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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 time 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 shewn, 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. [247]

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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

No; not Sensations in Reid's meaning; but Percepts the immediate objects we are conscious of in the cognitions of sense.-H.

1 The Cartesians did not apply the term ideas to our sensations of the secondary qualities.-H.

↑ See above, p. 142, note *. The mere distinction of primary and secondary qualities, of perception and sensation, is of no importance against Idealism, if the primary qualities as immediately perceived. (ie. as known to consciousness,) be only conceptions, no tions, or modications of mind itself. See following Note.-H.

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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 sensa tion 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." [248] 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 en dure the test, is what is discovered by patient observation and chaste induction.

*If the conception, like the belief, be subjective in perception, we have no refuge from Idealism in this doctrine. See above, the notes at pp. 128-130, 183, &c., and Note C.-H.

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 of virtues. 5th, Vegetable and animal powers. [249]

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 toothache, headache, 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.

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In the toothache, 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 toothache 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 toothache 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 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 the discovery that the toothache, the gout, the headache, 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

*There is no such perception, properly so called. The cognition is merely an inference from the feeling; and its object, at least, only some hypothetical representation of a really ignotum quid." Here the subjective element preponderates so greatly as almost to extinguish the objective.-H.

This is not correct. See above, p. 205,.col. b note*, and Note D.-H.

paradoxes, will be found to be only an abus of words.

We say that we feel the toothache, 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? [250] In answer to this question, I apprehend that, both when we feel the toothache and when we see a coloured body, there is sensation and perception conjoined. But, in the toothache, 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 indifferent, 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 seeing 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 of all 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 sensaation 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 parti cular 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.+

As already repeatedly observed, the objective (feeling, sensation) are always in the inverse ratio element (perception) and the subjective element

of each other. This is a law of which Reid and the philosophers were not aware.-H.

Not in the toe exclusively. But, both in ancient and modern times, the opinion has been held that the mind has as much a local presence in the toe as in the head. The doctrine, indeed, long generally maintained was, that in relation to the body, the soul is all in the whole, and all in every part. On the question of the seat of the soul, which has been marvellously perplexed, I cannot enter. I shall only say, in general, that the first condition of the possibility of an

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? [251] 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 pain coming and going, and removing from one place to another. Such phrases are meant by those who use them in a sense that is neither obscure nor false. But the philosopher puts them into his alembic, reduces them to their first principles, draws out of them a sense that was never meant, and so imagines that he has discovered an error of the vulgar.

I observe, secondly, That, when we consider the sensation of pain by itself, without any respect to its cause, we cannot say with propriety, that the toe is either the place or the subject of it. But it ought to be remembered, that, when we speak of pain in the toe, the sensation is combined in our thought, with the cause of it, which really is in the toe. The cause and the effect are combined in one complex notion, and the same name serves for both. It is the business of the philosopher to analyse this complex notion, and to give different names to its different ingredients. He gives the name of pain to the sensation only, and the name of disorder to the unknown cause of it. Then it is evident that the disorder only is in the toe, and that it would be an error to think that the pain is in it." But we ought not to ascribe this error to the vulgar, who never made the distinction, and who, under the name of pain, comprehend both the sensation and its cause.+ [252]

immediate, intuitive, or real perception of external things, wh ch our consciousness assures that we possess, is the immediate connection of the cognitive principle with every part of the corporeal organism.H.

*Only if the toe be considered as a mere material mass, and apart from an animating principle.-H.

That the pain is where it is felt is, however, the doctrine of common sense. We only feel in as much as we have a body and a soul; we only feel pain in the toe in as much as we have such a member, and in

Cases sometimes happen, which give occasion even to the vulgar to distinguish the painful sensation from the disorder which is the cause of it. A man who has had his leg cut off, many years after feels pain in a toe of that leg. The toe has now no existence; and he perceives easily, that the toe can neither be the place nor the subject of the pain which he feels; yet it is the same feeling he used to have from a hurt in the toe; and, if he did not know that his leg was cut off, it would give him the same immediate conviction of some hurt or disorder in the toe.*

The same phenomenon may lead the philosopher, in all cases, to distinguish sensation from perception. We say, that the man had a deceitful feeling, when he felt a pain in his toe after the leg was cut off; and we have a true meaning in saying so. But, if we will speak accurately, our sensations cannot be deceitful; they must be what we feel them to be, and can be nothing else. Where, then, lies the deceit ? I answer, it lies not in the sensation, which is real, but in the seeming perception he had of a disorder in his toe. This perception, which Nature had conjoined with the sensation, was, in this instance, fallacious.

