Part 36

_Phil._ I say it is nothing to the purpose. Our discourse proceeded altogether concerning sensible things, which you defined to be, _the things we immediately perceive by our senses_. Whatever other qualities, therefore, you speak of, as distinct from these, I know nothing of them, neither do they at all belong to the point in dispute. You may, indeed, pretend to have discovered certain qualities which you do not perceive, and assert those insensible qualities exist in fire and sugar. But what use can be made of this to your present purpose, I am at a loss to conceive. Tell me then once more, do you acknowledge that heat and cold, sweetness and bitterness (meaning those qualities which are perceived by the senses), do not exist without the mind?

_Hyl._ I see it is to no purpose to hold out, so I give up the cause as to those mentioned qualities. Though I profess it sounds oddly, to say that sugar is not sweet.

_Phil._ But, for your farther satisfaction, take this along with you: that which at other times seems sweet, shall, to a distempered palate, appear bitter. And, nothing can be plainer than that divers persons perceive different tastes in the same food; since that which one man delights in, another abhors. And how could this be, if the taste was something really inherent in the food?

_Hyl._ I acknowledge I know not how.

_Phil._ In the next place, _odours_ are to be considered. And, with regard to these, I would fain know whether what hath been said of tastes doth not exactly agree to them? Are they not so many pleasing or displeasing sensations?

_Hyl._ They are.

_Phil._ Can you then conceive it possible that they should exist in an unperceiving thing?

_Hyl._ I cannot.

_Phil._ Or, can you imagine that filth and ordure affect those brute animals that feed on them out of choice, with the same smells which we perceive in them?

_Hyl._ By no means.

_Phil._ May we not therefore conclude of smells, as of the other forementioned qualities, that they cannot exist in any but a perceiving substance or mind?

_Hyl._ I think so.

_Phil._ Then as to _sounds_, what must we think of them: are they accidents really inherent in external bodies, or not?

_Hyl._ That they inhere not in the sonorous bodies is plain from hence: because a bell struck in the exhausted receiver of an air-pump sends forth no sound. The air, therefore, must be thought the subject of sound.

_Phil._ What reason is there for that, Hylas?

_Hyl._ Because, when any motion is raised in the air, we perceive a sound greater or lesser, according to the air’s motion; but without some motion in the air, we never hear any sound at all.

_Phil._ And granting that we never hear a sound but when some motion is produced in the air, yet I do not see how you can infer from thence, that the sound itself is in the air.

_Hyl._ It is this very motion in the external air that produces in the mind the sensation of _sound_. For, striking on the drum of the ear, it causeth a vibration, which by the auditory nerves being communicated to the brain, the soul is thereupon affected with the sensation called _sound_.

_Phil._ What! is sound then a sensation?

_Hyl._ I tell you, as perceived by us, it is a particular sensation in the mind.

_Phil._ And can any sensation exist without the mind?

_Hyl._ No, certainly.

_Phil._ How then can sound, being a sensation, exist in the air, if by the _air_ you mean a senseless substance existing without the mind?

_Hyl._ You must distinguish, Philonous, between sound as it is perceived by us, and as it is in itself; or (which is the same thing) between the sound we immediately perceive, and that which exists without us. The former, indeed, is a particular kind of sensation, but the latter is merely a vibrative or undulatory motion in the air.

_Phil._ I thought I had already obviated that distinction, by the answer I gave when you were applying it in a like case before. But, to say no more of that, are you sure then that sound is really nothing but motion?

_Hyl._ I am.

_Phil._ Whatever therefore agrees to real sound, may with truth be attributed to motion?

_Hyl._ It may.

_Phil._ It is then good sense to speak of _motion_ as of a thing that is _loud, sweet, acute, or grave_.

_Hyl._ I see you are resolved not to understand me. Is it not evident those accidents or modes belong only to sensible sound, or _sound_ in the common acceptation of the word, but not to _sound_ in the real and philosophic sense; which, as I just now told you, is nothing but a certain motion of the air?

_Phil._ It seems then there are two sorts of sound—the one vulgar, or that which is heard, the other philosophical and real?

_Hyl._ Even so.

_Phil._ And the latter consists in motion?

_Hyl._ I told you so before.

_Phil._ Tell me, Hylas, to which of the senses, think you, the idea of motion belongs? to the hearing?

_Hyl._ No, certainly; but to the sight and touch.

_Phil._ It should follow then, that, according to you, real sounds may possibly be _seen_ or _felt_, but never _heard_.

_Hyl._ Look you, Philonous, you may, if you please, make a jest of my opinion, but that will not alter the truth of things. I own, indeed, the inferences you draw me into sound something oddly; but common language, you know, is framed by, and for the use of the vulgar: we must not therefore wonder if expressions adapted to exact philosophic notions seem uncouth and out of the way.

