Section IV.

OF HARDNESS, AND OTHER PRIMARY

QUALITIES.

Further, I observe that hardness is a quality, of which we have as clear and distinct a conception as of anything whatsoever. The cohesion of the parts of a body with more or less force, perfectly understood, though its cause is not; we know what it is, as well as how it affects the touch. It is, therefore, a quality of a quite different order from those secondary qualities we have already taken notice of, whereof we know no more naturally than that they are adapted to raise certain sensations in us. If hardness were a quality of the same kind, it would be a proper inquiry for philosophers, what hardness in bodies is ? and we should have had various hypotheses about it, as well as about colour and heat. But it is evident that any such hypothesis would be ridiculous. If any man should say, that hardness in bodies is a certain vibration of their parts, or that it is certain effluvia emitted by them which affect our touch in the manner we feel-such hypotheses would shock common sense; because we all know that, if the parts of a body adhere strongly, it is hard, although it should neither emit effluvia nor vibrate. Yet, at the same time, no man can say, but that effluvia, or the vibration of the parts of a body, might have affected our touch, in the same manner that hardness now does, if it had so pleased the Author of our nature; and, if either of these hypotheses is applied to explain a secondary quality-such as smell, or taste, or sound, or colour, or heat-there appears no manifest absurdity in the supposition.

smoothness, to figure and motion, that we may be excused from making the application, which would only be a repetition of what hath been said. All these, by means of certain corresponding sensations of touch, are presented to the mind as real external qualities; the conception and the belief of them are invariably connected with the corresponding sensations, by an original principle of human nature. Their sensations have no name in any language; they have not only been overlooked by the vulgar, but by philosophers; or, if they have been at all taken notice of, they have been confounded with the external qualities which they suggest.

Section V.

OF EXTENSION.

It is further to be observed, that hardness and softness, roughness and smoothness, figure and motion, do all suppose extension, and cannot be conceived without it; yet, I think it must, on the other hand, be allowed that, if we had never felt any thing hard or soft, rough or smooth, figured or moved, we should never have had a conception of extension; so that, as there is good ground to believe that the notion of extension could not be prior to that of other primary qualities, so it is certain that it could not be posterior to the notion of any of them, being necessarily implied in them all.†

Extension, therefore, seems to be a quality suggested to us, by the very same sensations which suggest the other qualities above mentioned. When I grasp a ball in my hand, I perceive it at once hard, figured, and extended. The feeling is very simple, and hath not the least resemblance to any quality of body. Yet it suggests to us three primary qualities perfectly distinct from one another, as well as from the sensation which indicates them. When I move my hand along the table, the feeling is so simple that I find it difficult to distinguish it into things of different natures; yet, it immediatey suggests hardness, smoothness, extension, and motion-things

ture.

What hath been said of hardness, is so easily applicable, not only to its opposite, softness, but likewise to roughness and

On this distinction of Primary and Secondary Qualities, see" Essays on the Intellectual Powers," Essay 11., chap. 17, and Note D, at the end of the volume.-H.

the occasions required by the mind to exert the acts, of which the intuition of space is a condition. To the former it is thus a contingent: to the latter, a necessary mental possession.-H.

In this paragraph, to say nothing of others in the "Inquiry," Reid evidently excludes sight as a sense, through which the notion of extension or space, enters into the mind. In his later work, the "Es. says on the Intellectual Powers," he, however, expressly allows that function to sight and touch, and to those senses alone. See Essay II., chap, 19, p. 262, quarto edi.ion.-H.

other, and never have been able to discern that they were not only distinct things, but altogether unlike. However, if we will reason distinctly upon this subject, we ought to give names to those feelings of touch; we must accustom ourselves to attend to them, and to reflect upon them, that we may be able to disjoin them from, and to compare them with, the qualities signified or suggested by them.

The habit of doing this is not to be attained without pains and practice; and till a man hath acquired this habit, it will be impossible for him to think distinctly, or to judge right, upon this subject.

Let a man press his hand against the table-he feels it hard. But what is the meaning of this?-The meaning undoubtedly is, that he hath a certain feeling of touch, from which he concludes, without any reasoning, or comparing ideas, that there is something external really existing, whose parts stick so firmly together, that they cannot be displaced without considerable force. There is here a feeling, and a conclusion drawn from it, or some way suggested by it. In order to compare these, we must view them separately, and then consider by what tie they are connected, and wherein they resemble one another. The hardness of the table is the conclusion, the feeling is the medium by which we are led to that conclusion. Let a man attend distinctly to this medium, and to the conclusion, and he will perceive them to be as unlike as any two things in nature. The one is a sensation of the mind, which can have no existence but in a sentient being; nor can it exist one moment longer than it is felt; the other is in the table, and we conclude, without any difficulty, that it was in the table before it was felt, and continues after the feeling is over. The one implies no kind of extension, nor parts, nor cohesion; the other implies all these. Both, indeed, admit of degrees, and the feeling, beyond a certain degree, is a species of pain; but adamantine hardness does not imply the least pain.