The same reasoning may be applied to every phenomenon that can, with propriety, be called a deception of sense. As when one who has the jaundice sees a body yellow, which is really white;† or when a man sees an object double, because his eyes are not both directed to it: in these, and other like cases, the sensations we have are real, and the deception is only in the perception which nature has annexed to them.

Nature has connected our perception of external objects with certain sensations. If the sensation is produced, the corresponding perception follows even when there is no object, and in that case is apt to deceive us. [253] In like manner, nature has connected our sensations with certain impressions that are made upon the nerves and brain; and, when the impression is made, from whatever cause, the corresponding sensation and perception immediately follow. Thus, in the man who feels pain in his toe after the leg is cut off, the nerve that went to the toe, part of which was cut off with the leg, had the same impres sion made upon the remaining part, which, in the natural state of his body, was caused

as much as the mind, or sentient principle, pervades it. We just as much feel in the toe as we think in in the head. If (but only if) the latter be a vitium subreptionis, as Kant thinks, so is the former.-H.

This illustration is Des Cartes'. If correct, it only shews that the connection of mind with organ. ization extends from the centre to the circumference of the nervous system, and is not limited to any pa-H.

↑ The man does not see the white body at all.- H.

by a hurt in the toe and immediately this impression is followed by the sensation and perception which nature connected with it." In like manner, if the same impressions which are made at present upon my optic nerves by the objects before me, could be made in the dark, I apprehend that I should have the same sensations and see the same objects which I now see. The impressions and sensations would in such a case be real, and the perception only fallacious.* Let us next consider the notions which our senses give us of those attributes of bodies called powers. This is the more necessary, because power seems to imply some activity; yet we consider body as a dead inactive thing, which does not act, but may be acted upon.

Of the mechanical powers ascribed to bodies, that which is called their vis insita or inertia, may first be considered. By this is meant, no more than that bodies never change their state of themselves, either from rest to motion, or from motion to rest, or from one degree of velocity or one direction to another. In order to produce any such change, there must be some force impressed upon them; and the change produced is precisely proportioned to the force impressed, and in the direction of that force.

That all bodies have this property, is a matter of fact, which we learn from daily observation, as well as from the most accurate experiments.. [254] Now, it seems plain, that this does not imply any activity in body, but rather the contrary. A power in body to change its state, would much rather imply activity than its continuing in the same state: so that, although this property of bodies is called their vis insita, or vis inertia, it implies no proper activity.

If we consider, next, the power of gravity, it is a fact that all the bodies of our planetary system gravitate towards each other. This has been fully proved by the great Newton. But this gravitation is not conceived by that philosopher to be a power inherent in bodies, which they exert of themselves, but a force impressed upon them, to which they must necessarily yield. Whether this force be impressed by some subtile æther, or whether it be impressed by the power of the Supreme Being, or of some subordinate spiritual being, we do not know; but all sound natural philosophy, particularly that of Newton, supposes it to be an impressed force, and not inherent in bodies. + So that, when bodies gravitate, they do

*This is a doctrine which cannot be reconciled

with that of an intuitive or objective perception.

All here is subjective.-H.

That all activity supposes an immaterial or spiritual agent, is an ancient doctrine. It is, however, only an hypothesis.-H.

not properly act, but are acted upon: they only yield to an impression that is made upon them. It is common in language to express, by active verbs, many changes in things wherein they are merely passive: and this way of speaking is used chiefly when the cause of the change is not obvious to sense. Thus we say that a ship sails, when every man of common sense knows that she has no inherent power of motion, and is only driven by wind and tide. In like manner, when we say that the planets gravitate towards the sun, we mean no more but that, by some unknown power, they are drawn or impelled in that direction.

What has been said of the power of gravitation may be applied to other mechanical powers, such as cohesion, magnetism, electricity; and no less to chemical and medical powers. By all these, certain effects are produced, upon the application of one body to another. [255] Our senses discover the effect; but the power is latent. We know there must be a cause of the effect, and we form a relative notion of it from its effect; and very often the same name is used to signify the unknown cause, and the known effect.

We ascribe to vegetables the powers of drawing nourishment, growing and multiplying their kind. Here likewise the effect is manifest, but the cause is latent to sense. These powers, therefore, as well as all the other powers we ascribe to bodies, are unknown causes of certain known effects. It is the business of philosophy to investigate the nature of those powers as far as we are able; but our senses leave us in the dark.

