in which they take it, it is indeed absurd, and so they hold it to be. In the sense in which he means it, it is true: and the vulgar, as soon as they are made to understand that sense, will acknowledge it to be true. They know as well as the philosopher, that the fire does not feel heat: and this is all that he means by saying there is no heat in the fire.

In the opinions of philosophers about primary and secondary qualities, there have been, as was before observed, several revolutions: They were distinguished, long before the days of Aristotle, by the sect called Atomists; among whom Democritus made a capital figure. In those times, the name of quality was applied only to those we call secondary qualities; the primary being considered as essential to matter, were not called qualities. That the atoms, which they held to be the first principles of things, were extended, solid, figured, and moveable, there was no doubt; but the question was, whether they had smell, taste, and colour? or, as it was commonly expressed, whether they had qualities? The atomists maintained, that they had not; that the qualities were not in bodies, but were something resulting from the operation of bodies upon our senses.

It would seem, that when men began to speculate upon this subject, the primary qualities appeared so clear and manifest, that they could entertain no doubt of their existence wherever matter existed; but the secondary so obscure, that they were at a loss where to place them. They used this comparison; as fire, which is neither in the flint nor in the steel, is produced by their collision, so those qualities, though not in bodies, are produced by their impulse upon our senses.

This doctrine was opposed by Aristotle. He believed taste and colour to be substantial forms of bodies, and that their species, as well as those of figure and motion, are received by the senses.

In believing, that what we commonly call taste and colour is something really inherent in body, and does not depend upon its being tasted and seen, he followed nature. But, in believing that our sensations of taste and colour are the forms or species of those qualities received by the senses, he followed his own theory, which was an absurd fiction. Des Cartes not only showed the absurdity of sensible species received by the senses, but gave a more just and more intelligible account of secondary qualities than had been given before. Mr. Locke followed him, and bestowed much pains upon this subject. He was the first, I think, that gave them the name of secondary qualities, which has been very generally adopted. He distinguished the sensation from the quality in the body which is the cause or occasion of that sensation, and showed that there neither is nor can be any similitude between them.

By this account, the senses are acquitted of putting any fallacy upon us; the sensation is real, and no fallacy: the quality in the body, which is the cause or occasion of this sensation, is likewise real, though the nature of it is not manifest to our senses. If we impose upon ourselves, by confounding the sensation with the quality that occasions it, this is owing to rash judgment, or weak understanding, but not to any false testimony of

our senses.

This account of secondary qualities I take to be very just; and if Mr. Locke had stopped here, he would have left the matter very clear. But he thought it necessary to introduce the theory of ideas, to explain the distinction between primary and secondary qualities, and by that means, as I think, perplexed and darkened it.

When philosophers speak about ideas, we are often at a loss to know what they mean by them, and may be apt to suspect that they are mere

fictions, that have no existence. They have told us, that, by the ideas which we have immediately from our senses, they mean our sensations. These, indeed, are real things, and not fictions. We may, by accurate ttention to them, know perfectly their nature; and if philosophers would keep by this meaning of the word idea, when applied to the objects of ense, they would at least be more intelligible. Let us hear how Mr. Locke explains the nature of those ideas, when applied to primary and secondary qualities, Book 2, chap. 8, sect. 7, 10th edition. "To discover the nature of our ideas the better, and to discourse of them intelligibly, it will be convenient to distinguish them, as they are ideas, or perceptions 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 resemblances 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."

This way of distinguishing a thing, first, as what it is; and, secondly, as what it is not, is, I apprehend, å very extraordinary way of discovering its nature and if ideas are ideas or perceptions in our minds, and at the same time the modifications of matter in the bodies that cause such perceptions in us, it will be no easy matter to discourse of them intelligibly.

The discovery of the nature of ideas is carried on in the next section, in a manner no less extraordinary. "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 snowball 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 snowball, I call qualities; and as they are sensations, or perceptions in our understandings, I call them ideas; which ideas, if I speak of them sometimes as in the things themselves, I would be understood to mean those qualities in the objects which produce them in us."

These are the distinctions which Mr. Locke thought convenient, in order to discover the nature of our ideas of the qualities of matter the better, and to discourse of them intelligibly. I believe it will be difficult to find two other paragraphs in the Essay so unintelligible. Whether this is to be imputed to the intractible nature of ideas, or to an oscitancy of the author, with which he is very rarely chargeable, I leave the reader to judge. There are, indeed, several other passages in the same chapter, in which a like obscurity appears; but I do not choose to dwell upon them. The conclusion drawn by him from the whole is, that primary and secondary qualities are distinguished by this, that the ideas of the former are resemblances or copies of them; but the ideas of the other are not resemblances of them. Upon this doctrine, I beg leave to make two observations.

