others, he was seduced by some received hypothesis: and, that this was actually the case, will appear in the following section.

SECTION VI.

THAT NONE OF OUR SENSATIONS ARE RESEMBLANCES OF ANY OF THE QUALITIES OF BODIES.

A SECOND inference is, that although colour is really a quality of body, yet it is not represented to the mind by an idea or sensation that resembles it; on the contrary, it is suggested by an idea which does not in the least resemble it. And this inference is applicable, not to colour only, but to all the qualities of body which we have examined.

It deserves to be remarked, that in the analysis we have hitherto given of the operations of the five senses, and of the qualities of bodies discovered by them, no instance hath occurred, either of any sensation which resembles any quality of body, or of any quality of body whose image or resemblance is conveyed to the mind by means of the senses.

There is no phenomenon in nature more unaccountable, than the intercourse that is carried on between the mind and the external world: there is no phenomenon which philosophical spirits have shown greater avidity to pry into and to resolve. It is agreed by all, that this intercourse is carried on by means of the senses; and this satisfies the vulgar curiosity, but not the philosophic. Philosophers must have some system, some hypothesis, that shows the manner in which our senses make us acquainted with external things. All the fertility of human invention seems to have produced only one hypothesis for this purpose, which therefore hath been universally received: and that is, that the mind, like a mirror, receives the images of things from without, by means of the senses : so that their use must be to convey these images into the mind.

Whether to these images of external things in the mind, we give the name of sensible forms, or sensible species, with the Peripatetics, or the name of ideas of sensation, with Locke; or whether, with later philosophers, we distinguish sensations, which are immediately conveyed by the senses, from ideas of sensation, which are faint copies of our sensations retained in the memory and imagination; these are only differences about words. The hypothesis I have mentioned is common to all these different systems.

The necessary and allowed consequence of this hypothesis is, that no material thing, nor any quality of material things, can be conceived by us or made an object of thought, until its image

is conveyed to the mind by means of the senses. We shall examine this hypothesis particularly afterward, and at this time only observe, that, in consequence of it, one would naturally expect, that to every quality and attribute of body we know or can conceive, there should be a sensation corresponding, which is the image and resemblance of that quality; and that the sensations which have no similitude or resemblance to body, or to any of its qualities, should give us no conception of a material world, or of any thing belonging to it. These things might be expected as the natural consequences of the hypothesis we have mentioned.

Now we have considered, in this and the preceding chapters, extension, figure, solidity, motion, hardness, roughness, as well as colour, heat and cold, sound, taste and smell. We have endeavoured to show, that our nature and constitution lead us to conceive these as qualities of body, as all mankind have always conceived them to be. We have likewise examined, with great attention, the various sensations we have by means of the five senses, and are not able to find among them all, one single image of body, or of any of its qualities. From whence then come those images of body and of its qualities into the mind? Let philosophers resolve this question. All I can say is, that they come not by the senses. I am sure that by proper attention and care I may know my sensations, and be able to affirm with certainty what they resemble, and what they do not resemble. I have examined them one by one, and compared them with matter and its qualities; and I cannot find one of them that confesses a resembling feature.

A truth so evident as this, that our sensations are not images of matter, or of any of its qualities, ought not to yield to a hypothesis such as that above mentioned, however ancient, or however universally received by philosophers; nor can there be any amicable union between the two. This will appear by some reflections upon the spirit of the ancient and modern philosophy concerning sensation.

During the reign of the Peripatetic philosophy, our sensations were not minutely or accurately examined. The attention of philosophers, as well as of the vulgar, was turned to the things signified by them: therefore, in consequence of the common hypothesis, it was taken for granted, that all the sensations we have from external things, are the forms or images of these external things. And thus the truth we have mentioned, yielded entirely to the hypothesis, and was altogether suppressed by it.

Des Cartes gave a noble example of turning our attention inward, and scrutinizing our sensations, and this example hath been very worthily followed by modern philosophers, particularly by Malebranche, Locke, Berkeley, and Hume. The ef

fect of this scrutiny hath been a gradual discovery of the truth above mentioned, to wit, the dissimilitude between the sensations of our minds, and the qualities or attributes of an insentient inert substance, such as we conceive matter to be. But this valuable and useful discovery, in its different stages, hath still been unhappily united to the ancient hypothesis; and, from this inauspicious match of opinions, so unfriendly and discordant in their natures, have arisen those monsters of paradox and skepticism with which the modern philosophy is too justly chargeable.

Locke saw clearly, and proved incontestably, that the sensations we have by taste, smell, and hearing, as well as the sensations of colour, heat, and cold, are not resemblances of any thing in bodies; and in this he agrees with Des Cartes and Malebranche. Joining this opinion with the hypothesis, it follows necessarily, that three senses of the five are cut off from giving us any intelligence of the material world, as being altogether inept for that office. Smell, and taste, and sound, as well as colour and heat, can have no more relation to body, than anger or gratitude; nor ought the former to be called qualities of body, whether primary or secondary, any more than the latter. For it was natural and obvious to argue thus from that hypothesis: if heat, and colour, and sound, are real qualities of body, the sensations, by which we perceive them, must be resemblances of those qualities: but these sensations are not resemblances; therefore those are not real qualities of body.

