§. 21. Ideas being thus diftinguished and understood, we may be able to give an account how the fame water, at the fame time, may produce the idea of cold by one hand, and of heat by the other; whereas it is impoffible that the fame water, if those ideas were really in it, fhould at the fame time be both hot and cold: for if we imagine warmth, as it is in our hands, to be nothing but a certain fort and degree of motion in the minute particles of our nerves, or animal fpirits, we may understand how it is poffible that the fame water may, at the fame time, produce the fenfations of heat in one hand, and cold in the other; which yet figure never does, that never producing the idea of a fquare by one hand, which has produced the idea of a globe by another. But if the fenfation of heat and cold be nothing but the increase or diminution of the motion of the minute parts of our bodies, caufed by the corpufcles of any other body, it is easy to be understood, that if that motion be greater in one hand than in the other; if a body be applied to the two hands, which has in its minute particles a greater motion, than in thofe of one of the hands, and a lefs than in thofe of the other; it will increase the motion of the one hand, and leffen it in the other, and so cause the different fenfations of heat and cold that depend thereon.

§. 22. I have in what just goes before been engaged in phyfical inquiries a little farther than perhaps I intended. But it being neceffary to make the nature of fenfation a little understood, and to make the difference between the qualities in bodies, and the ideas produced by them in the mind, to be diftinctly conceived, without which it were impoffible to difcourfe intelligibly of them; I hope I fhall be pardoned this little excurfion into natural philofophy, it being neceffary in our prefent inquiry to diftinguish the primary and real qualities of bodies, which are always in them (viz. folidity, extenfion, figure, number, and motion, or reft; and are fometimes perceived by us, viz. when the bodies they are in are big enough fingly to be difcerned) from thofe fecondary and imputed qualities, which are but the

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powers

powers of feveral combinations of those primary ones, when they operate, without being diftinctly difcerned; whereby we may also come to know what ideas are, and what are not, refemblances of fomething really exifting in the bodies we denominate from them.

Three forts of qualities in bodies.

§. 23. The qualities then that are in bodies, rightly confidered, are of three forts.

First, the bulk, figure, number, fituation, and motion, or rest of their folid parts; thofe are in them, whether we perceive them or no; and when they are of that fize, that we can discover them, we have by these an idea of the thing, as it is in itself, as is plain in artificial things. Thefe I call primary qualities.

Secondly, the power that is in any body, by reason of its infenfible primary qualities, to operate after a peculiar manner on any of our fenfes, and thereby produce in us the different ideas of feveral colours, founds, fmells, taftes, &c. These are ufually called fenfible qualities.

Thirdly, The power that is in any body, by reason of the particular conftitution of its primary qualities, to make fuch a change in the bulk, figure, texture, and motion of another body, as to make it operate on our fenfes, differently from what it did before. Thus the fun has a power to make wax white, and fire to make lead fluid. These are ufually called powers.

The firft of thefe, as has been faid, I think, may be properly called real, original, or primary qualities, because they are in the things themselves, whether they are perceived or no; and upon their different modifica tions it is, that the fecondary qualities depend.

The other two are only powers to act differently upon other things, which powers refult from the different modifications of thofe primary qualities.

The first are

§. 24. But though the two latter forts refemblances. of qualities are powers barely, and nothing. but powers, relating to feveral other bodies, and refulting from the different modifications of the original qualities; yet they are generally otherwife thought of. For

The fecond thought refemblances, but are not. The third

the

neither are,

nor are

thought fo,

the fecond fort, viz. the powers to produce feveral ideas in us by our fenfes, are looked upon as real qualities, in the things thus affecting us: but the third fort are called and efteemed barely powers, v. g. the idea of heat, or light, which we receive by our eyes or touch from the fun, are commonly thought real qualities, exifting in the fun, and fomething more than mere powers in it. But when we confider the fun, in reference to wax, which it melts or blanches, we look on the whitenefs and foftnefs produced in the wax, not as qualities in the fun, but effects produced by powers in it: whereas, if rightly confidered, thefe qualities of light and warmth, which are perceptions in me when I am warmed, or enlightened by the fun, are no otherwise in the fun, than the changes made in the wax, when it is blanched or melted, are in the fun. They are all of them equally powers in the fun, depending on its primary qualities; whereby it is able, in the one cafe, fo to alter the bulk, figure, texture, or motion of fome of the infenfible parts of my eyes or hands, as thereby to produce in me the idea of light or heat; and in the other, it is able fo to alter the bulk, figure, texture, or motion of the infenfible parts of the wax, as to make them fit to produce in me the diftinct ideas of white and fluid.