And as the feeling hath no similitude to hardness, so neither can our reason perceive the least tie or connection between them; nor will the logician ever be able to shew a reason why we should conclude hardness from this feeling, rather than softness, or any other quality whatsoever. But, in reality, all mankind are led by their constitution to conclude hardness from this feeling.

The sensation of heat, and the sensation we have by pressing a hard body, are equally feelings; nor can we, by reasoning, draw any conclusion from the one but what may be drawn from the other: but, by our constitution, we conclude from the first an ob

scure or occult quality, of which we have only this relative conception, that it is something adapted to raise in us the sensation of heat; from the second, we conclude a quality of which we have a clear and distinct conception-to wit, the hardness-of the body.

Section VI.

OF EXTENSION.

To put this matter in another light, it may be proper to try, whether from sensation alone we can collect any notion of extension, figure, motion, and space.* I take it for granted, that a blind man hath the same notions of extension, figure, and motion, as a man that sees; that Dr Saunderson had the same notion of a cone, a cylinder, and a sphere, and of the motions and distances of the heavenly bodies, as Sir Isaac Newton.+

As sight, therefore, is not necessary for our acquiring those notions, we shall leave it out altogether in our inquiry into the first origin of them; and shall suppose a blind man, by some strange distemper, to have lost all the experience, and habits, and notions he had got by touch; not to have the least conception of the existence, figure, dimensions, or extension, either of his own body, or of any other; but to have all his knowledge of external things to acquire anew, by means of sensation, and the power of reason, which we suppose to remain entire.

We shall, first, suppose his body fixed immovably in one place, and that he can only have the feelings of touch, by the application of other bodies to it. Suppose him first to be pricked with a pin-this will, no doubt, give a smart sensation : he feels pain; but what can he infer from it? Nothing, surely, with regard to the existence or figure of a pin. He can infer nothing from this species of pain, which he may not as well infer from the gout or sciatica. Common sense may lead him to think that this pain has a cause; but whether this cause is body or spirit, extended or unextended, figured or not figured, he cannot possibly, from any principles he is supposed to have, form the least conjecture. Having had formerly no notion of body or of extension, the prick of a pin can give him

none.

Suppose, next, a body not pointed, but

Why are Extension and Space distinguished as

co-ordinate, and thus oddly sundered ?-H.

The observations of Platner, on a.person born

blind, would prove, however, that sight, not touch, is the sense by which we principally obtain our know. ledge of Figure, and our empirical knowledge of Space. Saunderson, at any rate, was not born blind, -H.

blunt, is applied to his body with a force gradually increased until it bruises him. What has he got by this, but another sensation or train of sensations, from which he is able to conclude as little as from the former ? A scirrhous tumour in any inward part of the body, by pressing upon the adjacent parts, may give the same kind of sensation as the pressure of an external body, without conveying any notion but that of pain, which, surely, hath no resemblance to extension.

Suppose, thirdly, that the body applied to him touches a larger or a lesser part of his body. Can this give him any notion of its extension or dimensions? To me it seems impossible that it should, unless he had some previous notion of the dimensions and figure of his own body, to serve him as a measure. When my two hands touch the extremities of a body, if I know them to be a foot asunder, I easily collect that the body is a foot long; and, if I know them to be five feet asunder, that it is five feet long; but, if I know not what the distance of my hands is, I cannot know the length of the object they grasp; and, if I have no previous notion of hands at all, or of distance between them, I can never get that notion by their being touched.

Suppose, again, that a body is drawn along his hands or face, while they are at rest. Can this give him any notion of space or motion ? It no doubt gives a new feeling; but how it should convey a notion of space or motion to one who had none before, I cannot conceive. The blood moves along the arteries and veins, and this motion, when violent, is felt: but I imagine no man, by this feeling, could get the conception of space or motion, if he had it not before. Such a motion may give a certain succession of feelings, as the colic may do ; but no feelings, nor any combination of feelings, can ever resemble space or motion.

Let us next suppose, that he makes some instinctive effort to move his head or his hand; but that no motion follows, either on account of external resistance, or of palsy. Can this effort convey the notion of space and motion to one who never had it before? Surely it cannot.

He

Last of all, let us suppose that he moves a limb by instinct, without having had any previous notion of space or motion. has here a new sensation, which accompanies the flexure of joints, and the swelling of muscles. But how this sensation can convey into his mind the idea of space and motion, is still altogether mysterious and unintelligible. The motions of the heart

Nay, the recent observations of Weber establish the curious fact, that the same extent will not appear the same to the touch at different parts of the body. -H.

|

and lungs are all performed by the contraction of muscles, yet give no conception of space or motion. An embryo in the womb has many such motions, and probably the feelings that accompany them, without any idea of space or motion.

Upon the whole, it appears that our philosophers have imposed upon themselves and upon us, in pretending to deduce from sensation the first origin of our notions of external existences, of space, motion, and extension, and all the primary qualities of body—that is, the qualities whereof we have the most clear and distinct conception. These qualities do not at all tally with any system of the human faculties that hath been advanced. They have no resemblance to any sensation, or to any operation of our minds; and, therefore, they cannot be ideas either of sensation or of reflection. The very conception of them is irreconcilable to the principles of all our philosophic systems of the understanding. The belief of them is no less so.