_Phil._ Is it come to that? I assure you, I imagine myself to have gained no small point, since you make so light of departing from common phrases and opinions; it being a main part of our inquiry, to examine whose notions are widest of the common road, and most repugnant to the general sense of the world. But, can you think it no more than a philosophical paradox, to say that _real sounds are never heard_, and that the idea of them is obtained by some other sense? And is there nothing in this contrary to nature and the truth of things?

_Hyl._ To deal ingenuously, I do not like it. And, after the concessions already made, I had as well grant that sounds too have no real being without the mind.

_Phil._ And I hope you will make no difficulty to acknowledge the same of _colours_.

_Hyl._ Pardon me: the case of colours is very different. Can anything be plainer than that we see them on the objects?

_Phil._ The objects you speak of are, I suppose, corporeal Substances existing without the mind?

_Hyl._ They are.

_Phil._ And have true and real colours inhering in them?

_Hyl._ Each visible object hath that colour which we see in it.

_Phil._ How! is there anything visible but what we perceive by sight?

_Hyl._ There is not.

_Phil._ And, do we perceive anything by sense which we do not perceive immediately?

_Hyl._ How often must I be obliged to repeat the same thing? I tell you, we do not.

_Phil._ Have patience, good Hylas; and tell me once more, whether there is anything immediately perceived by the senses, except sensible qualities. I know you asserted there was not; but I would now be informed, whether you still persist in the same opinion.

_Hyl._ I do.

_Phil._ Pray, is your corporeal substance either a sensible quality, or made up of sensible qualities?

_Hyl._ What a question that is! who ever thought it was?

_Phil._ My reason for asking was, because in saying, _each visible object hath that colour which we see in it_, you make visible objects to be corporeal substances; which implies either that corporeal substances are sensible qualities, or else that there is something beside sensible qualities perceived by sight: but, as this point was formerly agreed between us, and is still maintained by you, it is a clear consequence, that your _corporeal substance_ is nothing distinct from _sensible qualities_(794).

_Hyl._ You may draw as many absurd consequences as you please, and endeavour to perplex the plainest things; but you shall 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 are unwilling to have your notion of corporeal substance examined, I shall urge that point no farther. Only be pleased to let me know, whether the same colours which we see exist in external bodies, or some other.

_Hyl._ The very same.

_Phil._ What! are then the beautiful red and purple we see on yonder clouds really in them? Or do you imagine they have in themselves any other form than that of a dark mist or vapour?

_Hyl._ I must own, Philonous, those colours are not really in the clouds as they seem to be at this distance. They are only apparent colours.

_Phil._ _Apparent_ call you them? how shall we distinguish these apparent colours from real?

_Hyl._ Very easily. Those are to be thought apparent which, appearing only at a distance, vanish upon a nearer approach.

_Phil._ And those, I suppose, are to be thought real which are discovered by the most near and exact survey.

_Hyl._ Right.

_Phil._ Is the nearest and exactest survey made by the help of a microscope, or by the naked eye?

_Hyl._ By a microscope, doubtless.

_Phil._ But a microscope often discovers colours in an object different from those perceived by the unassisted sight. And, in case we had microscopes magnifying to any assigned degree, it is certain that no object whatsoever, viewed through them, would appear in the same colour which it exhibits to the naked eye.

_Hyl._ And what will you conclude from all this? You cannot argue that there are really and naturally no colours on objects: because by artificial managements they may be altered, or made to vanish.

_Phil._ I think it may evidently be concluded from your own concessions, that all the colours we see with our naked eyes are only apparent as those on the clouds, since they vanish upon a more close and accurate inspection which is afforded us by a microscope. Then, as to what you say by way of prevention: I ask you whether the real and natural state of an object is better discovered by a very sharp and piercing sight, or by one which is less sharp?

_Hyl._ By the former without doubt.

_Phil._ Is it not plain from _Dioptrics_ that microscopes make the sight more penetrating, and represent objects as they would appear to the eye in case it were naturally endowed with a most exquisite sharpness?

_Hyl._ It is.

_Phil._ Consequently the microscopical representation is to be thought that which best sets forth the real nature of the thing, or what it is in itself. The colours, therefore, by it perceived are more genuine and real than those perceived otherwise.

_Hyl._ I confess there is something in what you say.

_Phil._ Besides, it is not only possible but manifest, that there actually are animals whose eyes are by nature framed to perceive those things which by reason of their minuteness escape our sight. What think you of those inconceivably small animals perceived by glasses? Must we suppose they are all stark blind? Or, in case they see, can it be imagined their sight hath not the same use in preserving their bodies from injuries, which appears in that of all other animals? And if it hath, is it not evident they must see particles less than their own bodies; which will present them with a far different view in each object from that which strikes our senses(795)? Even our own eyes do not always represent objects to us after the same manner. In the jaundice every one knows that all things seem yellow. Is it not therefore highly probable those animals in whose eyes we discern a very different texture from that of ours, and whose bodies abound with different humours, do not see the same colours in every object that we do? From all which, should it not seem to follow that all colours are equally apparent, and that none of those which we perceive are really inherent in any outward object?