We see then, that Locke, having found that the ideas of secondary qualities are no resemblances, was compelled, by a hypothesis common to all philosophers, to deny that they are real qualities of body. It is more difficult to assign a reason, why, after this, he should call them secondary qualities; for this name, if I mistake not, was of his invention. Surely he did not mean that they were secondary qualities of the mind; and I do not see with what propriety, or even by what tolerable license, he could call them secondary qualities of body, after finding that they were no qualities of body at all. In this, he seems to have

sacrificed to common sense, and to have been led by her authority, even in opposition to his hypothesis. The same sovereign mistress of our opinions that led this philosopher to call those things secondary qualities of body, which, according to his principles and reasonings, were no qualities of body at all, hath led, not the vulgar of all ages only, but philosophers also, and even the disciples of Locke, to believe them to be real qualities of body she hath led them to investigate, by experiments, the nature of colour, and sound, and heat, in bodies. Nor hath this investigation been fruitless, as it must have been, if there had been no such thing in bodies: on the contrary, it hath produced very noble and useful discoveries, which make a very consider

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able part of natural philosophy. If then natural philosophy be not a dream, there is something in bodies, which we call colour, and heat, and sound. And if this be so, the hypothesis from which the contrary is concluded must be false for the argument, leading to a false conclusion, recoils against the hypothesis from which it was drawn, and thus directs its force backward. If the qualities of body were known to us only by sensations that resemble them, then colour, and sound, and heat, could be no qualities of body; but these are real qualities of body; and therefore the qualities of body are not known only by means of sensations that resemble them.

But to proceed: what Locke had proved with regard to the sensations we have by smell, taste, and hearing, bishop Berkeley proved no less unanswerably with regard to all our other sensations; to wit, that none of them can in the least resemble the qualities of a lifeless and insentient being, such as matter is conceived to be. Mr. Hume hath confirmed this by his authority and reasoning. This opinion surely looks with a very malign aspect upon the old hypothesis; yet that hypothesis hath still been retained, and conjoined with it. And what a brood of monsters hath this produced.

The firstborn of this union, and perhaps the most harmless, was, that the secondary qualities of bodies were mere sensations of the mind. To pass by Malebranche's notion of seeing all things in the ideas of the divine mind, as a foreigner never naturalized in this island; the next was Berkeley's system, that extension, and figure, and hardness, and motion; that land, and sea, and houses, and our own bodies, as well as those of our wives, and children, and friends, are nothing but ideas of the mind; and that there is nothing existing in nature, but minds and ideas.

The progeny that followed, is still more frightful; so that it is surprising, that one could be found who had the courage to act the midwife, to rear it up, and to usher it into the world. No causes nor effects; no substances, material or spiritual; no evidence even in mathematical demonstration; no liberty nor active power; nothing existing in nature, but impressions and ideas following each other, without time, place, or subject. Surely no age ever produced such a system of opinions, justly deduced with great acuteness, perspicuity, and elegance, from a principle universally received. The hypothesis we have mentioned, is the father of them all. The dissimilitude of our sensations and feelings to external things, is the innocent mother of most of them.

As it happens sometimes in an arithmetical operation, that two errors balance one another, so that the conclusion is little or nothing affected by them; but when one of them is corrected and the other left, we are led farther from the truth, than by

both together: so it seems to have happened in the Peripatetic philosophy of sensation, compared with the modern. The Peripatetics adopted two errors'; but the last served as a corrective to the first, and rendered it mild and gentle; so that their system had no tendency to skepticism. The moderns have retained the first of those errors, but have gradually detected and corrected the last. The consequence hath been, that the light we have struck out hath created darkness, and skepticism hath advanced hand in hand with knowledge, spreading its melancholy gloom first over the material world, and at last over the whole face of nature. Such a phenomenon as this, is apt to stagger even the lovers of light and knowledge, while its cause is latent; but when that is detected, it may give hopes, that this darkness shall not be everlasting, but that it shall be succeeded by a more permanent light.

ALTHOUGH there is no resemblance, nor, as far as we know, any necessary connexion, between that quality in a body which we call its colour, and the appearance which that colour makes to the eye; it is quite otherwise with regard to its figure and magnitude. There is certainly a resemblance, and a necessary connexion, between the visible figure and magnitude of a body, and its real figure and magnitude; no man can give a reason why a scarlet colour affects the eye in the manner it does; no man can be sure that it affects his eye in the same manner as it affects the eye of another, and that it has the same appearance to him as it has to another man; but we can assign a reason why a circle placed obliquely to the eye, should appear in the form of an ellipse. The visible figure, magnitude, and position, may, by mathematical reasoning, be deduced from the real; and it may be demonstrated, that every eye that sees distinctly and perfectly, must, in the same situation, see it under this form, and no other. Nay, we may venture to affirm, that a man born blind, if he were instructed in mathematics, would be able to determine the visible figure of a body, when its real figure, distance, and position, are given. Dr. Saunderson understood the projection of the sphere, and perspective. Now, I require no more knowledge in a blind man, in order to his being able to determine the visible figure of bodies, than that he can project the outline of a given body, upon the surface of a hollow sphere, whose centre is in the eye. This projection is the visible figure he wants: for it is