First, Taking it for granted, that, by the ideas of primary and secondary qualities, he means the sensations they excite in us, I observe, that it appears strange, that a sensation should be the idea of a quality in body, to which it is acknowledged to bear no resemblance. If the sensation of sound be the idea of that vibration of the sounding body which occasions it, a surfeit may, for the same reason, be the idea of a feast.

A second observation is, That when Mr. Locke affirms, that the ideas of primary qualities, that is, the sensations they raise in us, are resemblances

of those qualities, he seems neither to have given due attention to those sensations, nor to the nature of sensation in general.

Let a man press his hand against a hard body, and let him attend to the sensation he feels, excluding from his thought every thing external, even the body that is the cause of his feeling. This abstraction indeed is difficult, and seems to have been little, if at all, practised: but it is not impossible, and it is evidently the only way to understand the nature of the sensation. A due attention to this sensation will satisfy him, that it is no more like hardness in a body, than the sensation of sound is like vibration in the sounding body.

I know of no ideas but my conceptions; and my idea of hardness in a body, is the conception of such a cohesion of its parts as requires great force to displace them. I have both the conception and belief of this quality in the body, at the same that I have the sensation of pain, by pressing my hand against it. The sensation and perception are closely conjoined by my constitution; but I am sure they have no similitude: I know no reason why the one should be called the idea of the other, which does not lead us to call every natural effect the idea of its cause.

Neither did Mr. Locke give due attention to the nature of sensation in general, when he affirmed, that the ideas of primary qualities, that is, the sensations excited by them, are resemblances of those qualities.

That there can be nothing like sensation in an insentient being, or like thought in an unthinking being, is self-evident, and has been shown, to the conviction of all men that think, by Bishop Berkeley; yet this was unknown to Mr. Locke. It is an humbling consideration, that, in subjects of this kind, self-evident truths may be hid from the eyes of the most ingenious men. But we have, withal, this consolation, that, when once discovered, they shine by their own light; and that light can no more be put out.

Upon the whole, Mr. Locke, in making secondary qualities to be powers in bodies to excite certain sensations in us, has given a just and distinct analysis of what our senses discover concerning them; but, in applying the theory of ideas to them, and to the primary qualities, he has been led to say things that darken the subject, and that will not bear examination.

Bishop Berkeley having adopted the sentiments common to philosophers, concerning the ideas we have by our senses, to wit, that they are all sensations, saw more clearly the necessary consequence of this doctrine; which is, that there is no material world; no qualities primary or secondary; and, consequently, no foundation for any distinction between them. He exposed the absurdity of a resemblance between our sensations and any quality, primary or secondary, of a substance that is supposed to be insentient. Indeed, if it is granted that the senses have no other office but to furnish us with sensations, it will be found impossible to make any distinction between primary and secondary qualities, or even to maintain the existence of a material world.

From the account I have given of the various revolutions in the opinions of philosophers about primary and secondary qualities, I think it appears, that all the darkness and intricacy that thinking men have found in this subject, and the errors they have fallen into, have been owing to the difficulty of distinguishing clearly sensation from perception; what we feel from what we perceive.

The external senses have a double province; to make us feel, and to make us perceive. They furnish us with a variety of sensations, some

- pleasant, others painful, and others indifferent; at the same time they give us a conception, and an invincible belief of the existence of external objects. This conception of external objects is the work of nature. The belief of their existence, which our senses give, is the work of nature; so likewise is the sensation that accompanies it. This conception and belief which nature produces by means of the senses, we call perception. The feeling which goes along with the perception, we call sensation. The perception and its corresponding sensation are produced at the same time. In our experience we never find them disjoined. Hence we are led to consider them as one thing, to give them one name, and to confound their different attributes. It becomes very difficult to separate them in thought, to attend to each by itself, and to attribute nothing to it which belongs to the other.

To do this requires a degree of attention to what passes in our own minds, and a talent of distinguishing things that differ, which is not to be expected in the vulgar, and is even rarely found in philosophers; so that the progress made in a just analysis of the operations of our senses has been very slow. The hypothesis of ideas, so generally adopted, hath, as I apprehend, greatly retarded this progress, and we might hope for a quicker advance, if philosophers could so far humble themselves as to believe, that in every branch of the philosophy of nature, the productions of human fancy and conjecture will be found to be dross; and that the only pure metal that will endure the test, is what is discovered by patient observation, and chaste induction.

