perceive them; as likewise they did before my birth, and would do after my supposed annihilation. And as the same is true with regard to all other finite created minds, it necessarily follows that there is an omnipresent, eternal Mind which knows and comprehends all things, and lets us experience them in a certain manner according to rules that he himself has ordained and that we call the ‘laws of nature’. [Although ‘comprehends’ can mean ‘understands’, here it probably means ‘includes’—all things are known by, and are in, the mind of God.]

Hyl: Tell me, Philonous: are all our ideas perfectly inert beings? Or have they any agency included in them?

Phil: They are altogether passive and inert.

Hyl: And isn’t God an agent, a being purely active?

Phil: I agree.

Hyl: So an idea cannot be like God, or represent his nature.

Phil: It cannot.

Hyl: If you have no idea of the mind of God, how can you conceive it to be possible that things exist in his mind? That is, if you have no idea of his mind, how can you have any thought about his mind? On the other hand, if you can have a thought about the mind of God without having an idea of him, then why can’t I conceive the existence of matter without having an idea of it?

 Phil: I acknowledge that strictly speaking I have no idea either of God or any other spirit; for these, being active, can’t be represented by things that are perfectly inert, as our ideas are. Still, even though I have no idea of myself because I am a spirit or thinking substance, I know that I exist. I know this, indeed, as certainly as I know that my ideas exist. I also know what I mean by the terms ‘I’ and ‘myself’; and I know this immediately or intuitively, though I don’t perceive it as I perceive a triangle, a colour or a sound. The mind (spirit, soul) is the indivisible and unextended thing that thinks, acts and perceives. It is indivisible because it is unextended; and it is unextended because the only extended, shaped, movable things are ideas; and something that perceives ideas, and that thinks and wills, clearly can’t itself be an idea. Ideas are inactive things that are perceived: and spirits are things of a totally different sort. So I deny that my soul is an idea, or like an idea. However, my soul can be said to furnish me with an ‘idea’ of God in a broad sense of the word ‘idea’—that is, an image or likeness of God, though indeed an extremely inadequate one. I get my notion of God by reflecting on my own soul, heightening its powers and removing its imperfections. My basic thought of God, therefore, is the thought of ‘a thing that is like me except…’ and so on. So although I have no inert idea of God in my mind, I do have in myself a kind of active image of him because I myself am an image = likeness of him. And though I don’t perceive him by sense, still I have a notion of him, which is to say that I know him by reflection and reasoning. I immediately know my own mind and my own ideas; and these give me, in an indirect way, a grasp of the possibility that other spirits and ideas exist. Further, from the fact that I exist and the fact that I find that my ideas of sense aren’t caused by me, I reason my way to the unavoidable conclusion that a God exists and that all created things exist in his mind. So much for your first question. By this time you can probably answer your second question for yourself. I have shown that there are four different ways in which things can come before the mind, and none of them is a way in which matter could come before your mind. (i) You don’t perceive matter by mentally representing it, as you do an inactive being or idea; (ii) nor do you know it, as you know yourself, by an act of mentally attending to yourself. (iii) You don’t understand it indirectly, through a resemblance between it and either your ideas or yourself; and (iv) you don’t bring it into your mind by reasoning from what you know immediately. All of this makes the case of matter widely different from that of God, because your knowledge of him involves (iii) and (iv).

 Hyl: You say that your own soul supplies you with a kind of idea or image of God; but you admit that strictly speaking you have no idea of your soul. You even assert that spirits are utterly different in kind from ideas, which means that no idea can be like a spirit, which implies that there can be no idea of a spirit. So you have no idea of spiritual substance, yet you insist that spiritual substance exists. On the other hand, from your having no idea or notion of material substance you infer that material substance doesn’t exist. Is that fair? To be consistent you should either admit matter or reject spirit. What do you say to this?

Phil: My answer falls into three parts. (1) I don’t deny the existence of material substance merely because I have no notion of it, but because the notion of it is inconsistent—to have a notion of it would involve a self-contradiction. For all I know to the contrary, there may exist many things of which none of us has or can have any idea or notion whatsoever. But such things must be possible, i.e. nothing inconsistent must be included in their definition. (2) Although we believe in the existence of some things that we don’t perceive, we oughtn’t to believe that any particular thing exists without some reason for thinking so; but I have no reason for believing in the existence of matter. I have no immediate intuition of it; and I can’t infer it—rigorously or even by probable inference—from my sensations, ideas, notions, actions or passions. In contrast with this, I undeniably know by reflection the existence of myself, that is, my own soul, mind, or source of thought. You will forgive me if I repeat the same things in answer to the same objections. The notion or definition of material substance includes an obvious inconsistency, and that is not so for the notion of spirit. That ideas should exist in something that doesn’t perceive, or be produced by something that doesn’t act, is inconsistent. But there is no inconsistency in saying that a perceiving thing is the subject of ideas, or that an active thing causes them. I concede that the existence of other finite spirits is not immediately evident to us, nor have we any way of rigorously proving it; but that doesn’t put such spirits on a level with material substances, because there are the following three differences. It is inconsistent to suppose there is matter, but not to suppose there are finite spirits; there is no argument for matter, while there are probable reasons in favour of spirits; there are no signs or symptoms that make it reasonable to believe in matter, but we see signs and effects indicating that there are other finite agents like ourselves. (3) Although I don’t have an idea of spirit, if ‘idea’ is used strictly, I do have a notion of it. I don’t perceive it as an idea, or by means of an idea, but I know it by reflection on myself.

Hyl: Despite all that you have said, it seems to me that according to your own way of thinking, and by your own principles, you should conclude that you are only a system of floating ideas without any substance to support them. Words shouldn’t be used without a meaning; and as there is no more meaning in ‘spiritual substance’ than in ‘material substance’, the former is to be exploded as well as the latter.

Phil: How often must I repeat it? I know or am conscious of my own existence; and I know that I myself am not my ideas but something else—a thinking, active principle [here = ‘force or source of energy’] which perceives, knows, wills and operates on ideas. I know that I, one and the same self, perceive both colours and sounds; that a colour cannot perceive a sound, nor a sound a colour; and therefore that I am one individual thing, distinct from colour and sound and (for the same reason) distinct from all other sensible things and inert ideas. But I am not in the same way conscious of either the existence or the essence of matter. On the contrary, I know that nothing inconsistent can exist, and that the existence of matter implies an inconsistency. Furthermore, I know what I mean when I assert that there is a spiritual substance or support of ideas, that is, that a spirit knows and perceives ideas. But I don’t know what people mean when they say that an unperceiving substance contains and supports either ideas or items of which ideas are copies. So there is no significant likeness between spirit and matter.

Hyl: I admit to being satisfied about this. But do you seriously think that the real existence of sensible things consists in their being actually perceived? If so, how does it come about that all mankind distinguish between them? Ask the first man you meet, and he’ll tell you that to be perceived is one thing and to exist is another.

Phil: I am content, Hylas, to appeal to the common sense of the world for the truth of my view. Ask the gardener why he thinks that cherry tree over there exists in the garden, and he will tell you, because he sees and feels it—in short, because he perceives it by his senses. Ask him why he thinks there is no orange-tree there, and he will tell you, because he doesn’t perceive one. When he perceives something by sense, he terms it a real thing and says that it exists; and anything that isn’t perceivable he says doesn’t exist.

Hyl: Yes, Philonous, I agree that the existence of a sensible thing consists in being perceivable, but not in being actually perceived.

Phil: And what is perceivable but an idea? And can an idea exist without being actually perceived? These are points long since agreed between us.

