on both sides, that this same material world, if any such there be, must be the express image of our sensations: that we can have no conception of any material thing which is not like some sensation in our minds; and particularly, that the sensations of touch are images of extension, hardness, figure, and motion. Every argument brought against the existence of a material world, either by the bishop of Cloyne or by the author of the Treatise of Human Nature, supposeth this. If this is true,

their arguments are conclusive and unanswerable: but, on the other hand, if it is not true, there is no shadow of argument left. Have those philosophers, then, given any solid proof of this hypothesis, upon which the whole weight of so strange a system rests? No. They have not so much as attempted to do it. But, because ancient and modern philosophers have agreed in this opinion, they have taken it for granted. But let us, as becomes philosophers, lay aside authority; we need not surely consult Aristotle or Locke, to know whether pain be like the point of a sword. I have as clear a conception of extension, hardness, and motion, as I have of the point of a sword; and, with some pains and practice, I can form as clear a notion of the other sensations of touch as I have of pain. When I do so, and compare them together, it appears to me clear as daylight, that the former are not of kin to the latter, nor resemble them in any one feature. They are as unlike, yea, as certainly and manifestly unlike, as pain is to the point of a sword. It may be true, that those sensations first introduced the material world to our acquaintance; it may be true, that it seldom or never appears without their company; but, for all that, they are as unlike as the passion of anger is to those features of the countenance which attend it.

So that, in the sentence those philosophers have passed against the material world, there is an error personæ. Their proof touches not matter, or any of its qualities; but strikes directly against an idol of their own imagination, a material world made of ideas and sensations, which never had nor can have an existence.

Secondly, the very existence of our conceptions of extension, figure, and motion, since they are neither ideas of sensation nor reflection, overturns the whole ideal system, by which the material world hath been tried and condemned: so that there hath been likewise in this sentence an error juris.

It is a very fine and a just observation of Locke, that as no human art can create a single particle of matter, and the whole extent of our power over the material world, consists in compounding, combining, and disjoining, the matter made to our hands; so in the world of thought, the materials are all made by nature, and can only be variously combined and disjoined by us.

So that it is impossible for reason or prejudice, true or

false philosophy, to produce one simple notion or conception, which is not the work of nature, and the result of our constitution. The conception of extension, motion, and the other attributes of matter, cannot be the effect of error or prejudice; it must be the work of nature. And the power or faculty, by which we acquire those conceptions, must be something different from any power of the human mind that hath been explained, since it is neither sensation nor reflection.

This I would therefore humbly propose, as an experimentum crucis, by which the ideal system must stand or fall; and it brings the matter to a short issue: extension, figure, motion, may, any one, or all of them, be taken for the subject of this experiment. Either they are ideas of sensation, or they are not. If any one of them can be shown to be an idea of sensation, or to have the least resemblance to any sensation, I lay my hand upon my mouth, and give up all pretence to reconcile reason to common sense in this matter, and must suffer the ideal skepticism to triumph. But if, on the other hand, they are not ideas of sensation, nor like to any sensation, then the ideal system is a rope of sand, and all the laboured arguments of the skeptical philosophy, against a material world, and against the existence of every thing but impressions and ideas, proceed upon a false hypothesis.

If our philosophy concerning the mind be so lame with regard to the origin of our notions of the clearest, most simple, and most familiar objects of thought, and the powers from which they are derived, can we expect that it should be more perfect in the account it gives of the origin of our opinions and belief? We have seen already some instances of its imperfection in this respect and perhaps that same nature which hath given us the power to conceive things altogether unlike to any of our sensations, or to any operation of our minds, hath likewise provided for our belief of them, by some part of our constitution hitherto not explained.

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Bishop Berkeley hath proved, beyond the possibility of reply, that we cannot by reasoning infer the existence of matter from our sensations: and the author of the Treatise of Human Nature hath proved no less clearly, that we cannot by reasoning infer the existence of our own or other minds from our sensations. But are we to admit nothing but what can be proved by reasoning? then we must be skeptics indeed, and believe nothing at all. The author of the Treatise of Human Nature appears to me to be but a half skeptic. He hath not followed his principles so far as they lead him but after having, with unparalleled intrepidity and success, combated vulgar prejudices; when he had but one blow to strike, his courage fails him, he fairly lays down his arms, and yields himself a captive to the most common of all vulgar prejudices, I mean the belief of the existence of his own impressions and ideas.

I beg, therefore, to have the honour of making an addition to the skeptical system, without which, I conceive it cannot hang together. I affirm, that the belief of the existence of impressions and ideas, is as little supported by reason, as that of the existence of minds and bodies. No man ever did, or could offer any reason for this belief. Des Cartes took it for granted, that he thought, and had sensations and ideas: so have all his followers done. Even the hero of skepticism hath yielded this point, I crave leave to say, weakly and imprudently. I say so, because I am persuaded that there is no principle of his philosophy that obliged him to make this concession. And what is there in impressions and ideas so formidable, that this all-conquering philosophy, after triumphing over every other existence, should pay homage to them? Besides, the concession is dangerous; for belief is of such a nature, that if you leave any root, it will spread; and you may more easily pull it up altogether, than say, Hitherto shalt thou go, and no further; the existence of impressions and ideas I give up to thee; but see thou pretend to nothing more. A thorough and consistent skeptic will never, therefore, yield this point; and while he holds it, you can never oblige him to yield any thing else.

