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Some further Considerations concerning our Simple
S 1. CONCERNING the simple ideas of P sensation it is to be considered, that what- ideas from soever is so constituted in nature as to privative be able, by affecting our senses, to cause causes. any perception in the mind, doth thereby produce in the understanding a simple idea, which, whatever be the external cause of it, when it comes to be taken notice of by our discerning faculty, it is by the mind looked on and considered there to be a real positive idea in the understanding, as much as any other whatsoever, though perhaps the cause of it be but ad.. privation of the subject.
S 2. Thus the idea of heat and cold, light and darkness, white and black, motion and rest, are equally clear and positive ideas in the mind, though perhaps some of the causes which produce them are barely privations in subjects, from whence our senses derive those ideas. These the understanding, in its view of them, considers all as distinct positive ideas, without taking notice of the causes that produce them; which is an inquiry not belonging to the idea, as it is in the understanding, but to the nature of the things existing without us. These are two very different things, and carefully to be distinguished; it being one thing to perceive and know the idea of white or black, and quite another to examine what kind of particles they must be, and how ranged in the superficies, to make any object appear white or black.
S 3. A painter or dyer, who never inquired into their causes, hath the ideas of white and black, and other colours, as clearly, perfectly, and distinctly in
his understanding, and perhaps more distinctly, than the philosopher, who hath busied himself in considering their natures, and thinks he knows how far either of them is in its cause positive or privative; and the idea of black is no less positive in his mind than that of white, however the cause of that colour in the external object may be only a privation.
S 4. If it were the design of my present undertaking to inquire into the natural causes and manner of perception, I should offer this as a reason why a privative cause might, in some cases at least, produce a positive idea, viz. that all sensation being produced in us only by different degrees and modes of motion in our animal spirits, variously agitated by external objects, the abatement of any former motion must as necessarily produce a new sensation, as the variation or increase of it; and so introduce a new idea, which depends only on a different motion of the animal spirits in that organ.
S 5. But whether this be so or no, I will not here determine, but appeal to every one's own experience, whether the shadow of a man, though it consists of nothing but the absence of light (and the more the absence of light is, the more discernible is the shadow) does not, when a man looks on it, cause as clear and positive idea in his mind, as a man himself, though covered over with clear sunshine ? and the picture of a shadow is a positive thing. Indeed, we have negative names, which stand not directly for positive ideas, but for their absence, such as insipid, silence, nihil, &c. which words denote positive ideas; v.g. taste, sound, being, with a signification of their absence. Positive
S 6. And thus one may truly be said to ideas from see darkness. For supposing a hole per
fectly dark, from whence no light is recauses. flected, it is certain one may see the figure of it, or it may be painted; or whether the ink I write with makes any other idea, is a question. The privative causes I have here assigned of positive ideas are according to the common opinion; but in truth it will be hard to determine whether there be really any ideas from a privative cause, till it be determined whether rest be any more a privation than motion.
$ 7. To discover the nature of our ideas the better, and to discourse of them in mind, qualitelligibly, it will be convenient to di- ties in bostinguish them as they are ideas or per- dies. ceptions in our minds, and as they are modifications of matter in the bodies that cause such perceptions in us; that so we may not think (as perhaps usually is done) that they are exactly the images and resenblances of something inherent in the subject; most of those of sensation being in the mind no more the likeness of something existing without us, than the names that stand for them are the likeness of our ideas, which yet upon hearing they are apt to excite in us.
S 8. Whatsoever the mind perceives in itself, or is the immediate object of perception, thought, or understanding, that I call idea; and the power to produce any idea in our mind I call quality of the subject wherein that power is. Thus a snow-ball having the power to produce in us the ideas of white, cold, and round, the powers to produce those ideas in us, as they are in the snow-ball, I call qualities; and as they are sensations or perceptions in our understandings, I call them ideas; which ideas, if I speak of sometimes as in the things themselves, I would be understood to mean those qualities in the objects which produce them in us.
S 9. Qualities thus considered in bodies are, first, such as are utterly inseparable from the body, in what estate soever it be;
que such as in all the alterations and changes it suffers, all the force can be used upon it, it constantly keeps; and such as sense constantly finds in every particle of matter which has bulk enough to be perceived, and the mind finds inseparable from every particle of matter, though less than to make itself singly be perceived by our senses; v. g. take a grain of wheat, divide it into two parts, each part has still solidity, extension, figure, and mobility ; divide it again, and it retains still the same qualities, and so divide it on till the parts become insensible, they must retain still each of them all those qualities : for division (which is all that a mill, or pestle, or any other body does upon another, in reducing it to insensible parts) can never take away either solidity, extension, figure, or mobility from any body, but only makes two or more distinct separate masses of matter of that which was but one before; all which distinct masses, reckoned as so many distinct bodies, after division make a certain number. These I call original or primary qualities of body, which I think we may observe to produce simple ideas in us, viz. solidity, extension, figure, motion or rest, and number.
S 10. Secondly, such qualities which Secondary in truth are nothing in the objects themqualities.
selves, but powers to produce various sensations in us by their primary qualities, i.e. by the bulk, figure, texture, and motion of their insensible parts, as colour, sounds, tastes, &c. these I call secondary qualities. To these might be added a third sort, which are allowed to be barely powers, though they are as much real qualities in the subject as those which I, to comply with the common way of speaking, call qualities, but for distinction, secondary qualities. For the power in fire to produce a new colour, or consistency, in wax or clay, by its primary qualities, is as much a quality in fire as the power it has to produce in me a new idea or sensation of warmth or burning, which I felt not before, by the same primary qualities, viz. the bulk, texture, and motion of its insensible parts.
$ 11. The next thing to be considered is, how bodies produce ideas in us; and that is mary qualimanifestly by impulse, the only way which ties produce we can conceive bodies to operate in their ideas.
$ 12. If then external objects be not united to our minds, when they produce ideas therein, and yet we perceive these original qualities in such of them as singly fall under our senses, it is evident that some motion must be thence continued by our nerves or animal spirits, by some parts of our bodies, to the brain, or the seat of sensation, there to produce in our minds the particular ideas we have of them. And since the extension, figure, number, and motion of bodies, of an observable bigness, may be perceived at a distance by the sight, it is evident some singly imperceptible bodies must come from them to the eyes, and thereby convey to the brain some motion, which produces these ideas which we have of them in us. § 13. After the same manner that the
How seconideas of these original qualities are produced in us, we may conceive that the ideas of secondary qualities are also produced, viz. by the operations of insensible particles on our senses. For it being manifest that there are bodies, and good store of bodies, each whereof are so small that we cannot, by any of our senses, discover either their bulk, figure, or motion, as is evident in the particles of the air and water, and others extremely smaller than those, perhaps as much smaller than the particles of air and water as the particles of air and water are smaller than peas or hail-stones : let us suppose at present that the different motions and figures, bulk and number of such particles, affecting the several organs of our senses, produce in us those different sensations, which we have from the colours and smells of bodies; v. g. that a violet, by the impulse of such insensible particles of matter of peculiar figures and bulks, and in different degrees and modifications of their motions, causes the ideas of the blue colour and