Hyl: However true your view is, you must admit that it is shocking, and contrary to the common sense of men. Ask your gardener whether that tree has an existence out of his mind; what answer do you think he would give you?

Phil: The same answer that I would give, namely, that it does exist out of his mind. But then surely to a Christian it can’t be shocking to say that the real tree existing outside his mind is truly known and comprehended by (that is, exists in) the infinite mind of God. Probably the gardener won’t at first glance be aware of the direct and immediate proof there is of this—namely that the very existence of a tree or any other perceptible thing implies a mind that contains it. But the point itself is one that he can’t deny. What is at issue between the materialists and me is not whether things have a real existence outside the mind of this or that person, but whether they exist outside all minds, having an existence that doesn’t involve being perceived by God. Some heathens and philosophers have indeed affirmed this, but anyone whose notions of God are appropriate to the holy scriptures will think differently

Hyl: But how, according to your views, do real things differ from chimeras formed by the imagination or the visions of a dream, since according to you they are all equally in the mind?

Phil: The ideas formed by the imagination are faint and indistinct; also, they are entirely dependent on the will. But the ideas perceived by sense—that is, real things—are more vivid and clear, and they don’t in that way depend on our will, because they are imprinted on our mind by a spirit other than us. So there’s no danger of mixing up these real things with the foregoing ideas formed by the imagination, and equally little danger of failing to distinguish them from the visions of a dream, which are dim, irregular, and confused. And even if dreams were very lively and natural, they could easily be distinguished from realities by their not being coherently connected with the preceding and subsequent episodes of our lives, In short, whatever method you use to distinguish things from chimeras is obviously available to me too. For any such method must, I presume, be based on some perceived difference, and I don’t want to deprive you of any one thing that you perceive.

Hyl: But still, Philonous, you hold that there is nothing in the world but spirits and ideas. You must admit that this sounds very odd.

Phil: I agree that the word ‘idea’, not being commonly used for ‘thing’, sounds a little peculiar. I used it because it implies a necessary relation to the mind; and it is now commonly used by philosophers to stand for the immediate objects of the understanding. But however odd the proposition may sound in words, there’s nothing very strange or shocking in what it means, which in effect amounts merely to this: that there are only perceiving things and perceived things; or that every unthinking being is necessarily—from the very nature of its existence—perceived by some mind, if not by any finite created mind then certainly by the infinite mind of God, in whom ‘we live, and move, and have our being’. Is this as strange as to say that sensible qualities aren’t in the objects? Or that we can’t be sure of the existence of things, or know anything of their real natures, although we see and feel them and perceive them by all our senses?

Hyl: Don’t we have to infer from this that there are no such things as physical or corporeal causes, but that a spirit is the immediate cause of all the phenomena in nature? Can there be anything more extravagant than this?

Phil: Yes, there can! It is infinitely more extravagant to say that an inert thing operates on the mind, and an unperceiving thing causes our perceptions. Anyway, the view that you for some reason find so extravagant is no more than the holy scriptures assert in a hundred places. In them God is represented as the sole and immediate cause of all those effects that some heathens and philosophers customarily attribute to nature, matter, fate, or some such unthinking agent. There is no need for me to support this with particular citations—scripture is full of it.

Hyl: You aren’t aware, Philonous, that in making God the immediate cause of all the motions in nature you make him the author of murder, sacrilege, adultery, and the like heinous sins.

Phil: In answer to that, I remark first that a person’s guilt is the same whether he performs an action with or without an instrument. So if you think that God acts through the mediation of an instrument or ‘occasion’ called matter, you make him the author of sin just as much as I do through my view that he is immediate agent in all those operations that common people ascribe to ‘nature’. I further remark that sin or wickedness does not consist in the outward physical action or movement, but in something internal—the will’s departing from the laws of reason and religion. This is clearly so, from the fact that killing an enemy in a battle or putting a criminal legally to death is not thought sinful, although the outward acts are exactly the same as in murder. Sin therefore doesn’t consist in the physical action, so making God an immediate cause of all such actions isn’t making him the author of sin. Lastly, I have nowhere said that God is the only agent who produces all the motions in bodies. True, I have denied there are any agents other than spirits; but this is quite consistent with assigning to thinking, rational beings the use of limited powers in the production of motions. These powers are indeed ultimately derived from God, but they are immediately under the direction of the beings’ own wills, and that is sufficient to entitle them to all the guilt of their actions.

Hyl: But denying matter, Philonous, or corporeal substance! There is the sticking point. You can never persuade me that this isn’t in conflict with the universal sense of mankind. If our dispute were to be settled by majority vote, I am confident that you would surrender without counting the votes.

Phil: I would like both our positions to be fairly stated and submitted to the judgment of men who had plain common sense, without the prejudices of a learned education. Let me be represented as one who trusts his senses, who thinks he knows the things he sees and feels, and has no doubts about their existence; and you fairly present yourself, armed with all your doubts, your paradoxes, and your scepticism; and I shall willingly accept the decision of any unbiased person. To me it is obvious that spirit is the only substance in which ideas can exist. And everyone agrees that the objects we immediately perceive are ideas. And no-one can deny that sensible qualities are objects that we immediately perceive. It is therefore evident there can’t be any substratum of those qualities; they can exist in a spirit, not as qualities of it but as things perceived by it. So I deny that there is any unthinking substratum of the objects of sense, and that is the meaning of my denial that there is any material substance. But if by ‘material substance’ is meant only sensible body, that which is seen and felt (and I dare say that unphilosophical people mean no more), then I am more certain of matter’s existence than you or any other philosopher claim to be. If there is anything that turns people in general off from the views that I support, it is the mistaken idea that I deny the reality of sensible things. But it is you who are guilty of that, not I, so what they are really hostile to are your notions, not mine. I do therefore assert—as something I am as certain of as I am of my own existence—that there are bodies or corporeal substances (meaning the things I perceive by my senses). Most people will agree with this, and will neither think nor care about the fate of those unknown natures and essences that some men are so fond of.

Hyl: What do you say to this? Since, according to you, men judge the reality of things by their senses, how can a man be mistaken in thinking that the moon is a plain shining surface, about a foot in diameter; or that a square tower seen at a distance is round; or that an oar with one end in the water is crooked?

Phil: He is mistaken not with regard to the ideas he actually perceives, but in what he infers from his present perceptions. Thus in the case of the oar, what he immediately perceives by sight is certainly crooked; and to that extent he is right. But if he infers from this that when he takes the oar out of the water he will see the same crookedness, or that it will affect his sense of touch as crooked things usually do, in that he is mistaken. Likewise, if from what he perceives in one place he infers that if he moves closer to the moon or tower he will still experience similar ideas, he is mistaken. But his mistake lies not in what he perceives immediately and at present (for it is a manifest contradiction to suppose he could err about that), but in the wrong judgment he makes concerning the ideas he thinks to be connected with the ones he immediately perceives; or concerning the ideas that—judging by what he perceives at present—he thinks would be perceived in other circumstances. The case is the same with regard to the Copernican system. We don’t perceive any motion of the earth while we are standing on it; but it would be wrong to infer from this that if we were placed at as great a distance from earth as we are now from the other planets we would not then perceive the earth’s motion.

Hyl: I understand you; and I have to admit that what you say is plausible enough. Still, let me remind you of something. Tell me, Philonous, weren’t you formerly as sure that matter exists as you are now that it does not?

Phil: I was. But here lies the difference. Before, my confidence was uncritically based on prejudice; but my confidence now, after enquiry, rests on evidence.

