follows the course of the notion of the form of it. substance it resists him; hard substance, it yields to his pressure, and thus gets the idea of hard and soft. He touches something cold or warm, and thus is furnished with the information that some external objects are warm and some cold. edges, till he obtains some He lays his hand on a soft but he finds that, unlike the Meanwhile, he is learning the use of his eyes, and is wonderfully aided by them in his discoveries. He finds out, in turning his eyes in different directions, that he changes the sensations he receives from them: that by fixing them in one direction, he prolongs a sensation; that when he turns them away the sensation ceases; when he brings them back to the same position, the sensation is renewed. Having mastered the achievement of directing his eyes and his hands to the same point, he begins to connect his sensations of sight with those of touch. He finds that objects which have different forms, as ascertained by handling them, have also different appearances; that when he holds anything in his hand and brings it near his eye, it looks large; and that when he stretches his hand from his eye, it looks small; that when he turns the object in his hand in one direction, it has one appearance, and when he turns it in another direction the appearance altogether changes; and thus, by incessant trials, he gradually learns to distinguish the various notices given by the sense of sight of the forms, positions, and distances of the various objects that come within the reach of his investigations. away As his powers of motion extend, his knowledge of distances increases. He sees a glittering object when his eyes look in a certain direction; he stretches out his hand in the same direction, but cannot reach it; he stretches his whole body towards it, and does reach it. On a similar occasion be continues to move his whole body towards it, and, after an arduous struggle, gets hold of it. He has now discovered an important secret, and when he sees such an object which he finds he cannot reach, he appeals for help, and insists on being moved towards it, or on its being brought nearer to him. His eyes are thus gradually acquiring facility in judging of the distance of objects. As he acquires the power of moving himself along the floor, his sensations of touch and sight become more perfectly corrected to one another; till a glance of any known object in its various distances, positions, lights, and shades, instantly intimates to him what it is, how far off it is, in what direction, and in what position it is. His other senses also come to aid him in his inquiries. His mother, or nurse, becomes known to him, not only by sight and touch, but also by the sound of her voice and her smell; and he gradually learns to recognise her by the eye, at various distances, and in various attitudes and positions. When the mind is fully possessed with the belief that the sensations of sight and touch come from without, it learns to apply the same principle to sensations from the other senses, and to become equally persuaded that sounds and smells come from without also: and which persuasion it finds, in ordinary cases, confirmed by fact. In regard to tastes, the manner in which we receive them, and the sense of touch that accompanies them, constrain us to ascribe them to external objects, as soon as we know that there are external objects. We at length become so fully possessed with the persuasion that all our sensations are caused by external objects, that we become prone to carry the persuasion beyond the truth; and when we experience a sensation of ringing in the ears by some derangement of the organ itself, we ascribe it to a ringing of bells; or if, from disease in the brain, visual sensations are recalled with unusual vivacity, as in delirium tremens, the patient imagines that he is looking at external objects. The reader is not to imagine that we have attempted to trace the exact process, in order, by which the mind of every infant becomes acquainted with external objects; for that must be as various as the various circumstances in which every infant is placed. In some the process may be more slow, in others more rapid. The order of discovery may be different in different minds; but in all there must be processes such as we have described. And to one accustomed to observe infants, the effect of these processes may often be detected. The long, atten tive gaze, followed by a smile or chuckle of delight, indicates some pleasant discovery, or the consciousness of some new achievement. The eye following a candle, or other bright object, losing it by looking in another direction, and intimating the loss by a whimper or a tear, recovering it again by looking in the proper direction, and hailing it with a laugh of complacency; the eyes intently looking in a particular direction, and the hand stretched out in the same direction, and touching or laying hold on some object that had arrested its attention; the careful examination that it may sometimes be seen making of its own fingers, holding them up, turning them round, shutting, opening them, with its eyes all the while intently fixed on them, are all indications of the mind vigorously engaged in acquiring the elements of knowledge. The cognition of the external world thus obtained by means of sensation and muscular effort we call PERCEPTION, or the perceiving of the existence and qualities of external objects. Much subtlety has been expended on this subject, which we do not feel ourselves called upon to detail. · Some of the ancients, as we have already mentioned, imagined that we perceived external objects by means of species or ideas, which emanated from all objects, entered the mind by the senses, and so produced perception. More modern metaphysicians then inferred that if we perceived nothing but what was in the mind, we had no evidence of the existence of anything but the ideas in the mind, and that we had no reason to believe there was any external world, but rather the contrary. Then came David Hume, and irresistibly proved that if this were the state of matters, there is no evidence for the existence of anything, even the mind itself, and its ideas. These startling conclusions drew the attention of Dr. Thomas Reid, and others after him, to the whole theory, of perception being effected by means of species or ideas, and led them to assert that our inferring the existence and qualities of external objects from the sensations of touch was intuitive-a part of our constitution of which we could not divest ourselves, that it was anterior to all reasoning, and therefore could never be proved by reasoning. Dr. Brown, the successor of Dugald Stewart, has traced the discovery of external objects to the sense of touch combined with conscious muscular movement; and the inference of the existence of external things from these two phenomena of the mind, namely, tactile sensations, combined with the conscious movement of the limbs in various directions -is so direct and so necessary to us, that if any infant should not make these inferences, and so should not become acquainted with external objects, it would remain an idiot. It seems to be a sufficient penalty on the rejection of an external world, or the entertaining of any serious practical doubts of its existence, that any man who should do so, would, in his search after philosophy, deprive himself of his reason, and effectually qualify himself for a lunatic asylum. CHAPTER II. NOTION OF SELF, OR PERSONAL IDENTITY. WHEN the mind, according to our first hypothesis, was, in consequence of its want of power to move any part of the body, destitute of the means of discovering the existence of anything external to itself, it could form no conception of any being other than itself. Its own sensations, and its ruminations of them, with the pains and pleasures, the hopes and fears, the joys and sorrows, the pleasant surprises and the disappointments of which it was the subject, constituted the whole universe to it. But when, by the power of moving the body, combined with the sense of touch, it acquired the knowledge of the existence and qualities of beings external to itself, it necessarily acquired, at the same time, the notion of myself, or of its own personal identity. Personal identity may either be regarded as the distinction of self from other beings at any given moment, or the identity of self at different periods of existence; or, in other words, personal identity as distinguished from other beings without regard to time, and personal identity with regard to continued duration. There is also another distinction that requires to be attended to, -namely, on the one hand my personal identity as it is apprehended by others, or the personal identity of others. as apprehended by me, and on the other, personal identity as it is apprehended by the person himself who apprehends it, that is, the notion of thyself or himself, and the notion of myself. -- With respect to my own identification of myself from others at the present moment, it depends on the body, through which exclusively my mind is affected, and over which my mind has direct power. Every sensitive part of my body, and every member of my body over which |