the reason of this may be, that the appearances of the same colour are so various and changeable, according to the different modifications of the light, of the medium, and of the eye, that language could not afford names for them. And, indeed, they are so little interesting, that they are never attended to, but serve only as signs to introduce the things signified by them. Nor ought it to appear incredible, that appearances so frequent and so familiar should have no names, nor be made objects of thought; since we have before shewn that this is true of many sensations of familiar. Section V. AN INFERENCE FROM THE PRECEDING. and not to the idea, that we give the name of colour.* The various colours, although in their nature equally unknown, are easily distinguished when we think or speak of them, by being associated with the ideas which they excite. In like manner, gravity, magnetism, and electricity, although all unknown qualities, are distinguished by their different effects. As we grow up, the mind acquires a habit of passing so rapidly from the ideas of sight to the external things suggested by them, that the ideas are not in the least attended to, nor have they names given them in common language. When we think or speak of any parti-touch, which are no less frequent nor less cular colour, however simple the notion may seem to be which is presented to the imagination, it is really in some sort compounded. It involves an unknown cause and a known effect. The name of colour belongs indeed to the cause only, and not to the effect. But, as the cause is unknown, we can form no distinct conception of it but by its relation to the known effect; and, therefore, both go together in the imagination, and are so closely united, that they are mistaken for one simple object of thought.+ When I would conceive those colours of bodies which we call scarlet and blue-if I conceived them only as unknown qualities, I could perceive no distinction between the one and the other. I must, therefore, for the sake of distinction, join to each of them, in my imagination, some effect or some relation that is peculiar; and the most obvious distinction is, the appearance which one and the other makes to the eye. Hence the appearance is, in the imagination, so closely united with the quality called a scarlet-colour, that they are apt to be mistaken for one and the same thing, although they are in reality so different and so unlike, that one is an idea in the mind, the other is a quality of body. I conclude, then, that colour is not a sensation, but a secondary quality of bodies, in the sense we have already explained; that it is a certain power or virtue in bodies, that in fair daylight exhibits to the eye an appearance which is very familiar to us, although it hath no name. Colour differs from other secondary qualities in this, that, whereas the name of the quality is sometimes given to the sensation which indicates it, and is occasioned by it, we never, as far as I can judge, give the name of colour to the sensation, but to the quality only. Perhaps *+ It is justly observed by Mr Stewart, that these passages seem inconsistent with each other. If in the perception of colour, the sensation and the quality be so closely united as to be mistaken for one simple object of thought," does it not obviously follow, that it is to this compounded notion the name of colour must in general be given? On the other hand, when it is said that the name of colour is never given to the sensation, but to the quality only, does not this imply, that every time the word is pronounced, the quality is separated from From what hath been said about colour, we may infer two things. The first is, that one of the most remarkable paradoxes of modern philosophy, which hath been universally esteemed as a great discovery, is, in reality, when examined to the bottom, nothing else but an abuse of words. The paradox I mean is, That colour is not a quality of bodies, but only an idea in the mind. We have shewn, that the word colour, as used by the vulgar, cannot signify an idea in the mind, but a permanent quality of body. We have shewn, that there is really a permanent quality of body, to which the common use of this word exactly agrees. Can any stronger proof be desired, that this quality is that to which the vulgar give the name of colour? If it should be said, that this quality, to which we give the name of colour, is unknown to the vulgar, and, therefore, can have no name among them, I answer, it is, indeed, known only by its effects-that is, by its exciting a certain idea in us; but are there not numberless qualities of bodies which are known only by their effects, to which, notwithstanding, we find it necessary to give names? Medicine alone might furnish us with a hundred instances of this kind. Do not the words astringent, narcotic, epispastic, caustic, and innumerable others, signify qualities of bodies, which are known only by their effects upon animal bodies? Why, then, should not the vulgar give a name to a quality, whose effects are every moment perceived by their eyes? We have all the reason, therefore, that the nature of the thing admits, to think that the vulgar apply the name of colour to that quality of bodies which excites in us what the sensation, even in the imagination of the vul. gar?-H. the philosophers call the idea of colour. And that that there is such a quality in bodies, all philosophers allow, who allow that there is any such thing as body. Philosophers have thought fit to leave that quality of bodies which the vulgar call colour, without a name, and to give the name of colour to the idea or appearance, to which, as we have shewn, the vulgar give no name, because they never make it an object of thought or reflection. Hence it appears, that, when philosophers affirm that colour is not in bodies, but in the mind, and the vulgar affirm that colour is not in the mind, but is a quality of bodies, there is no difference between them about things, but only about the meaning of a word. The vulgar have undoubted right to give names to things which they are daily conversant about; and philosophers seem justly chargeable with an abuse of language, when they change the meaning of a common word, without giving warning. If it is a good rule, to think with philosophers and speak with the vulgar, it must be right to speak with the vulgar when we think with them, and not to shock them by philosophical paradoxes, which, when put into common language, express only the common sense of mankind. If you ask a man that is no philosopher, what colour is, or what makes one body appear white, another scarlet, he cannot tell. He leaves that inquiry to philosophers, and can embrace any hypothesis about it, except that of our modern philosophers, who affirm that colour is not in body, but only in the mind. Nothing appears more shocking to his apprehension, than that visible objects should have no colour, and that colour should be in that which he conceives to be invisible. Yet this strange paradox is not only universally received, but considered as one of the noblest discoveries of modern philosophy. The ingenious Addison, in the Spectator, No. 413, speaks thus of it :"I have here supposed that my reader is acquainted with that great modern discovery, which is at present universally acknowledged by all the inquirers into natural philosophy-namely, that light and colours, as apprehended by the imagination, are only ideas in the mind, and not qualities that have any existence in matter. As this is a truth which has been proved incontestably by many modern philosophers, and is, indeed, one of the finest speculations in that science, if the English reader would see the notion explained at large, he may find it in the eighth chapter of the second book of Locke's Essay on Human Understanding." 