We may observe a great similarity in the notions which our senses give us of secondary qualities, of the disorders we feel in our own bodies, and of the various powers of bodies which we have enumerated. They are all obscure and relative notions, being a conception of some unknown cause of a known effect. Their names are, for the most part, common to the effect and to its cause; and they are a proper subject of philosophical disquisition. They might, therefore, I think, not improperly be called occult qualities.

This name, indeed, is fallen into disgrace since the time of Des Cartes. It is said to have been used by the Peripatetics to cloak their ignorance, and to stop all inquiry into the nature of those qualities called occult. Be it so.

Let those answer for this abuse of the word who were guilty of it. To call a thing occult, if we attend to the meaning of the word, is rather modestly to confess ignorance, than to cloak it. It is to point it out as a proper subject for the investigation of philosophers, whose proper business it is to better the condition of humanity, by discovering what was before hid from human knowledge. [256]

Were I therefore to make a division of the qualities of bodies as they appear to our senses, I would divide them first into those that are manifest and those that are occult. The manifest qualities are those which Mr Locke calls primary; such as Extension, Figure, Divisibility, Motion, Hardness, Softness, Fluidity. The nature of these is manifest even to sense; and the business of the philosopher with regard to them, is not to find out their nature, which is well known, but to discover the effects produced by their various combinations; and, with regard to those of them which are not essential to matter, to discover their causes as far as he is able.

The second class consists of occult qualities, which may be subdivided into various kinds: as, first, the secondary qualities; secondly, the disorders we feel in our own bodies; and, thirdly, all the qualities which we call powers of bodies, whether mechanical, chemical, medical, animal, or vegetable; or if there be any other powers not comprehended under these heads. Of all these the existence is manifest to sense, but the nature is occult; and here the philosopher has an ample field.

What is necessary for the conduct of our animal life, the bountiful Author of Nature hath made manifest to all men. But there are many other choice secrets of Nature, the discovery of which enlarges the power and exalts the state of man. These are left to be discovered by the proper use of our rational powers. They are hid, not that they may be always concealed from human knowledge, but that we may be excited to search for them. This is the proper business of a philosopher, and it is the glory of a man, and the best reward of his labour, to discover what Nature has thus concealed. [257]

CHAPTER XIX.

OF MATTER AND OF SPACE.

THE objects of sense we have hitherto considered are qualities. But qualities must have a subject. We give the names of matter, material substance, and body, to the subject of sensible qualities; and it may be asked what this matter is.

I perceive in a billiard ball, figure, colour, and motion; but the ball is not figure, nor is it colour, nor motion, nor all these taken together; it is something that has figure, and colour, and motion. This is a dictate of nature, and the belief of all mankind.

As to the nature of this something, I am afraid we can give little account of it, but that it has the qualities which our senses discover.

But how do we know that they are qualities, and cannot exist without a subject? I confess I cannot explain how we know that they cannot exist without a subject, any more than I can explain how we know that they exist. We have the information of nature for their existence; and I think we have the information of nature that they are qualities.

The belief that figure, motion, and colour are qualities, and require a subject, must either be a judgment of nature, or it must be discovered by reason, or it must be a prejudice that has no just foundation. There are philosophers who maintain that it is a mere prejudice; that a body is nothing but a collection of what we call sensible qualities; and that they neither have nor need any subject. This is the opinion of Bishop Berkeley and Mr Hume; and they were led to it by finding that they had not in their minds any idea of substance. [258] It could neither be an idea of sensation nor of reflection.

But to me nothing seems more absurd than that there should be extension without anything extended, or motion without anything moved; yet I cannot give reasons for my opinion, because it seems to me selfevident, and an immediate dictate of my

nature.

And that it is the belief of all mankind, appears in the structure of all languages; in which we find adjective nouns used to express sensible qualities. It is well known that every adjective in language must belong to some substantive expressed or understood that is, every quality must belong to some subject.

Sensible qualities make so great a part of the furniture of our minds, their kinds are so many, and their number so great, that, if prejudice, and not nature, teach us to ascribe them all to a subject, it must have a great work to perform, which cannot be accomplished in a short time, nor carried on to the same pitch in every individual. We should find not individuals only, but nations and ages, differing from each other in the progress which this prejudice had made in their sentiments; but we find no such difference among men. What one man accounts a quality, all men do, and ever did.

It seems, therefore, to be a judgment of nature, that the things immediately perceived are qualities, which must belong to a subject; and all the information that our senses give us about this subject, is, that it is that to which such qualities belong. From this it is evident, that our notion of body or matter, as distinguished from its qualities, is a relative notion; and I am

That is our notion of absolute body is relative. This is incorrectly expressed. We can know, we can

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