CHAPTER XVIII.

OF OTHER OBJECTS OF PERCEPTION.

BESIDES primary and secondary qualities of bodies, there are many other immediate objects of perception. Without pretending to a complete enumeration, I think they mostly fall under one or other of the following classes. 1st, Certain states or conditions of our own bodies. 2d, Mechanical powers or forces. 3d, Chemical powers. 4th, Medical powers or virtues. 5th, Vegetable and animal powers.

That we perceive certain disorders in our own bodies by means of uneasy sensations, which nature hath conjoined with them, will not be disputed. Of this kind are toothach, headach, gout, and every distemper and hurt which we feel. The notions which our sense gives of these, have a strong analogy to our notions of secondary qualities. Both are similarly compounded, and may be similarly resolved, and they give light to each

other.

In the toothach, for instance, there is first, a painful feeling; and secondly, a conception and belief of some disorder in the tooth, which is believed to be the cause of the uneasy feeling. The first of these is a sensation, the second is perception; for it includes a conception and belief of an external object. But these two things, though of different natures, are so constantly conjoined in our experience, and in our imagination, that we consider them as one. We give the same name to both; for the toothach is the proper name of the pain we feel; and it is the proper name of the disorder in the tooth which causes that pain. If it should be made a question, whether the toothach be in the mind that feels it, or in the tooth that is affected? much might be said on both sides, while it is not observed

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that the word has two meanings. But a little reflection satisfies us, that the pain is in the mind, and the disorder in the tooth. If some philosopher should pretend to have made a discovery, that the toothach, the gout, the headach, are only sensations in the mind, and that it is a vulgar error to conceive that they are distempers of the body, he might defend his system in the same manner as those, who affirm that there is no sound nor colour nor taste in bodies, defend that paradox. But both these systems, like most paradoxes, will be found to be only an abuse of words.

We say that we feel the toothach, not that we perceive it. On the other hand, we say that we perceive the colour of a body, not that we feel it. Can any reason be given for this difference of phraseology? In answer to this question, I apprehend, that both when we feel the toothach, and when we see a coloured body, there is sensation and perception conjoined. But, in the toothach, the sensation being very painful, engrosses the attention; and therefore we speak of it, as if it were felt only, and not perceived: whereas, in seeing a coloured body, the sensation is different, and draws no attention. The quality in the body, which we call its colour, is the only object of attention; and therefore we speak of it, as if it were perceived, and not felt. Though all philosophers agree that in sceing colour there is sensation, it is not easy to persuade the vulgar, that, in seeing a coloured body, when the light is not too strong, nor the eye inflamed, they have any sensation or feeling at all.

There are some sensations which, though they are very often felt, are never attended to, nor reflected upon. We have no conception of them; and therefore, in language, there is neither any name for them, nor any form of speech that supposes their existence. Such are the sensations of colour, and all the primary qualities; and therefore those qualities are said to be perceived, but not to be felt. Taste and smell, and heat and cold, have sensations that are often agreeable or disagreeable, in such a degree as to draw our attention; and they are sometimes said to be felt, and sometimes to be perceived. When disorders of the body occasion very acute pain, the uneasy sensation engrosses the attention, and they are said to be felt, not to be perceived.

There is another question relating to phraseology, which this subject suggests. A man says, he feels pain in such a particular part of his body; in his toe, for instance. Now reason assures us, that pain, being a sensation, can only be in the sentient being, as its subject, that is, in the mind. And though philosophers have disputed much about the place of the mind; yet none of them ever placed it in the toe. What shall we say then in this case? do our senses really deceive us, and make us believe a thing which our reason determines to be impossible? I answer, first, That, when a man says he has pain in his toe, he is perfectly understood, both by himself, and those who hear him. This is all that he intends. He really feels what he and all men call a pain in the toe; and there is no deception in the matter. Whether therefore there be any impropriety in the phrase or not, is of no consequence in common life. It answers all the ends of speech, both to the speaker and the hearers.

In all languages, there are phrases which have a distinct meaning: while, at the same time, there may be something in the structure of them that disagrees with the analogy of grammar, or with the principles of philosophy. And the reason is, because language is not made either by grammarians or philosophers. Thus we speak of feeling pain, as if pain was something distinct from the feeling of it. We speak of a pain coming and going, and removing from one place to another. Such phrases are meant