The Scottish Philosophy [261]
natural, who maintain that we know the external thing directly; or hypothetical (cosmothetic idealists), who suppose that there is a real world not directly known. Idealists are absolute or presentative, who suppose that there is only the idea; or cosmothetic or representative (hypothetical realists) who bold that we know the external thing by a representation. The possible forms of the representative hypothesis are three: (1) The representative object not a modification of mind, but an extra-mental object, physical or hyperphysical; (2) The representative object a modification of mind, dependent for its apprehension, but not for its existence, on an act of consciousness, say an idea in the mind, as was held apparently by Locke; (3) The representative object a modification of mind, non-existent out of consciousness, the idea and its perception only different relations of an act (state) really identical; the view taken by Arnauld and Brown. The distinctions thus drawn are of great importance, and should be kept steadily in view in judging of theories. But his divisions do not embrace all cases. Dr. Brown does not bold by the ideal, but the causal or inferential, theory; and Hamilton has missed the mark in his criticism of him.
I am inclined to agree with him that our original perceptions are probably of our organism, or of objects in immediate contact with it. This doctrine seems to have been expounded {433} simultaneously by Hamilton; by Saisset, the French metaphysician; and by John Muller, the physiologist. On one small point I would differ from Hamilton. Our original perceptions through the eye do not seem to me to be points of light, but of a colored surface affecting our organism, but at what distance we cannot say till experience comes to our aid. But the doctrine identified with his name is that of immediate perception. He intended to take the same view as Reid did, and, when he began to edit Reid's works, he thought that their opinions were the same. But, as he advances, he sees that they differ; and he ends by doubting whether Reid was after all a realist. Reid's doctrine is, that there is first an organic affection; then a sensation in the mind; and, thirdly, a perception suggested by an unreasoning and instinctive process. Hamilton's doctrine is, that, following the organic affection, there is simultaneously a sensation and perception, the one being strong as the other is weak, and; that is, when the sensation is lively the perception is faint, and when the perception is prominent the impression is feeble. Both, however, agree in the main point, that the process is intuitive and that there is no reasoning involved. Hamilton's doctrine is specially that of perception; that is, of perception without a medium.
It is objected to Hamilton's theory, that he overlooks the numerous intermediate processes revealed by physiology. In vision there are the rays of light; the reflection and refraction of them, the picture on the retina, an action along the optic nerve to the seat of sensation, an action thence we know not how to the brain, an action in the cells which constitute the gray matter surrounding the brain, and then, or perhaps not even then, but only after some farther steps, the perception of the object, say a tree, from which the rays of light come. How it is asked can perception be immediate, when all these media are evidently implied? To this the followers of Hamilton might reply, that he never thought of disputing the existence of steps between the external object and the percipient mind, which, when it comes into exercise, contemplates the tree, and not an image or representation of it in the mind, in the body or out of the body. But the objection may now take a somewhat different form. It may be urged that, after all, we do not see the tree, {434} and it will be asked, What do we perceive intuitively? Certainly not the brain cells, or the influence transmitted to them, or the action of the sensorium, or even the image on the retina, or the coats and humors of the eye,
I am inclined to agree with him that our original perceptions are probably of our organism, or of objects in immediate contact with it. This doctrine seems to have been expounded {433} simultaneously by Hamilton; by Saisset, the French metaphysician; and by John Muller, the physiologist. On one small point I would differ from Hamilton. Our original perceptions through the eye do not seem to me to be points of light, but of a colored surface affecting our organism, but at what distance we cannot say till experience comes to our aid. But the doctrine identified with his name is that of immediate perception. He intended to take the same view as Reid did, and, when he began to edit Reid's works, he thought that their opinions were the same. But, as he advances, he sees that they differ; and he ends by doubting whether Reid was after all a realist. Reid's doctrine is, that there is first an organic affection; then a sensation in the mind; and, thirdly, a perception suggested by an unreasoning and instinctive process. Hamilton's doctrine is, that, following the organic affection, there is simultaneously a sensation and perception, the one being strong as the other is weak, and
It is objected to Hamilton's theory, that he overlooks the numerous intermediate processes revealed by physiology. In vision there are the rays of light; the reflection and refraction of them, the picture on the retina, an action along the optic nerve to the seat of sensation, an action thence we know not how to the brain, an action in the cells which constitute the gray matter surrounding the brain, and then, or perhaps not even then, but only after some farther steps, the perception of the object, say a tree, from which the rays of light come. How it is asked can perception be immediate, when all these media are evidently implied? To this the followers of Hamilton might reply, that he never thought of disputing the existence of steps between the external object and the percipient mind, which, when it comes into exercise, contemplates the tree, and not an image or representation of it in the mind, in the body or out of the body. But the objection may now take a somewhat different form. It may be urged that, after all, we do not see the tree, {434} and it will be asked, What do we perceive intuitively? Certainly not the brain cells, or the influence transmitted to them, or the action of the sensorium, or even the image on the retina, or the coats and humors of the eye,