Hyl: After all, it seems that our dispute is about words rather than things. We agree in the thing, but differ in the name. It is obvious that we are affected with ideas from outside ourselves; and it is equally obvious that there must be powers outside the mind corresponding to those ideas (I don’t say resembling them). And as these powers can’t exist by themselves, we have to postulate some subject of them—some thing that has the powers—which I call ‘matter’, and you call ‘spirit’. This is all the difference.

Phil: Hylas, is that powerful being, or subject of powers, extended?

Hyl: It isn’t; but it has the power to cause the idea of extension in you.

Phil: In itself, therefore, it is unextended.

Hyl: I grant it.

Phil: Is it not also active?

Hyl: Without doubt: otherwise, how could we attribute powers to it?

Phil: Now let me ask you two questions. First, does it conform to the usage of philosophers or of non-philosophers to give the name ‘matter’ to an unextended active being? Second, isn’t it ridiculously absurd to misapply names contrary to the common use of language?

Hyl: Well, then, let it not be called ‘matter’, since you insist, but some third nature distinct from matter and spirit. For, what reason do you have to call it ‘spirit’? Doesn’t the notion of spirit imply that it is thinking as well as active and unextended?

Phil: My reason is as follows. I want to have some notion or meaning in what I say; but I have no notion of any action other than volition, and I can’t conceive of volition as being anywhere but in a spirit; so when I speak of an active being, I am obliged to mean a spirit. Besides, it is quite obvious that a thing that can impart ideas to me must have ideas in itself; and if a thing has ideas, surely it must be a spirit. I shall state the case differently, to enable you to understand the point still more clearly, if that is possible. I assert, as you do, that since we are affected from outside ourselves we must accept that there are powers outside us in some being that is distinct from ourselves. Up to here we are in agreement; but then we differ about what kind of powerful being it is. I say it is spirit; you say that it is matter or else some third kind of thing—I don’t know of what kind, and nor do you! Here is how I prove it to be spirit. From the effects I see produced, I infer that there are actions; so there are volitions; so there must be a will. Again, the things I perceive (or things they are copied from) must exist outside my mind: but because they are ideas, neither they nor things they are copied from can exist otherwise than in an understanding; there is therefore an understanding. But will and understanding constitute in the strictest sense a mind or spirit. The powerful cause of my ideas is, therefore, something that it is strictly proper to call ‘a spirit’.

Hyl: I suppose you think you have made the point very clear, little suspecting that what you propose leads directly to a contradiction. It is an absurdity to imagine any imperfection in God, is it not?

Phil: Without doubt.

Hyl: To suffer pain is an imperfection.

Phil: It is.

Hyl: Are we not sometimes affected with pain and discomfort by some being other than ourselves?

Phil: We are.

Hyl: And haven’t you said that that being is a spirit, and is not that spirit God?

Phil: I agree.

Hyl: But you have asserted that any ideas that we perceive from outside ourselves are in the mind that affects us. It follows that the ideas of pain and discomfort are in God; or, in other words, God suffers pain. That is to say that there is an imperfection in the divine nature, which you agreed was absurd. So you are caught in a plain contradiction.

Phil: I don’t question that God knows or understands all things, including knowing what pain is; he even knows every sort of painful sensation, and what it is for his creatures to suffer pain. But I positively deny that God, though he knows and sometimes causes painful sensations in us, can himself suffer pain. We who are limited and dependent spirits are liable to sensory impressions—caused by an external agent and produced against our wills—that are sometimes painful and distressing. But God cannot suffer anything, or be affected with any painful sensation, or indeed with any sensation at all, because: no external being can affect him, he perceives nothing by sense as we do, his will is absolute and independent, causing all things and incapable of being thwarted or resisted by anything. We are chained to a body; that is to say, our perceptions are connected with bodily motions. By the law of our nature we undergo changes in our minds with every alteration in the nervous parts of our sensible [= ‘perceptible’] body; this sensible body is really nothing but a complex of qualities or ideas that have no existence other than through being perceived by a mind; so that this connection of sensations with bodily motions comes down to a mere correspondence in the order of nature between two sets of ideas or immediately perceivable things—the set of ideas perceived by someone’s mind, and the set constituting his body. In contrast with this, God is a pure spirit, disengaged from all such correspondences or linkages according to laws of nature. No bodily motions are accompanied by sensations of pain or pleasure in his mind. To know everything knowable is certainly a perfection; but to endure, or suffer, or feel anything through the senses is an imperfection. The former, I repeat, fits God, but not the latter. God knows or has ideas; but his ideas aren’t conveyed to him by sense as ours are. What led you to think you saw an absurdity where really there is none was your failure to attend to this obvious difference between God and his creatures.

Hyl: There is a well established scientific result which implies the existence of matter, and you have ignored it. Throughout all this you haven’t considered the fact that the quantity of matter has been demonstrated [= ‘rigorously proved’] to be proportional to the gravity of bodies. And what can stand up against the force of a demonstration?

Phil: Let me see how you demonstrate that point.

Hyl: I lay it down for a principle that the quantities of motion in bodies are directly proportional to their velocities and the quantities of matter contained in them. When the velocities of two bodies are equal, therefore, their quantities of motion are directly proportional to the quantity of matter in each. But it has been found by experience that all bodies (not counting small inequalities arising from the resistance of the air) fall with an equal velocity; and so the motion of falling bodies (and consequently their gravity, which is the cause or source of that motion) is proportional to the quantity of matter they contain; which is what I was to demonstrate.

Phil: You lay it down as a self-evident principle that the quantity of motion in any body is proportional to the velocity and matter taken together; and this is used to prove a proposition from which the existence of matter is inferred. Isn’t this arguing in a circle?

Hyl: In the premise I only mean that the motion is proportional to the velocity jointly with the extension and solidity, so I don’t need to use the term ‘matter’ in the premise.

Phil: But even if this is true, it doesn’t imply that gravity is proportional to matter in your philosophical sense of the word. To get that conclusion you have to take it for granted in your premise that your unknown substratum or whatever else you call it is proportional to those sensible qualities (velocity and quantity of motion); but to suppose that is plainly assuming what was to be proved. I readily grant that there is size and solidity (or resistance) perceived by the senses; and I shan’t dispute the claim that gravity is proportional to those qualities. What I do deny is that these qualities as perceived by us, or the powers producing them, exist in a material substratum. You affirm this, but despite your ‘demonstration’ you haven’t yet proved it.

Hyl: I shan’t press that point any further. Do you expect, though, to persuade me that natural scientists have been dreaming all through the years? What becomes of all their hypotheses and explanations of the phenomena, which presuppose the existence of matter?

Phil: What do you mean by ‘the phenomena’?

Hyl: I mean the appearances that I perceive by my senses.

Phil: And the appearances perceived by the senses—aren’t they ideas?

Hyl: I have told you so a hundred times.

Phil: Therefore, to ‘explain the phenomena’ is to show how we come to be affected with ideas in the particular manner and order in which they are imprinted on our senses. Is it not?

Hyl: It is.

Phil: Now, if you can prove that any scientist has explained the production of any one idea in our minds with the help of matter, I shall capitulate, and regard all that I have said against matter as nothing; but if you can’t, you will get nowhere by urging the explanation of phenomena. It is easy to understand that a being endowed with knowledge and will should produce or display ideas; but I can never understand how a being that is utterly destitute of knowledge and will could produce ideas or in any way to affect a mind. Even if we had some positive conception of matter, knew its qualities, and could comprehend its existence, it would still be so far from explaining things that it would itself be the most inexplicable thing in the world. From all this, however, it doesn’t follow that scientists have been doing nothing; for by observing and reasoning about connections of ideas they discover the laws and methods of nature, which is a useful and interesting branch of knowledge.