999 Mr Locke and Mr Addison are writers who have deserved so well of mankind, that one must feel some uneasiness in differing from them, and would wish to ascribe all the merit that is due to a discovery upon which they put so high a value. And, indeed, it is just to acknowledge that Locke, and other modern philosophers, on the subject of secondary qualities, have the merit of distinguishing more accurately than those that went before them, between the sensation in the mind, and that constitution or quality of bodies which gives occasion to the sensation. They have shewn clearly that these two things are not only distinct, but altogether unlike that there is no similitude between the effluvia of an odorous body and the sensation of smell, or between the vibrations of a sounding body and the sensation of sound: that there can be no resemblance between the feeling of heat, and the constitution of the heated body which occasions it; or between the appearance which a coloured body makes to the eye, and the texture of the body which causes that appearance. : Nor was the merit small of distinguishing these things accurately; because, however different and unlike in their nature, they have been always so associated in the imagination, as to coalesce, as it were, into one two-faced form, which, from its amphibious nature, could not justly be appropriated either to body or mind; and, until it was properly distinguished into its different constituent parts, it was impossible to assign to either their just shares in it. None of the ancient philosophers had made this distinction. The followers of Democritus and Epicurus conceived the forms of heat, and sound, and colour, to be in the mind only; but that our senses fallaciously represented them as being in bodies. The Peripatetics imagined that those forms are really in bodies; and that the images of them are conveyed to the mind by our senses. + The one system made the senses naturally fallacious and deceitful; the other made the qualities of body to resemble the sensations of the mind. Nor was it possible to find a third, without making the distinction we have mentioned; by which, indeed, the errors of both these ancient systems are avoided, and we are not left under the hard necessity of believing, either, on the one hand, that our sensations are like to the qualities of body, or, on the other, that God hath given us one faculty to deceive us, and another to detect the cheat. This is inaccurate. The distinction was known to the ancient philosophers; and Democritus was generally allowed to be its author. This Reid himself elsewhere indeed admits.-(See above, p. 123, a; ard P. 131, a.)-H. + These statements concerning both classes of philosophers are vague and incorrect. The latter, in general, only allowed species for two senses, Sight and Hearing; few admitted them in Feeling; and some rejected them altogether.-H. We desire, therefore, with pleasure, to do justice to the doctrine of Locke, and other modern philosophers, with regard to colour and other secondary qualities, and to ascribe to it its due merit, while we beg leave to censure the language in which they have expressed their doctrine. When they had explained and established the distinction between the appearance which colour makes to the eye, and the modifica tion of the coloured body which, by the laws of nature, causes that appearance, the question was, whether to give the name of colour to the cause or to the effect? By giving it, as they have done, to the effect, they set philosophy apparently in opposition to common sense, and expose it to the ridicule of the vulgar. But had they given the name of colour to the cause, as they ought to have done, they must then have affirmed, with the vulgar, that colour is a quality of bodies; and that there is neither colour nor anything like it in the mind. Their language, as well as their sentiments, would have been perfectly agreeable to the common appreliensions of mankind, and true Philosophy would have joined hands with Common Sense. As Locke was no enemy to common sense, it may be presumed, that, in this instance, as in some others, he was seduced by some received hypothesis; and that this was actually the case, will appear in the following section. Section VI. 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 shews 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;t 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 afterwards, and at this time only observe, that, in consequence of it, one would naturally THAT NONE OF OUR SENSATIONS ARE RE- expect, that to every quality and attribute SEMBLANCES 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. 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 anything 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, It deserves to be remarked, that, in the Solidity, Motion, Hardness, Roughness, as analysis we have hitherto given of the ope- well as Colour, Heat, and Cold, Sound, rations of the five senses, and of the quali-Taste, and Smell. We have endeavoured ties 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. to shew that our nature and constitution lead us to conceive these as qualities of body, as all mankind have always con This is incorrect, especially as it asserts that the one universal hypothesis of philosophy was, that "the mind receives the images of things from without," meaning by these images, immediate or representative objects, different from the modifications of the thinking subject itself.-H. There is no phænomenon in nature more unaccountable than the intercourse that is carried on between the mind and the external world-there is no phænomenon which philosophical spirits have shewning sense.-H. +He refers to Hume; Aristotle, however, and Hobbes, had previously called Imagination a decay. ceived 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 effect 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 scepticism 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 #One single-a common but faulty pleonasm.-H. sensations of colour, heat, and cold, are not resemblances of anything 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 considerable 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 con The terms First and Second, or Primary and Secondary qualities, were no more an invention of Locke than the distinction which he applied them to denote. The terms First and Second Qualities, as I have noticed, in the Aristotelian philosophy, marked out, however, a different distribution of qualities than that in question.-H. trary 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. 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! Mr The first-born of this union, and, perhaps, the most harmless, was, That the secondary qualities of body 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. Bayle, before Berkeley, shewed that the reason. ing of Malebranche against the external reality of the secondary qualities, when carried to its legitimate issue, subverted also that of the primary.-H. + Malebranche, it should be observed, distin. guished more precisely than Des Cartes, or any previous philosopher, primary from secondary qualities; and perception (idée) from sensation (sentiment.) He regarded the sensation of the secondary qualities as the mere subjective feeling which the human mind had of its own affections; but the perception of the primary he considered as an objective intuition it obtained of these, as represented in the divine mind-H. 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 scepticism. 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 scepticism 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 phænomenon 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. Section VII. OF VISIBLE FIGURE AND EXTENSION. Although there is no resemblance, nor, as far as we know, any necessary connection, 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 connection, 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 |