To such a skeptic I have nothing to say; but of the semiskeptics, I should beg leave to know, why they believe the exist ence of their impressions and ideas. The true reason I take to be, because they cannot help it; and the same reason will lead them to believe many other things.

All reasoning must be from first principles; and for first principles no other reason can be given but this, that, by the constitution of our nature, we are under a necessity of assenting to them. Such principles are parts of our constitution, no less than the power of thinking: reason can neither make nor destroy them; nor can it do any thing without them: it is like a telescope, which may help a man to see farther, who hath eyes; but without eyes, a telescope shows nothing at all. A mathematician cannot prove the truth of his axioms, nor can he prove any thing, unless he takes them for granted. We cannot prove the existence of our minds, nor even of our thoughts and sensations. A historian, or a witness, can prove nothing, unless it is taken for granted that the memory and senses may be trusted. A natural philosopher can prove nothing, unless it is taken for granted that the course of nature is steady and uniform.

How or when I got such first principles, upon which I build all my reasoning, I know not; for I had them before I can remember: but I am sure they are parts of my constitution, and that I cannot throw them off. That our thoughts and sensations must have a subject, which we call ourself, is not therefore an opinion got by reasoning, but a natural principle. That our sensations of touch indicate something external, extended, fig

ured, hard, or soft, is not a deduction of reason, but a natural principle. The belief of it, and the very conception of it, are equally parts of our constitution. If we are deceived in it, we are deceived by him that made us, and there is no remedy.

I do not mean to affirm, that the sensations of touch do from the very first suggest the same notions of body and its qualities, which they do when we are grown up. Perhaps nature is frugal in this, as in her other operations. The passion of love, with all its concomitant sentiments and desires, is naturally suggested by the perception of beauty in the other sex. Yet the same perception does not suggest the tender passion till a certain period of life. A blow given to an infant, raises grief and lamentation; but when he grows up, it as naturally stirs resentment, and prompts him to resistance. Perhaps a child in the womb, or for some short period of its existence, is merely a sentient being the faculties, by which it perceives an external world, by which it reflects on its own thoughts, and existence, and relation to other things, as well as its reasoning and moral faculties, unfold themselves by degrees; so that it is inspired with the various principles of common sense as with the passions of love and resentment, when it has occasion for them.

SECTION VIII.

OF THE SYSTEMS OF PHILOSOPHERS CONCERNING THE SENSES.

ALL the systems of philosophers about our senses and their objects have split upon this rock, of not distinguishing properly sensations which can have no existence but when they are felt, from the things suggested by them. Aristotle, with as distinguishing a head as ever applied to philosophical disquisitions, confounds these two; and makes every sensation to be the form, without the matter, of the thing perceived by it: as the impression of a seal upon wax has the form of the seal, but nothing of the matter of it; so he conceived our sensations to be impressions upon the mind, which bear the image, likeness, or form of the external thing perceived, without the matter of it. Colour, sound, and smell, as well as extension, figure, and hardness, are, according to him, various forms of matter: our sensations are the same forms imprinted on the mind, and perceived in its own intellect. It is evident from this that Aristotle made no distinction between primary and secondary qualities of bodies, although that distinction was made by Democritus, Epicurus, and others of the ancients.

Des Cartes, Malebranche, and Locke, revived the distinction between primary and secondary qualities. But they made the

secondary qualities mere sensations, and the primary ones resemblances of our sensations. They maintained that colour, sound, and heat, are not any thing in bodies, but sensations of the mind at the same time, they acknowledged some particular texture or modification of the body, to be the cause or occasion of those sensations; but to this modification they gave no name. Whereas by the vulgar, the names of colour, heat, and sound, are but rarely applied to the sensations, and most commonly to those unknown causes of them; as hath been already explained. The constitution of our nature leads us rather to attend to the things signified by the sensation, than to the sensation itself, and to give a name to the former rather than to the latter. Thus we see, that with regard to secondary qualities, these philosophers thought with the vulgar, and with common sense. Their paradoxes were only an abuse of words. For when they maintain, as an important modern discovery, that there is no heat in the fire, they mean no more than that the fire does not feel heat, which every one knew before.

With regard to primary qualities, these philosophers erred more grossly they indeed believed the existence of those qualities ; but they did not at all attend to the sensations that suggest them, which having no names, have been as little considered as if they had no existence. They were aware, that figure, extension, and hardness, are perceived by means of sensations of touch; whence they rashly concluded, that these sensations must be images and resemblances of figure, extension, and hardness.

The received hypothesis of ideas naturally led them to this conclusion; and indeed cannot consist with any other; for, according to that hypothesis, external things must be perceived by means of images of them in the mind; and what can those images of external things in the mind be, but the sensations by which we perceive them?

This however was to draw a conclusion from a hypothesis against fact. We need not have recourse to any hypothesis to know what our sensations are, or what they are like. By a proper degree of reflection and attention, we may understand them perfectly, and be as certain that they are not like any quality of body, as we can be, that the toothach is not like a triangle. How a sensation should instantly make us conceive and believe the existence of an external thing altogether unlike to it, I do not pretend to know; and when I say that the one suggests the other, I mean not to explain the manner of their connexion, but to express a fact, which every one may be conscious of; namely, that, by a law of our nature, such a conception and belief constantly and immediately follow the sensation. Bishop Berkeley gave new light to this subject, by showing, that the qualities of an inanimate thing, such as matter is con

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