Hyl: All the same, can it be supposed God would deceive all mankind? Do you imagine that he would have induced the whole world to believe in the existence of matter if there was no such thing?

Phil: I don’t think you will affirm that every widespread opinion arising from prejudice, or passion, or thoughtlessness, may be blamed on God as the author of it. We aren’t entitled to lay at his door an opinion of ours unless either he has shown it to us by supernatural revelation or it is so evident to our natural faculties, which were formed and given to us by God, that we couldn’t possibly withhold our assent from it. But where is the supernatural revelation of matter, or where is the evidence that compels us to believe in it? Indeed, what is the evidence that matter, taken for something distinct from what we perceive by our senses, is thought to exist by all mankind, or indeed by any except a few philosophers who don’t know what they are saying? Your question presupposes that these points are clear. When you have made them so, I shall regard myself as obliged to give you another answer. In the meantime let it suffice that I tell you that I don’t suppose that God has deceived mankind at all.

Hyl: But the novelty, Philonous, the novelty! There lies the danger. New notions should always be discouraged; they unsettle men’s minds, and nobody knows what they will lead to.

Phil: I can’t imagine why rejecting a notion that has no basis in sense, or in reason, or in divine authority, should be thought to unsettle men’s hold on beliefs that are grounded on all or any of these. I freely grant that new opinions about government and religion are dangerous, and ought to be discountenanced. But is there any such reason why they should be discouraged in philosophy? Making anything known that was unknown before introduces a new opinion; and if all such new opinions had been forbidden, what a notable progress men would have made in the arts and sciences! But it isn’t my concern to plead for novelties and paradoxes.

That the qualities we perceive are not in the objects;

that we mustn’t believe our senses;

that we know nothing of the real nature of things, and can never be assured even that they exist;

that real colours and sounds are nothing but certain unknown shapes and motions;

that motions are in themselves neither swift nor slow;

that bodies have absolute extensions, without any particular size or shape;

that a stupid, thoughtless, and inactive thing operates on a spirit;

that the tiniest particle of a body contains countless extended parts.

These are the novelties, these are the strange notions which shock the genuine uncorrupted judgment of all mankind and, having once been accepted, embarrass the mind with endless doubts and difficulties. And it is against these and their like that I try to vindicate common sense. It is true that in doing this I may have to express myself in some roundabout ways and to use uncommon turns of speech; but once my notions are thoroughly understood, what is strangest in them will be found to come down merely to this: It is absolutely impossible, and a plain contradiction to suppose, that any unthinking being should exist without being perceived by a mind. And if this view is found to be strange, it is a shame that it should be so in our age and in a Christian country.

Hyl: I shan’t question what you say about the difficulties that other opinions may be liable to; but it is your business to defend your own opinion. Can anything be more obvious than that you support changing all things into ideas? Yes, you, who are not ashamed to charge me with scepticism! This is so obvious that there is no denying it.

Phil: You have me wrong. What I support is not changing things into ideas, but rather ideas into things; since those immediate objects of perception which you say are only appearances of things are what I take to be the real things themselves.

Hyl: Things! Say what you like, it’s certain that all you leave us with are the empty forms of things, their mere outsides that strike the senses.

Phil: What you call the ‘empty forms’ and ‘outsides’ of things seem to me to be the things themselves. And they aren’t empty or incomplete, except on your supposition that matter is an essential part of all bodily things. So you and I agree that we perceive only sensible forms; but we differ in that you maintain them to be empty appearances, while I think they are real beings. In short, you don’t trust your senses, I do trust mine.

Hyl: You say that you believe your senses, and you seem to congratulate yourself on agreeing with common people about this. According to you, therefore, the true nature of a thing is discovered by the senses. If so, what is the source of the sensory disagreement that we experience? Why do different ways of perceiving—e.g. sight and touch—indicate different shapes for the same object? And if the true nature of a body can be discovered by the naked eye, why should a microscope enable us to know it better?

Phil: Strictly speaking, Hylas, we don’t see the same object that we feel; and the object perceived through the microscope isn’t the same one that was perceived by the naked eye. But if every variation were thought sufficient to constitute a new kind or new individual, language would be made useless by the sheer number of names or by confusions amongst them. Therefore, to avoid this and other inconveniences (you’ll easily see what they are if you think about it), men in their thought and language treat as one thing a number of ideas that are observed to have some connection in nature (either occurring together or in sequence), although the ideas are certainly distinct from one another, because they are perceived through different senses, or through one sense at different times or in different circumstances. So when I see a thing and then proceed to examine it by my other senses, I’m not trying to understand better the same object that I had seen. That can’t be what I am doing, because the object of one sense can’t be perceived by the other senses. And when I look through a microscope, it isn’t so as to perceive more clearly what I had already perceived with my bare eyes, because the objects perceived in these two ways are quite different from one another. In each case, all I want is to know what ideas are connected together; and the more a man knows of the connection of ideas the more he is said to know of the nature of things. If our ideas are variable, and our senses are not always affected with the same appearances—what of it? It doesn’t follow that they aren’t to be trusted, or that they are inconsistent either with themselves or with anything else, except for your preconceived notion that each name stands for I know not what single, unchanged, unperceivable ‘real nature’; a prejudice that seems to have arisen from a failure to understand the common language that people use when speaking of several distinct ideas as united into one thing by the mind. There is reason to suspect that other erroneous views of the philosophers are due to the same source: they founded their theories not so much on notions as on words, which were invented by the common people merely for convenience and efficiency in the common actions of life, without any regard to theories.

Hyl: I think I follow you.

Phil: You hold that the ideas we perceive by our senses are not real things but images or copies of them. So our knowledge is real only to the extent that our ideas are the true representations of those originals. But as these supposed originals (or real things) are in themselves unknown, we can’t know how far our ideas resemble them, or indeed whether they resemble them at all. So we can’t be sure that we have any real knowledge. Furthermore, while the supposed real things remain unchanged our ideas keep changing; so they can’t all be true copies of the real things; and if some are and others are not, we can’t tell which are which. This plunges us yet deeper into uncertainty. Again, when we think about it we can’t conceive how any idea, or anything like an idea, could have an absolute existence out of any mind; from which it follows, according to your views, that we can’t conceive how there should be any real thing in nature because you say that real things are like ideas. The result of all this is that we are hopelessly lost in scepticism. Now let me ask you four questions. First, doesn’t all this scepticism arise from your relating ideas to certain absolutely existing unperceived substances, as their originals? Secondly, are you informed, either by sense or reason, of the existence of those unknown originals? And if you are not, isn’t it absurd to suppose that they exist? Thirdly, when you look into it, do you find that there is anything distinctly conceived or meant by the absolute or external existence of unperceiving substances? Lastly, having considered the premises that I have put to you, isn’t it wisest to follow nature, trust your senses, lay aside all anxious thoughts about unknown natures or substances, and join the common people in taking the things that are perceived by the senses to be real things?

Hyl: Just now I am not inclined to answer your questions. I would much rather see how you can answer mine. Aren’t the objects perceived by one person’s senses also perceivable by others who are present? If there were a hundred more people here, they would all see the garden, the trees, and flowers as I see them. But they don’t experience in the same way the ideas that I form in my imagination. Doesn’t this make a difference between the former sort of objects and the latter?

Phil: I agree that it does; and I have never denied that the objects of sense are different from those of imagination. But what would you infer from this? You can’t say that sensible objects exist unperceived because they are perceived by many people.

Hyl: I admit that I can’t make anything of that objection of mine; but it has led me to another. Isn’t it your opinion that all we perceive through our senses are the ideas existing in our minds?

Phil: It is.

