Dialogue IPHIL. This point then is agreed between us--That SENSIBLE THINGS ARE THOSE ONLY WHICH ARE IMMEDIATELY PERCEIVED BY SENSE. You will farther inform me, whether we immediately perceive by sight anything beside light, and colours, and figures; or by hearing, anything but sounds; by the palate, anything beside tastes; by the smell, beside odours; or by the touch, more than tangible qualities.

HYL. We do not.

PHIL. It seems, therefore, that if you take away all sensible qualities, there remains nothing sensible?

HYL. I grant it.

PHIL. Sensible things therefore are nothing else but so many sensible qualities, or combinations of sensible qualities?

HYL. Nothing else.

PHIL. HEAT then is a sensible thing?

HYL. Certainly.

PHIL. Doth the REALITY of sensible things consist in being perceived? or, is it something distinct from their being perceived, and that bears no relation to the mind?

HYL. To EXIST is one thing, and to be PERCEIVED is another.

PHIL. I speak with regard to sensible things only. And of these I ask, whether by their real existence you mean a subsistence exterior to the mind, and distinct from their being perceived?

HYL. I mean a real absolute being, distinct from, and without any relation to, their being perceived.

PHIL. Heat therefore, if it be allowed a real being, must exist without the mind?

HYL. It must.

PHIL. Tell me, Hylas, is this real existence equally compatible to all degrees of heat, which we perceive; or is there any reason why we should attribute it to some, and deny it to others? And if there be, pray let me know that reason.

HYL. Whatever degree of heat we perceive by sense, we may be sure the same exists in the object that occasions it.

PHIL. What! the greatest as well as the least?

HYL. I tell you, the reason is plainly the same in respect of both. They are both perceived by sense; nay, the greater degree of heat is more sensibly perceived; and consequently, if there is any difference, we are more certain of its real existence than we can be of the reality of a lesser degree.

PHIL. But is not the most vehement and intense degree of heat a very great pain?

HYL. No one can deny it.

PHIL. And is any unperceiving thing capable of pain or pleasure?

HYL. No, certainly.

PHIL. Is your material substance a senseless being, or a being endowed with sense and perception?

HYL. It is senseless without doubt.

PHIL. It cannot therefore be the subject of pain?

HYL. By no means.

PHIL. Nor consequently of the greatest heat perceived by sense, since you acknowledge this to be no small pain?

HYL. I grant it.

PHIL. What shall we say then of your external object; is it a material Substance, or no?

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

PHIL. How then can a great heat exist in it, since you own it cannot in a material substance? I desire you would clear this point.

HYL. Hold, Philonous, I fear I was out in yielding intense heat to be a pain. It should seem rather, that pain is something distinct from heat, and the consequence or effect of it.

PHIL. Upon putting your hand near the fire, do you perceive one simple uniform sensation, or two distinct sensations?

HYL. But one simple sensation.

PHIL. Is not the heat immediately perceived?

HYL. It is.

PHIL. And the pain?

HYL. True.

PHIL. Seeing therefore they are both immediately perceived at the same time, and the fire affects you only with one simple or uncompounded idea, it follows that this same simple idea is both the intense heat immediately perceived, and the pain; and, consequently, that the intense heat immediately perceived is nothing distinct from a particular sort of pain.

HYL. It seems so.

PHIL. Again, try in your thoughts, Hylas, if you can conceive a vehement sensation to be without pain or pleasure.

HYL. I cannot.

PHIL. Or can you frame to yourself an idea of sensible pain or pleasure in general, abstracted from every particular idea of heat, cold, tastes, smells? &c.

HYL. I do not find that I can.

PHIL. Doth it not therefore follow, that sensible pain is nothing distinct from those sensations or ideas, in an intense degree?

HYL. It is undeniable; and, to speak the truth, I begin to suspect a very great heat cannot exist but in a mind perceiving it.

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

HYL. I think I may be positive in the point. A very violent and painful heat cannot exist without the mind.

PHIL. It hath not therefore according to you, any REAL being?

HYL. I own it.

PHIL. Is it therefore certain, that there is no body in nature really hot?

HYL. I have not denied there is any real heat in bodies. I only say, there is no such thing as an intense real heat.

PHIL. But, did you not say before that all degrees of heat were equally real; or, if there was any difference, that the greater were more undoubtedly real than the lesser?

HYL. True: but it was because I did not then consider the ground there is for distinguishing between them, which I now plainly see. And it is this: because intense heat is nothing else but a particular kind of painful sensation; and pain cannot exist but in a perceiving being; it follows that no intense heat can really exist in an unperceiving corporeal substance. But this is no reason why we should deny heat in an inferior degree to exist in such a substance.

PHIL. But how shall we be able to discern those degrees of heat which exist only in the mind from those which exist without it?

HYL. That is no difficult matter. You know the least pain cannot exist unperceived; whatever, therefore, degree of heat is a pain exists only in the mind. But, as for all other degrees of heat, nothing obliges us to think the same of them.

PHIL. I think you granted before that no unperceiving being was capable of pleasure, any more than of pain.

HYL. I did.

PHIL. And is not warmth, or a more gentle degree of heat than what causes uneasiness, a pleasure?

HYL. What then?

PHIL. Consequently, it cannot exist without the mind in an unperceiving substance, or body.

HYL. So it seems.

PHIL. Since, therefore, as well those degrees of heat that are not painful, as those that are, can exist only in a thinking substance; may we not conclude that external bodies are absolutely incapable of any degree of heat whatsoever?

HYL. On second thoughts, I do not think it so evident that warmth is a pleasure as that a great degree of heat is a pain.

PHIL. I do not pretend that warmth is as great a pleasure as heat is a pain. But, if you grant it to be even a small pleasure, it serves to make good my conclusion.

HYL. I could rather call it an INDOLENCE. It seems to be nothing more than a privation of both pain and pleasure. And that such a quality or state as this may agree to an unthinking substance, I hope you will not deny.

PHIL. If you are resolved to maintain that warmth, or a gentle degree of heat, is no pleasure, I know not how to convince you otherwise than by appealing to your own sense. But what think you of cold?

HYL. The same that I do of heat. An intense degree of cold is a pain; for to feel a very great cold, is to perceive a great uneasiness: it cannot therefore exist without the mind; but a lesser degree of cold may, as well as a lesser degree of heat.

PHIL. Those bodies, therefore, upon whose application to our own, we perceive a moderate degree of heat, must be concluded to have a moderate degree of heat or warmth in them; and those, upon whose application we feel a like degree of cold, must be thought to have cold in them.

HYL. They must.

PHIL. Can any doctrine be true that necessarily leads a man into an absurdity?

HYL. Without doubt it cannot.

PHIL. Is it not an absurdity to think that the same thing should be at the same time both cold and warm?

HYL. It is.

PHIL. Suppose now one of your hands hot, and the other cold, and that they are both at once put into the same vessel of water, in an intermediate state; will not the water seem cold to one hand, and warm to the other?

HYL. It will.

PHIL. Ought we not therefore, by your principles, to conclude it is really both cold and warm at the same time, that is, according to your own concession, to believe an absurdity?

HYL. I confess it seems so.

PHIL. Consequently, the principles themselves are false, since you have granted that no true principle leads to an absurdity.