_Hyl._ It should.

_Phil._ The point will be past all doubt, if you consider that, in case colours were real properties or affections inherent in external bodies, they could admit of no alteration without some change wrought in the very bodies themselves: but, is it not evident from what hath been said that, upon the use of microscopes, upon a change happening in the humours of the eye, or a variation of distance, without any manner of real alteration in the thing itself, the colours of any object are either changed, or totally disappear? Nay, all other circumstances remaining the same, change but the situation of some objects, and they shall present different colours to the eye. The same thing happens upon viewing an object in various degrees of light. And what is more known than that the same bodies appear differently coloured by candle-light from what they do in the open day? Add to these the experiment of a prism which, separating the heterogeneous rays of light, alters the colour of any object, and will cause the whitest to appear of a deep blue or red to the naked eye. And now tell me whether you are still of opinion that every body hath its true real colour inhering in it; and, if you think it hath, I would fain know farther from you, what certain distance and position of the object, what peculiar texture and formation of the eye, what degree or kind of light is necessary for ascertaining that true colour, and distinguishing it from apparent ones.

_Hyl._ I own myself entirely satisfied, that they are all equally apparent, and that there is no such thing as colour really inhering in external bodies, but that it is altogether in the light. And what confirms me in this opinion is, that in proportion to the light colours are still more or less vivid; and if there be no light, then are there no colours perceived. Besides, allowing there are colours on external objects, yet, how is it possible for us to perceive them? For no external body affects the mind, unless it acts first on our organs of sense. But the only action of bodies is motion; and motion cannot be communicated otherwise than by impulse. A distant object therefore cannot act on the eye; nor consequently make itself or its properties perceivable to the soul. Whence it plainly follows that it is immediately some contiguous substance, which, operating on the eye, occasions a perception of colours: and such is light.

_Phil._ How! is light then a substance?

_Hyl._ I tell you, Philonous, external light is nothing but a thin fluid substance, whose minute particles being agitated with a brisk motion, and in various manners reflected from the different surfaces of outward objects to the eyes, communicate different motions to the optic nerves; which, being propagated to the brain, cause therein various impressions; and these are attended with the sensations of red, blue, yellow, &c.

_Phil._ It seems then the light doth no more than shake the optic nerves.

_Hyl._ Nothing else.

_Phil._ And consequent to 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 without the mind.

_Hyl._ They have not.

_Phil._ How then do you affirm that colours are in the light; since by _light_ you understand a corporeal substance external to the mind?

_Hyl._ Light and colours, as immediately perceived by us, I grant cannot exist without the mind. But in themselves they are only the motions and configurations of certain insensible particles of matter.

_Phil._ Colours then, in the vulgar sense, or taken for the immediate objects of sight, cannot agree to any but a perceiving substance.

_Hyl._ That is what I say.

_Phil._ Well then, since you give up the point as to those sensible qualities which are alone thought colours by all mankind beside, you may hold what you please with regard to those invisible ones of the philosophers. It is not my business to dispute about _them_; only I would advise you to bethink yourself, whether, considering the inquiry we are upon, it be prudent for you to affirm—_the red and blue which we see are not real colours, but certain unknown motions and figures which no man ever did or can see are truly so_. Are not these shocking notions, and are not they subject to as many ridiculous inferences, as those you were obliged to renounce before in the case of sounds?

_Hyl._ I frankly own, Philonous, that it is in vain to stand out any longer. Colours, sounds, tastes, in a word all those termed _secondary qualities_, have certainly no existence without the mind. But by this acknowledgment I must not be supposed to derogate anything from the reality of Matter, or external objects; seeing it is no more than several philosophers maintain(796), who nevertheless are the farthest imaginable from denying Matter. For the clearer understanding of this, you must know sensible qualities are by philosophers divided into _Primary_ and _Secondary_(797). The former are Extension, Figure, Solidity, Gravity, Motion, and Rest; and these they hold exist really in Bodies. The latter are those above enumerated; or, briefly, _all sensible qualities beside the Primary_; which they assert are only so many sensations or ideas existing nowhere but in the mind. But all this, I doubt not, you are apprised of. For my part, I have been a long time sensible there was such an opinion current among philosophers, but was never thoroughly convinced of its truth until now.

_Phil._ You are still then of opinion that _extension_ and _figures_ are inherent in external unthinking substances?

_Hyl._ I am.

_Phil._ But what if the same arguments which are brought against Secondary Qualities will hold good against these also?

_Hyl._ Why then I shall be obliged to think, they too exist only in the mind.