Hyl: But the idea that is in my mind can’t be in yours, or in any other mind. So doesn’t it follow from your principles that no two people can see the same thing? And isn’t this highly absurd?

Phil: If the term ‘same’ be given its common meaning, it is certain (and not at all in conflict with the principles I maintain) that different persons may perceive the same thing; and that the same thing or idea can exist in different minds. The meanings of words are assigned by us; and since men customarily apply the word ‘same’ where no distinction or variety is perceived, and I don’t claim to alter their perceptions, it follows that as men have sometimes said ‘Several people saw the same thing’, they may continue to talk like that in similar situations, without deviating either from correctness of language or the truth of things. But if the term ‘same’ is used in a meaning given to it by philosophers who claim to have an abstracted notion of identity, then in that sense it may or may not be possible for different people to perceive the same thing—depending on their various definitions of this notion (for it isn’t yet agreed what that philosophical identity consists in). But whether philosophers shall think fit to call a thing ‘the same’ or not is of small importance, I think. Let us suppose a group of men together, all having the same faculties and consequently affected in similar ways by their senses, but with no use of language. There is no doubt that they would agree in their perceptions. But when they came to the use of speech, they might go different ways in their use of ‘same’. Some of them, impressed by the uniformness of what was perceived, might speak of ‘the same thing’; while others, struck by the diversity of the people whose perceptions were in question, might speak of ‘different things’. But can’t anyone see that all the dispute is about a word—namely, a dispute over whether what is perceived by different people can have the term ‘same’ applied to it? Or suppose a house whose outer walls remain unaltered while the rooms are all pulled down and new ones built in their place. If you were to say that we still have ‘the same’ house, and I said it wasn’t the same, wouldn’t we nevertheless perfectly agree in our thoughts about the house considered in itself? Wouldn’t all the difference consist in a sound? If you were to say that in that case we do differ in our notions, because your idea of the house includes the simple abstracted idea of identity whereas mine does not, I would tell you that I don’t know what you mean by that ‘abstracted idea of identity’; and I would invite you to look into your own thoughts, and make sure that you understood yourself.—Why so silent, Hylas? Aren’t you satisfied yet that men can dispute about identity and non-identity without any real difference in their thoughts and opinions, apart from names? Take this further thought with you: that this point still stands, whether matter exists or not. For the materialists themselves admit that what we immediately perceive by our senses are our own ideas. So your difficulty—that no two see the same thing—holds as much against the materialists as against me.

Hyl: But they suppose that an idea represents and copies an external thing, and they can say truly that several people ‘perceive the same thing’ meaning that their ideas all copy a single external thing.

Phil: You earlier gave up on those things that ideas were said to copy; but let that pass. Anyway, on my principles also you can suppose that ideas are copies of something external, by which I mean external to one’s own mind, though indeed it must be supposed to exist in that mind which includes all things. This thing-that-is-copied serves all the ends of identity—providing a basis for saying ‘they perceived the same thing’—as well as if it existed out of a mind. And I am sure you won’t say that it is less intelligible than the other.

Hyl: You have indeed clearly satisfied me that there is basically no difficulty in this point; or that if there is, it counts equally against both opinions.

Phil: But something that counts equally against two contradictory opinions can’t be a disproof of either of them.

Hyl: I agree. But after all, Philonous, when I consider the substance of what you say against scepticism, it amounts to no more than this: We are sure that we really see, hear, feel; in a word, we are sure that we are affected with sensible impressions.

Phil: And what more should we be concerned with? I see this cherry, I feel it, I taste it; and I am sure nothing cannot be seen, or felt, or tasted; so the cherry is not nothing and it is therefore real. Take away the sensations of softness, moisture, redness, tartness, and you take away the cherry. Since it is not a thing distinct from sensations, a cherry—I repeat—is nothing but a heap of sensible impressions, or ideas perceived by various senses. These ideas are united into one thing (or have one name given to them) by the mind, because they are observed to accompany each other. Thus when the palate is affected with a certain taste, the sight is affected with a red colour, the sense of touch with roundness, softness, etc. And when I see and feel and taste in certain particular ways, I am sure that the cherry exists, or is real; because I don’t think its reality is anything apart from those sensations. But if by the word ‘cherry’ you mean an unknown nature distinct from all those sensible qualities, and by its ‘existence’ you mean something distinct from its being perceived, then indeed I agree that neither you nor I nor anyone else can be sure that it exists.

Hyl: But what would you say, Philonous, if I brought the very same reasons against the existence of sensible things in a mind that you have offered against their existing in a material substratum?

Phil: When I see your reasons I’ll tell you what I have to say to them.

Hyl: Is the mind extended or unextended?

Phil: Unextended, without doubt.

Hyl: Do you say the things you perceive are in your mind?

Phil: They are.

Hyl: Again, have I not heard you speak of sensible impressions?

Phil: I believe you may have.

Hyl: Explain to me now, Philonous, how there can possibly be room for all those trees and houses to exist in your mind! Can extended things be contained in something that has no size because it is unextended? And are we to imagine impressions made on a thing that has no solidity? Obviously not! You can’t say that objects are in your mind as books are in your study; or that things are impressed or imprinted on your mind as the shape of a seal is imprinted on wax. In what sense therefore are we to understand those expressions? Explain this to me if you can; and I shall then be able to answer all those questions you earlier put to me about my substratum.

Phil: Come on, Hylas! When I speak of objects as existing ‘in’ the mind or ‘imprinted’ on the senses, I don’t mean these in the crude literal sense, as when bodies are said to exist ‘in’ a place or a seal to make an ‘impression’ on wax. I mean only that the mind comprehends or perceives them; and that it is affected from outside, or by some being other than itself. This is my explanation of your difficulty; I would like to know how it can help to make intelligible your thesis of an unperceiving material substratum.

Hyl: No, if that’s all there is to it, I admit that I don’t see what use can be made of it. But are you not guilty of some misuse of language in this?

Phil: None at all. I have merely followed what is authorized by common custom, which as you know is what sets the rules for language. For nothing is more usual than for philosophers to speak of the immediate objects of the understanding as things existing ‘in’ the mind. And this fits with the general analogy of language: most mental operations are signified by words borrowed from sensible things, as can be seen in the terms ‘comprehend’ [contain, understand], ‘reflect’ [bounce back, look inward], ‘discourse’, etc.. When these are applied to the mind, they must not be taken in their crude original sense. [The word ‘discourse’ comes from Latin meaning ‘run to and fro’, and in Berkeley’s day it could mean ‘reasoning’.]

Hyl: You have, I admit, satisfied me about this. But there still remains one great difficulty, which I don’t see how you can overcome. Indeed, it is of such importance that even if you can solve all others, if you can’t find a solution for this difficulty you mustn’t expect to make a convert out of me.

Phil: Let me know this mighty difficulty.

Hyl: The scriptural account of the creation appears to me to be utterly incompatible with your notions. Moses tells us of a creation: a creation of what? of ideas? No, certainly, but of things, of real things, solid corporeal substances. Get your principles to conform with this and I shall perhaps agree with you about them in general.