Section VII.

OF THE EXISTENCE OF A MATERIAL WORLD.

It is beyond our power to say when, or in what order, we came by our notions of these qualities. When we trace the operations of our minds as far back as memory and reflection can carry us, we find them already in possession of our imagination and belief, and quite familiar to the mind: but how they came first into its acquaintance, or what has given them so strong a hold of our belief, and what regard they deserve, are, no doubt, very important questions in the philosophy of human nature.

Shall we, with the Bishop of Cloyne, serve them with a quo warranto, and have them tried at the bar of philosophy, upon the statute of the ideal system? Indeed, in this trial they seem to have come off very pitifully; for, although they had very able counsel, learned in the law-viz., Des Cartes, Malebranche, and Locke, who said everything they could for their clients-the

That the notion of Space is a necessary condition of thought, and that, as such, it is impossible to derive it from experience, has been cogently demon. strated by Kant. But that we may not, through sense. have empirically an immediate perception of something extended, I have yet seen no valid reason to doubt. The a priori Conception does not exclude the a posteriori Perception; and this latter cannot be rejected without belying the evidence of consciousness, which assures us that we are immediately cognizant, not only of a Self but of a Not-Self, not only of mind but of matter: and matter cannot be immediately known-that is, known as existing-except as some. thing extended. In this, however, I venture a step beyond Reid and Stewart, no less than beyond Kant; though I am convinced that the philosophy of the two former tended to this conclusion, which is, in fact, that of the common sense of mankind,—H.

Bishop of Cloyne, believing them to be aiders and abetters of heresy and schism, prosecuted them with great vigour, fully answered all that had been pleaded in their defence, and silenced their ablest advocates, who seem, for half a century past, to decline the argument, and to trust to the favour of the jury rather than to the strength of their pleadings.

Thus, the wisdom of philosophy is set in opposition to the common sense of mankind. The first pretends to demonstrate, a priori, that there can be no such thing as a material world; that sun, moon, stars, and earth, vegetable and animal bodies, are, and can be nothing else, but sensations in the mind, or images of those sensations in the memory and imagination; that, like pain and joy, they can have no existence when they are not thought of. The last can conceive no otherwise of this opinion, than as a kind of metaphysical lunacy, and concludes that too much learning is apt to make men mad; and that the man who seriously entertains this belief, though in other respects he may be a very good man, as a man may be who believes that he is made of glass; yet, surely he hath a soft place in his understanding, and hath been hurt by much thinking.

This opposition betwixt philosophy and common sense, is apt to have a very unhappy influence upon the philosopher himself. He sees human nature in an odd, unamiable, and mortifying light. He considers himself, and the rest of his species, as born under a necessity of believing ten thousand absurdities and contradictions, and endowed with such a pittance of reason as is just sufficient to make this unhappy discovery: and this is all the fruit of his profound speculations. Such notions of human nature tend to slacken every nerve of the soul, to put every noble purpose and sentiment out of countenance, and spread a melancholy gloom over the whole face of things. If this is wisdom, let me be deluded with the vulgar. I find something within me that recoils against it, and inspires more reverent sentiments of the numan kind, and of the universal administration. Common Sense and Reason have both one author; that Almighty Author in all whose other works we observe a consistency, uniformity, and beauty which charm and delight the understanding: there must, therefore, be some order and consistency in the human faculties, as well as in other parts of his workmanship. A man that thinks reverently of his own kind, and esteems true wisdom and philosophy, will not be fond, nay, will be very suspicious, of such strange

• The reader will again notice this and the other instances which follow, of the inaccuracy of Reid's Janguage in his earlier work, constituting, as differ.

ent, Reason and Common Sense.-H.

and paradoxical opinions. If they are false, they disgrace philosophy; and, if they are true, they degrade the human species, and make us justly ashamed of our frame.

To what purpose is it for philosophy to decide against common sense in this or any other matter? The belief of a material world is older, and of more authority, than any principles of philosophy. It declines the tribunal of reason, and laughs at all the artillery of the logician. It retains its sovereign authority in spite of all the edicts of philosophy, and reason itself must stoop to its orders. Even those philosophers who have disowned the authority of our notions of an external material world, confess that they find themselves under a necessity of submitting to their power.

Methinks, therefore, it were better to make a virtue of necessity; and, since we cannot get rid of the vulgar notion and belief of an external world, to reconcile our reason to it as well as we can; for, if Reason should stomach and fret ever so much at this yoke, she cannot throw it off; if she will not be the servant of Common Sense, she must be her slave.

If

In order, therefore, to reconcile Reason to Common Sense in this matter, I beg leave to offer to the consideration of philosophers these two observations. First, That, in all this debate about the existence of a material world, it hath been taken for granted 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. 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; 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 sensa

See last note.-H.

we