6

as, insipid,' silence,' nihil,' &c. which words denote the absence of the positive ideas of taste, sound, being, &c. But it will be hard to determine whether we have any positive ideas from a privative cause, till it be determined whether rest be any more a privation than motion. To discover the nature of our ideas, it will be convenient to distinguish them as they are perceptions in our minds, and as they are modifications of matter, causing perceptions in us, that we may not think that they are the exact resemblances of something inherent in the subject. Whatsoever the mind perceives in itself, I call an idea; the power to produce the idea, I call a quality of the subject wherein that power is. Thus a snow-ball producing the ideas of cold, white, round, its powers to produce those ideas I call qualities; and as they are perceptions in the mind, I call them ideas.

Qualities in bodies are first such as are inseparable from the body in what state soever it be. Take a grain of wheat, divide it into two parts, each part has still solidity, extension, figure, and mobility: divide it again and again, till the parts become insensible, they still retain those qualities; for division can never take them away from any body. These, therefore, I call primary qualities.

Such qualities which are but powers to produce various sensations in us by the primary qualities; that is, by the bulk, figure, texture, and motion of their insensible parts, as colors, sounds, tastes, &c. 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, for distinction, call secondary qualities: for the power of fire to produce a new color and consistency in wax by its primary qualities, is as much a quality, as the power it has to produce in me a new idea of warmth or burning, which I felt not before, by the same primary qualities, viz. the bulk, texture, and motion of its insensible parts.

Bodies produce ideas in us by impulse: for if external objects be not united to our minds when they produce ideas there, some motion must be thence continued by our nerves to the seat of sensation, there to produce ideas; and since objects 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 the ideas which we have of them.

In the same manner ideas of secondary qualities are produced. For as it is manifest that there are bodies. so small that our senses cannot discover their bulk, figure, or motion, it is conceivable that the different motions, figure, and bulk of such particles may affect our senses so as to produce the sensations which we have from colors and smells; it being no more impossible to conceive that the ideas of a blue color and a sweet smell in a violet should be annexed to certain motions of insensible particles of matter with which they have no similitude, than that the idea of pain should be annexed to the motion of a piece of steel dividing our flesh, with which that idea has no resemblance. The same may be said of tastes and sounds, and other sensible qualities, which are but powers in the objects to produce sensations in us.

Whence we draw the observation that the ideas of primary qualities are resemblances of them, but secondary qualities are only a power in bodies to produce those sensations in us. Thus flame is denominated hot and light, snow, white and cold, from the ideas they produce in us. If the same fire at a distance produces warmth, and at a nearer approach causes pain, why should we imagine that the idea of warmth is in the fire, and the idea of pain, produced by the same fire, is not in it? The particular bulk, number, figure, and motion of the parts of fire and snow are really in them whether any one's senses perceive them or no; but light, heat, whiteness, or coldness, are no more in them, than sickness or pain is in manna.

The same water, at the same time, may produce the idea of cold by one hand and of heat by the other, but the same water cannot be both hot and cold at the same time. If we imagine warmth as it is in our hands, to be nothing but a certain sort and degree of motion in the minute particles of our nerves, or animal spirits, we may understand how the same water may at the same time produce the sensation of heat in one hand and cold in the other; but figure never produces the idea of square by one hand and round by the other.

The qualities that are in bodies are, 1. bulk, figure, number, situation, and motion or rest of their solid parts. These are in them whether we perceive them or no; and these I call primary qualities. 2. The power that is in any body to produce in us the ideas of color, sound, smell, taste, &c. these are called sensible qualities. 3. The power that is in any body to make a sensible change in the bulk, figure, texture, and motion of another body. Thus the sun has a power to make wax white, and fire to make lead Auid. These are usually called powers.

The first of these may be properly called primary qualities, the other two are only powers which result from the different modifications of those primary qualities.

But the second sort, viz. the power to produce ideas by our senses, are looked on as real qualities, though the third sort are esteemed barely powers. Thus light and heat are thought real qualities existing in the sun, but we look on the whiteness and softness produced in wax, not as qualities in the sun, but as effects produced by powers in it; whereas our perceptions of light and heat are no more in the sun than the changes made in the melted or bleached wax.

The reason why the one are taken for qualities and the other only for powers, is that the ideas we have of colors, sounds, &c. containing nothing of bulk, figure, or motion, we do not think them the effects

of these primary qualities; hence we imagine the ideas to be resemblances of something existing in the objects. But in the operations of bodies changing the qualities one of another, we discover in the qualities produced no resemblance to the cause producing it; for when we see wax or a fair face changed by the sun, we find not these colors in the sun itself: for our senses being able to discover the likeness or unlikeness of sensible qualities in two different external objects, we never fancy any sensible quality produced in a subject to be a quality communicated, but only an effect of bare power, unless we find such a sensible quality in the subject producing it. But our senses not discovering any unlikeness between our ideas and the qualities of objects producing them, we are apt to imagine that our ideas are resemblances of something in the objects, and not the effects of certain powers in their primary qualities.

To conclude; besides the before-mentioned primary qualities, all the rest are but powers, whereby, by immediately operating on our bodies, they produce different ideas in us; or by changing the primary qua lities of other bodies, they render them capable of producing ideas in us different from what they before did. The former may be called secondary qualities, immediately perceivable; the latter, secondary qualities, mediately perceivable.

CHAPTER IX.

Of Perception.

Perception is the first faculty exercised about ideas, and is the first idea we have from reflection. It is by some called thinking, though thinking is, in strict propriety, an active operation of the mind; while, in perception, the mind is for the most part passive.

Whatever impressions are made on the body, if they are not taken notice of within, there is no perception. Fire may burn our bodies, but unless the sense of

heat, or idea of pain, be produced in the mind, there is no actual perception. How often may a man observe, that whilst the mind is intently employed, it takes no notice of the impressions of sounding bodies! An impulse is made on the organ, but not reaching the observation of the mind, no perception follows. So that wherever there is sense or perception, there some idea is actually produced, and present to the understanding.

Children before they are born may receive some few ideas from the bodies that environ them, or from the wants and diseases they may suffer. Hunger and warmth are probably the first ideas they have. But these are very far from those innate principles which some contend for; they are the effects of sensation, and differ from other ideas derived from sense only in precedence of time. As some ideas may be introduced into the minds of children previous to their birth, so after they are born those ideas are the earliest imprinted which happen to be the sensible qualities which first occur to them, amongst which light is not the least considerable. The ideas that are most familiar at first being various according to circumstances, the order in which they come into the mind is uncertain, nor is it material to know it.

We are farther to consider concerning perception, that the ideas received by sensation are insensibly altered by the judgment. When we see a round globe, the idea imprinted on our mind is of a flat circle variously shadowed; but having been accustomed to the appearance made by convex bodies, the judgment by habitual custom alters the appearances into their causes: so that from variety of shadow it frames to itself the perception of a convex figure and uniform color; when the idea we receive thence, is only a plane variously colored; as is evident in painting. To which purpose I shall here insert a problem of the learned and worthy Mr. Molineux :- Suppose a man born blind, and now adult, and taught by his