§. 25. The reason why the one are ordinarily taken for real qualities, and the other only for bare powers, feems to be, because the ideas we have of distinct colours, founds, &c. containing nothing at all in them of bulk, figure, or motion, we are not apt to think them the effects of thefe primary qualities, which appear not, to our fenfes, to operate in their production; and with which they have not any apparent congruity, or conceivable connexion. Hence it is that we are fo forward to imagine, that thofe ideas are the refemblances of fomething really exifting in the objects themselves; fince fenfation difcovers nothing of bulk, figure, or motion of parts in their production; nor can reafon fhow how bodies, by their bulk, figure, and mo

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tion

tion, fhould produce in the mind the ideas of blue or yellow, &c. But in the other cafe, in the operations of bodies, changing the qualities one of another, we plainly discover, that the quality produced hath commonly no refemblance with any thing in the thing producing it; wherefore we look on it as a bare effect of power. For though receiving the idea of heat, or light, from the fun, we are apt to think it is a perception and refemblance of fuch a quality in the fun; yet when we fee wax, or a fair face, receive change of colour from the fun, we cannot imagine that to be the reception or refemblance of any thing in the fun, because we find not thofe different colours in the fun itself. For our fenfes being able to obferve a likeness or unlikeness of fenfible qualities in two different external objects, we forwardly enough conclude the production of any fenfible quality in any fubject to be an effect of bare power, and not the communication of any quality, which was really in the efficient, when we find no fuch fenfible quality in the thing that produced it. But our fenfes not being able to discover any unlikeness between the idea produced in us, and the quality of the object producing it; we are apt to imagine, that our ideas are refemblances of fomething in the objects, and not the effects of certain powers placed in the modification of their primary qualities; with which primary qualities the ideas produced in us have no refemblance.

Secondary qualities two fold; firft, immediately perceivable; fecondly, mediately per

§. 26. To conclude, befide those beforementioned primary qualities in bodies, viz. bulk, figure, extenfion, number, and motion of their folid parts; all the reft whereby we take notice of bodies, and distinguish them one from another, are nothing elfe ceivable. but feveral powers in them depending on thofe primary qualities; whereby they are fitted, either by immediately operating on our bodies, to produce feveral different ideas in us; or elfe by operating on other bodies, fo to change their primary qualities, as to render them capable of producing ideas in us, different

ferent from what before they did. The former of these, I think, may be called fecondary qualities, immediately perceivable: the latter, fecondary qualities, mediately perceivable.

§. I.

CHAP. IX.

Of Perception.

Perception the firft fimple idea of reflection.

ERCEPTION, as it is the firft faculty of the mind, exercised about our ideas; fo it is the first and fimpleft idea we have from reflection, and is by fome called thinking in general. Though thinking, in, the propriety of the English tongue, fignifies that fort of operation in the mind about its ideas, wherein the mind is active; where it, with fome degree of voluntary attention, confiders any thing. For in bare naked perception, the mind is, for the most part, only paffive; and what it perceives, it cannot avoid perceiving.

§. 2. What perception is, every one will Is only when know better by reflecting on what he does the mind rehimself, what he fees, hears, feels, &c. or ceives the thinks, than by any difcourfe of mine. impreffion. Whoever reflects on what paffes in his own mind, cannot miss it: and if he does not reflect, all the words in the world cannot make him have any notion of it.

§. 3. This is certain, that whatever alterations are made in the body, if they reach not the mind; whatever impreffions are made on the outward parts, if they are not taken notice of within; there is no perception. Fire may burn our bodies, with no other effect, than it does a billet, unless the motion be continued to the brain, and there the sense of heat, or idea of pain, be produced in the mind, wherein confifts actual perception. §. 4. How