Phil: Moses mentions the sun, moon, and stars, earth and sea, plants and animals: I don’t question that all these do really exist, and were in the beginning created by God. If by ‘ideas’ you mean fictions and fancies of the mind, then the sun, moon, etc. are no ideas. If by ‘ideas’ you mean immediate objects of the understanding, or sensible things that can’t exist unperceived or out of a mind, then those things are ideas. But it matters little whether you call them ‘ideas’ or not. That difference is only about a name. And whether that name be retained or rejected, the sense, the truth and reality of things, continues the same. In common talk, the objects of our senses are not called ‘ideas’, but ‘things’. You’ll have no quarrel with me if you go on calling them ‘things’, provided you don’t attribute to them any absolute external existence. So I accept that the creation was a creation of things, of real things. This isn’t in the least inconsistent with my principles, as is evident from what I have just been saying, and would have been evident to you without that, if you hadn’t forgotten what I so often said before. As for solid corporeal substances, please show where Moses makes any mention of them; and if they should be mentioned by him or any other inspired writer, it would still be up to you to show that in such texts those words were not used in the common meaning, as referring to things falling under our senses, but in the philosophical meaning as standing for matter, or an unknown something, with an absolute mind-independent existence. When you have proved these points, then (and not till then) you may bring the authority of Moses into our dispute.

Hyl: It is useless to dispute about a point that is so clear. I am content to refer it to your own conscience. Can’t you see that your views conflict in a special way with Moses’ account of the creation?

Phil: If the first chapter of Genesis can be given any possible sense that makes it square with my principles as well as with any others, then that chapter has no special conflict with mine. And any such sense can be conceived by you, because you believe what I believe. All you can conceive apart from spirits are ideas, and their existence I don’t deny. And you like me don’t claim that they exist outside the mind.

Hyl: Please let me see any sense in which you can understand that chapter.

Phil: Why, I imagine that if I had been present at the creation, I would have seen things come into existence—that is, become perceptible—in the order described by Moses. I have always believed Moses’ account of the creation, and I don’t find that my manner of believing it has altered in any way. When things are said to begin or end their existence, we mean this with regard not to God but to his creatures. All objects are eternally known by God, or (the same thing) have an eternal existence in his mind; but when things that were previously imperceptible to creatures are by a decree of God made perceptible to them, then are they said to ‘come into existence’, in the sense that they begin a relative existence with respect to created minds. So when I read Moses’ account of the creation, I understand that the various parts of the world gradually became perceivable to finite spirits that were endowed with proper faculties; so that when such spirits were present, the things were in truth perceived by them. This is the literal, obvious sense suggested to me by the words of the holy scripture; and in it there is no mention and no thought of substratum, instrument, occasion, or absolute existence. And if you look into it I am sure you will find that most plain, honest men who believe the creation never think of those things any more than I do. What metaphysical sense you may understand the creation story in, only you can tell.

Hyl: But, Philonous, you seem not to be aware of a terrific problem confronting you, arising from the fact that according to you created things in the beginning had only a relative existence, and thus a hypothetical existence; that is to say, they existed if there were men to perceive them. You don’t allow them any actuality of absolute existence that would have enabled God to create them and not taken the further step of creating men. So don’t you have to say that it’s plainly impossible that inanimate things were created before man was? And isn’t this directly contrary to Moses’ account?

Phil: In answer to that I say, first, created beings might begin to exist in the mind of other created intelligences besides men. To prove any contradiction between Moses’ account and my notions you must first show that there was no other order of finite created spirits in existence before men. For my second reply, let us think of the creation as it was at the end of the fourth day, a collection of plants of all sorts, produced by an invisible power, in a desert where nobody was present. I say that this way of thinking about the creation is consistent with my principles, since they deprive you of nothing sensible and nothing imaginable; that it exactly suits with the common, natural, uncorrupted notions of mankind; that it brings out the dependence of all things on God, and consequently has all the good effect or influence which that important article of our faith could possibly have in making men humble, thankful, and resigned to their creator. I say, furthermore, that in this naked conception of things, with words stripped off, you won’t find any notion of what you call the ‘actuality of absolute existence’. You may indeed raise a dust with those terms, and so pointlessly lengthen our dispute. But I beg you to look calmly into your own thoughts, and then tell me if they aren’t useless and unintelligible jargon.

Hyl: I admit that I have no very clear notion annexed to them. But what do you say to this? Don’t you make the existence of sensible things consist in their being in a mind? And weren’t all things eternally in the mind of God? Didn’t they therefore exist from all eternity, according to you? How could something that was eternal be created in time? Can anything be clearer or better reasoned than this?

Phil: Don’t you also think that God knew all things from eternity?

Hyl: I do.

Phil: Consequently they always had an existence in the divine intellect.

Hyl: This I acknowledge.

Phil: By your own admission, therefore, nothing is new, nothing begins to be, in respect of the mind of God. So we are agreed on that point.

Hyl: Then what are we to make of the creation?

Phil: Can’t we understand it to have been entirely in respect of finite spirits? On that understanding of it, things (with regard to us) can properly be said to begin their existence, or be created, when God decreed they should become perceptible to intelligent creatures in the order and manner which he then established and which we now call ‘the laws of nature’. You may call this a relative or hypothetical existence if you please. But so long as it supplies us with the most natural, obvious, and literal sense of Moses’ history of the creation; so long as it answers all the religious ends of that great article of faith; in a word, so long as you can assign no other sense or meaning in place of it; why should we reject this? Is it to comply with a ridiculous sceptical desire to make everything nonsense and unintelligible? I am sure you can’t say it is for the glory of God. For even if it were possible and conceivable that the physical world should have an absolute existence outside the mind of God, as well as of the minds of all created spirits, how could this display either the immensity or the omniscience of the Deity, or the necessary and immediate dependence of all things on him? Wouldn’t it indeed seem rather to detract from those attributes?

Hyl: Well, let us look into this decree of God’s that things should become perceptible. Isn’t it clear, Philonous, that either God carried out that decree from all eternity or at some particular time he began to will what he hadn’t actually willed before but only planned to will? If the former, then there could be no creation or beginning of existence for finite things. If the latter, then we must think that something new happened to God, which implies a sort of change; and all change points to imperfection.

Phil: Please think what you are doing! Isn’t it obvious that this objection counts equally against a creation in any sense; indeed, that it counts against every other act of God’s that we can discover by the light of nature? We can’t conceive any act of God’s otherwise than as performed in time, and having a beginning. God is a being of transcendent and unlimited perfections; so finite spirits can’t understand his nature. It isn’t to be expected, therefore, that any man, whether materialist or immaterialist, should have exactly correct notions of the Deity, his attributes, and his ways of doing things. So if you want to infer anything against me, your difficulty mustn’t be drawn from the inadequateness of our conceptions of the divine nature, which is unavoidable on any system; it must rather come from my denial of matter, of which there isn’t one word said or hinted in what you have just objected.

Hyl: I have to agree that the only difficulties you have to clear up are ones that arise from the non-existence of matter, and are special to that thesis. You are right about that. But I simply can’t bring myself to think there is no such special conflict between the creation and your opinion; though I am not clear about where exactly it is.

Phil: What more do you want? Don’t I acknowledge a twofold state of things, the one copied or natural, the other copied-from and eternal? The former was created in time; the latter existed from everlasting in the mind of God. Isn’t this in harmony with what theologians generally say? Is anything more than this necessary in order to conceive the creation? But you suspect some special conflict, though you cannot locate it. To take away all possibility of doubt about all this, just consider this one point. Either you can’t conceive the creation on any hypothesis whatsoever, in which case you have no ground for dislike or complaint against my thesis in particular; or you can conceive the creation, and in that case why not conceive it on my principles, since that would not take away anything conceivable? My principles have all along allowed you the full scope of sense, imagination, and reason. So anything that you could previously apprehend, either immediately by your senses or mediately by inferences from your senses, anything you could perceive, imagine, or understand, remains still with you on my principles. If therefore the notion you have of the creation by other principles is intelligible, you still have it on mine; if it isn’t intelligible, I don’t think it is a notion at all, and so the loss of it is no loss. And indeed it seems to me quite clear that the supposition of matter—something perfectly unknown and inconceivable—can’t enable us to conceive anything. And I hope I don’t need to prove to you that the inference from The creation is inconceivable without matter to Matter exists is no good if the existence of matter doesn’t make the creation conceivable.