_Phil._ Is it your opinion the very figure and extension which you perceive by sense exist in the outward object or material substance?

_Hyl._ It is.

_Phil._ Have all other animals as good grounds to think the same of the figure and extension which they see and feel?

_Hyl._ Without doubt, if they have any thought at all.

_Phil._ Answer me, Hylas. Think you the senses were bestowed upon all animals for their preservation and well-being in life? or were they given to men alone for this end?

_Hyl._ I make no question but they have the same use in all other animals.

_Phil._ If so, is it not necessary they should be enabled by them to perceive their own limbs, and those bodies which are capable of harming them?

_Hyl._ Certainly.

_Phil._ A mite therefore must be supposed to see his own foot, and things equal or even less than it, as bodies of some considerable dimension; though at the same time they appear to you scarce discernible, or at best as so many visible points(798)?

_Hyl._ I cannot deny it.

_Phil._ And to creatures less than the mite they will seem yet larger?

_Hyl._ They will.

_Phil._ Insomuch that what you can hardly discern will to another extremely minute animal appear as some huge mountain?

_Hyl._ All this I grant.

_Phil._ Can one and the same thing be at the same time in itself of different dimensions?

_Hyl._ That were absurd to imagine.

_Phil._ But, from what you have laid down it follows that both the extension by you perceived, and that perceived by the mite itself, as likewise all those perceived by lesser animals, are each of them the true extension of the mite’s foot; that is to say, by your own principles you are led into an absurdity.

_Hyl._ There seems to be some difficulty in the point.

_Phil._ Again, have you not acknowledged that no real inherent property of any object can be changed without some change in the thing itself?

_Hyl._ I have.

_Phil._ But, as we approach to or recede from an object, the visible extension varies, being at one distance ten or a hundred times greater than at another. Doth it not therefore follow from hence likewise that it is not really inherent in the object?

_Hyl._ I own I am at a loss what to think.

_Phil._ Your judgment will soon be determined, if you will venture to think as freely concerning this quality as you have done concerning the rest. Was it not admitted as a good argument, that neither heat nor cold was in the water, because it seemed warm to one hand and cold to the other?

_Hyl._ It was.

_Phil._ Is it not the very same reasoning to conclude, there is no extension or figure in an object, because to one eye it shall seem little, smooth, and round, when at the same time it appears to the other, great, uneven, and angular?

_Hyl._ The very same. But does this latter fact ever happen?

_Phil._ You may at any time make the experiment, by looking with one eye bare, and with the other through a microscope.

_Hyl._ I know not how to maintain it; and yet I am loath to give up _extension_, I see so many odd consequences following upon such a concession.

_Phil._ Odd, say you? After the concessions already made, I hope you will stick at nothing for its oddness. [(799) But, on the other hand, should it not seem very odd, if the general reasoning which includes all other sensible qualities did not also include extension? If it be allowed that no idea, nor anything like an idea, can exist in an unperceiving substance, then surely it follows that no figure, or mode of extension, which we can either perceive, or imagine, or have any idea of, can be really inherent in Matter; 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. Be the sensible quality what it will—figure, or sound, or colour, it seems alike impossible it should subsist in that which doth not perceive it.]

_Hyl._ I give up the point for the present, reserving still a right to retract my opinion, in case I shall hereafter discover any false step in my progress to it.

_Phil._ That is a right you cannot be denied. Figures and extension being despatched, 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._ Is not the motion of a body swift in a reciprocal proportion to the time it takes up in describing any given space? Thus a body that describes a mile in an hour moves three times faster than it would in case it described only a mile in three hours.

_Hyl._ I agree with you.

_Phil._ And is not time measured by the succession of ideas in our minds?

_Hyl._ It is.

_Phil._ And is it not possible ideas should succeed one another twice as fast in your mind as they do in mine, or in that of some spirit of another kind?

_Hyl._ I own it.

_Phil._ Consequently the same body may to another seem to perform its motion over any space in half the time that it doth to you. And the same reasoning will hold as to any other proportion: that is to say, according to your principles (since the motions perceived are both really in the object) it is possible one and the same body shall be really moved the same way at once, both very swift and very slow. How is this consistent either with common sense, or with what you just now granted?

_Hyl._ I have nothing to say to it.

_Phil._ Then as for _solidity_; either you do not mean any sensible quality by that word, and so it is beside our inquiry: or if you do, it must be either hardness or resistance. But both the one and the other are plainly relative to our senses: it being evident that what seems hard to one animal may appear soft to another, who hath greater force and firmness of limbs. Nor is it less plain that the resistance I feel is not in the body.

_Hyl._ I own the very _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 are not things immediately perceived, and therefore are not sensible. This point I thought had been already determined.

_Hyl._ I own it was; but you will pardon me if I seem a little embarrassed: I know not how to quit my old notions.