Hyl: I admit, Philonous, you have almost satisfied me on this point of the creation.

Phil: I wonder why you aren’t entirely satisfied. You tell me indeed of an inconsistency between Moses’ history and immaterialism; but you don’t know where it lies. Is this reasonable, Hylas? Can you expect me to solve a difficulty without knowing what it is? But setting that aside, wouldn’t anyone think you are sure that the received notions of materialists are consistent with holy scripture?

Hyl: And so I am.

Phil: Ought the historical part of scripture to be understood in a plain, obvious sense, or in a sense that is metaphysical and out of the way?

Hyl: In the plain sense, doubtless.

Phil: When Moses speaks of ‘plants’, ‘earth’, ‘water’, etc. as having been created by God, don’t you think that what this suggests to every unphilosophical reader are the sensible things commonly signified by those words?

Hyl: I can’t help thinking so.

Phil: And doesn’t the doctrine of materialists deny a real existence to all ideas, that is, all things perceived by sense?

Hyl: I have already agreed to this.

Phil: According to them, therefore, the creation was not the creation of sensible things that have only a relative existence, but of certain unknown natures that have an absolute existence—so that they could exist even if there were no spirit to perceive them.

Hyl: True.

Phil: Isn’t it evident, therefore, that the friends of matter destroy the plain obvious sense of Moses, with which their notions are utterly inconsistent; and instead of it force on us I know not what, something equally unintelligible to themselves and me?

Hyl: I can’t contradict you.

Phil: Moses tells us of a creation. A creation of what? of unknown essences, of occasions, or substratums? No, certainly; but of things that are obvious to the senses. You must first reconcile this with your notions, if you want me to be reconciled to them.

Hyl: I see you can attack me with my own weapons.

Phil: Then as to absolute existence: was there ever known a more poverty-stricken notion than that? It is something so abstracted and unintelligible that you have frankly admitted to being unable to conceive it, much less to explain anything with its help. But even if we allow that matter exists and that the notion of absolute existence is as clear as daylight, has this ever been known to make the creation more credible? On the contrary, hasn’t it provided the atheists and infidels down through the centuries with their most plausible argument against a creation? This thesis:

A corporeal substance which has an absolute existence outside the minds of spirits was produced out of nothing by the mere will of a spirit,

has been seen as so contrary to all reason, so impossible and absurd, that not only the most celebrated among the ancients, but even a variety of modern and Christian philosophers, have thought matter not to have been created at all, but to have existed for ever along with God. Put these points together, and then judge whether materialism disposes men to believe in the creation of things!

Hyl: I admit, Philonous, that I don’t think it does. This creation objection is the last one I can think of; and I have to admit that you have sufficiently answered it along with the rest. All that remains for me to overcome is a sort of unaccountable resistance that I find in myself towards your notions.

Phil: When a man is swayed to one side of a question, without knowing why, don’t you think that this must be the effect of prejudice, which always accompanies old and rooted notions? In this respect, indeed, I can’t deny that the belief in matter has very much the advantage over the contrary opinion, in the minds of educated men.

Hyl: I admit that that seems to be right.

Phil: Well, then, as a counter-balance to this weight of prejudice, let us throw into the scale the great advantages that arise from the belief in immaterialism, in regard to both religion and human learning. The existence of a God, and the imperishable nature of the soul, those great articles of religion, aren’t they proved with the clearest and most immediate evidence? When I say the existence of a God, I don’t mean an obscure, general cause of things, of which we have no conception, but God in the strict and proper sense of the word. A being whose spirituality, omnipresence, providence, omniscience, infinite power and goodness are as conspicuous as the existence of sensible things, of which (despite the fallacious claims and pretended doubts of sceptics) there is no more reason to doubt than of our own existence. Then with relation to human knowledge, in natural science what intricacies, what obscurities, what contradictions, has the belief in matter led men into! To say nothing of the numberless disputes about its extent, continuity, homogeneity, gravity, divisibility, etc., don’t they claim to explain everything in terms of bodies operating on bodies according to the laws of motion? And yet can they understand how one body might move another? Furthermore, even if there were no difficulty in

reconciling the notion of an inert being such as matter with the notion of a cause;

or in

conceiving how a quality might pass from one body to another (this being one theory about how one body can move another, namely by passing some motion along to it);

yet by all their strained thoughts and extravagant suppositions have the materialists been able to understand the mechanical production of any one animal or plant body? Can they through the laws of motion account for sounds, tastes, smells, or colours, or for the regular course of events? Have they through physical principles accounted for the intricate ways in which even the most inconsiderable parts of the universe hang together? If on the other hand we set aside matter and corporeal causes, and admit only the effectiveness of an all-perfect mind, don’t all the effects of nature become easy and intelligible? If the phenomena are nothing but ideas, the choice is obvious: God is a spirit, but matter is unintelligent and unperceiving. If the phenomena point to an unlimited power in their cause: God is active and omnipotent, but matter is an inert mass. If the order, regularity, and usefulness of the effects of nature can never be sufficiently admired: God is infinitely wise and provident, but matter doesn’t have plans and designs. These surely are great advantages in physics. Not to mention that the belief in a distant God naturally disposes men to be slack in their moral actions, which they would be more cautious about if they thought God to be immediately present and acting on their minds without the interposition of matter or unthinking ‘second causes’. Then in metaphysics: what difficulties concerning

thinghood in the abstract,

substantial forms,

‘hylarchic principles’,

‘plastic natures’,

substance and accident,

principle of individuation,

the possibility of matter’s thinking,

the origin of ideas,

the question of how two independent substances as widely different as spirit and matter could act on each other!

What difficulties, I say, and what endless treatises concerning these and countless other similar points do we escape by supposing only spirits and ideas? Even mathematics becomes much easier and clearer if we take away the absolute existence of extended things. The most shocking paradoxes and intricate speculations in the mathematical sciences depend on the infinite divisibility of finite extended things, and that depends on the supposition of absolutely existing extended things. But what need is there to insist on particular sciences? Isn’t the opposition to all systematic knowledge whatsoever—that frenzy of the ancient and modern sceptics—built on the same foundation? Can you produce so much as one argument against the reality of bodies, or on behalf of that professed utter ignorance of their natures, which doesn’t presuppose that their reality consists in an external absolute existence? Once that presupposition is made, the objections from the change of colours in a pigeon’s neck, or the broken appearance of an oar in the water, do have weight. But objections like those vanish if we don’t maintain the existence of absolute external originals, but place the reality of things in ideas. Although these ideas are fleeting and changeable, they are changed not at random but according to the fixed order of nature. For it is thatthe orderliness of our sequences of ideas—that the constancy and truth of things consists in. That is what secures all the concerns of life, and distinguishes what is real from the irregular visions of the imagination.

Hyl: I agree with everything you’ve just said, and must admit that nothing can incline me to embrace your opinion more than the advantages that I see come with it. I am by nature lazy, and this [= accepting immaterialism] would greatly simplify knowledge. What doubts, what hypotheses, what labyrinths of confusion, what fields of disputation, what an ocean of false learning, can be avoided by that single notion of immaterialism!

Phil: Is there now anything further to be done? You may remember that you promised to accept whatever opinion appeared on examination to be the most agreeable to common sense and furthest from scepticism. This, by your own admission, is the opinion that denies matter, or the absolute existence of bodily things. And we have gone further: this opinion has been proved in several ways, viewed from different angles, pursued in its consequences, and defended against all objections to it. Can there be a greater evidence of its truth? or could it have all the marks of a true opinion and yet be false?

Hyl: I admit that right now I am entirely satisfied in all respects. But how can I be sure that I shall go on fully assenting to your opinion, and that no new objection or difficulty will turn up?

Phil: Tell me, Hylas, when in other cases a point has been clearly proved, do you withhold your assent on account of objections or difficulties it may be liable to? When you are confronted with a mathematical demonstration [= ‘rigorously valid proof’], do you hold out against it because of the difficulties involved in the doctrine of incommensurable quantities, of the angle of contact, of the asymptotes to curves, or the like? Or will you disbelieve the providence of God because there are some particular things which you don’t know how to reconcile with it? If there are difficulties in immaterialism, there are at the same time direct and evident proofs of it. But for the existence of matter there isn’t a single proof, and there are far more numerous and insurmountable objections count against it. Anyway, where are those mighty difficulties you insist on? Alas! you don’t know where or what they are; they’re merely something that may possibly turn up in the future. If this entitles you to withhold your full assent, you should never assent to any proposition, however free from objections it may be, and however clearly and solidly demonstrated.

Hyl: You have satisfied me, Philonous.

Phil: As armament against all future objections, do bear in mind that something bearing equally hard on two contradictory opinions cannot be a proof against either of them. So whenever any difficulty in immaterialism occurs to you, see if you can find a solution for it on the hypothesis of the materialists. Don’t be deceived by words; but test your own thoughts. And if you don’t find it easier with the help of materialism, it obviously can’t be an objection against immaterialism. If you had followed this rule all along, you would probably have spared yourself much trouble in objecting because none of your objections conforms to the rule. I challenge you to show one of your difficulties that is explained by matter; indeed, one that is not made even worse by supposing matter, and consequently counts against materialism rather than for it. In each particular case you should consider whether the difficulty arises from the non-existence of matter. If it doesn’t, then arguing from it to the falsity of immaterialism is arguing from a premise to a conclusion that has nothing to do with it—no better than arguing from ‘Extension is infinitely divisible’ to ‘God does not have foreknowledge’! And yet if you think back I believe you will find this to have been often, if not always, the case in our conversation. Be careful also not to argue by begging the question [that is, giving an argument that at the outset assumes the truth of the conclusion]. One is apt to say: ‘The unknown substances ought to be regarded as real things, rather than the ideas in our minds; and for all we know the unthinking external substance may operate as a cause or instrument in the production of our ideas.’ But doesn’t this assume that there are such external substances? And isn’t this begging the question? But above all things you should beware of misleading yourself by that common fallacy which is called ‘mistaking the question’—that is, offering against one proposition an argument which really counts only against a quite different proposition. You often talked as if you thought I maintained the non-existence of sensible things; whereas in truth no-one can be more thoroughly assured of their existence than I am, and it is you who doubt—no; it is you who positively deny—that they exist. Everything that is seen, felt, heard, or in any way perceived by the senses is a real being according to the principles I embrace, but not according to the principles that used to be yours. Remember that the matter you used to defend is an unknown something (if indeed it can even be called a ‘something’), which is completely stripped of all sensible qualities, and can’t be perceived through the senses or grasped by the mind. Remember, I say, that your matter is not any object that is hard or soft, hot or cold, blue or white, round or square, etc. For I affirm that all these things do exist; though I do indeed deny that they exist in any way except by being perceived, or that they exist out of all minds whatsoever. Think about these points; consider them attentively and keep them in view. Otherwise you won’t be clear about the state of the question; and in that case your objections will always be wide of the mark, and instead of counting against my views they may possibly be directed (as more than once they have been) against yours.

Hyl: I have to admit, Philonous, that nothing seems to have kept me from agreeing with you more than this same mistaking the question that you have just warned me against. When you deny matter I am tempted at first glance to think that you are denying the things we see and feel; but on reflection I find there is no ground for that. How about keeping the word ‘matter’, and applying it to sensible things? This could be done without any change in your views; and believe me it would reconcile your views to some people who are upset more by your use of words than by your opinions.

Phil: With all my heart: retain the word ‘matter’, and apply it to the objects of sense, if you please, but don’t credit them with existing apart from being perceived. I shan’t quarrel with you over a word. ‘Matter’ and ‘material substance’ are terms introduced by philosophers; and as used by them they imply a sort of independence, or an existence distinct from being perceived by a mind. But common people don’t use these terms, or if they do it is to signify the immediate objects of sense. So one would think that so long as the names of all particular things are retained, and also such terms as ‘sensible’, ‘substance’, ‘body’, and ‘stuff’, the word ‘matter’ would never be missed in common talk. And in philosophical discourses it seems best to leave it out altogether, since the use of that general confused term—more perhaps than any other one factor—has favoured and strengthened the depraved tendency of the mind towards atheism.

Hyl: Well now, Philonous, since I am content to give up the notion of an unthinking substance exterior to the mind, I think you should allow me the privilege of using the word ‘matter’ as I please, to signify a collection of sensible qualities existing only in the mind. I freely grant that strictly speaking there is no other substance than spirit. But I have been accustomed to the term ‘matter’ for so long that I don’t know how to get on without it. To say

There is no matter in the world

is still shocking to me. Whereas to say

There is no matter, if by ‘matter’ is meant an unthinking substance existing outside the mind; but if by ‘matter’ is meant some sensible thing whose existence consists in being perceived, then there is matter

comes across quite differently, and this formulation will bring men to your notions with little difficulty. For, after all, the controversy about matter in the strict sense of ‘matter’ is not a dispute between you and ordinary folk. It lies altogether between you and the philosophers, whose principles are admittedly nowhere near so natural or so agreeable to the common sense of mankind and to holy scripture as yours are. All our desires are directed towards gaining happiness or avoiding misery. But what have happiness or misery, joy or grief, pleasure or pain, to do with absolute existence, or with unknown entities, abstracted from all relation to us? It is obvious that things concern us only insofar as they are pleasing or displeasing; and they can please or displease only to the extent that they are perceived. Beyond that, we are not concerned; and in this respect you leave things as you found them. But still there is something new in this doctrine of yours. It is clear to me that I don’t now think with the philosophers, nor do I entirely think with the common people. I would like to know where I stand now—to know precisely what you have added to my former notions or altered in them.

Phil: I don’t claim to be a setter-up of new notions. All I’m trying to do is bring together and place in a clearer light a truth that used to be shared between the common people and the philosophers: the former being of the opinion that the things they immediately perceive are the real things. and the latter that the things they immediately perceive are ideas which exist only in the mind. These two notions, when put together, constitute the substance of what I advance.

Hyl: For a long time I have distrusted my senses: I thought I saw things by a dim light, and through false glasses. Now the glasses are removed, and a new light breaks in on my understanding. I am clearly convinced that I see things as they are, and am no longer troubled about their unknown natures or absolute existence. This is the state I find myself in at present, though indeed I don’t yet fully grasp the line of argument that brought me to it. You set out on the same principles that Academics [= sceptics in ancient Greece], Cartesians, and similar sects usually do; and for a long time it looked as if you were advancing their philosophical scepticism; but in the end your conclusions are directly opposite to theirs.

Phil: Hylas, look at the water of that fountain, how it is forced upwards, in a round column, to a certain height, at which it breaks and falls back into the basin from which it rose. Its ascent, as well as its descent, come from the same uniform law or principle of gravitation. In just that way the same principles which at first view lead to scepticism then, when pursued to a certain point, bring men back to common sense.