Aberdeen, Lord Karnes, Dr. James Gregory, and others, on interesting questions in physics and metaphysics, are contained in Sir William Hamilton's collected edition of the works of Reid—a collection which, with the editor's notes and dissertations, is probably the most valuable contribution which British intellect has yet made to the discussions of mental philosophy. The interval between the first and the last of Reid's philosophical works amounts to no less than forty years, although he had attained to the age of thirty-eight before he ventured to appear as an author. Mathematical problems, the intellectual exercise of his youth, were the amusement of his wise and benignant old age, which was closed at Glasgow on the 7th of October, 1796, in his eighty-seventh year.
The metaphysical philosophy of Reid was a moderate and sober recoil, on the part of the British philosophy originated by Locke, against the sceptical paralysis of all philosophy promoted by David Hume—the most subtile intellectualist bred in Locke's school. In its chronological development, as well as in its general aim, it coincides with the professedly antisceptical movement which Kant originated in Germany. The same decade which gave birth in Glasgow to the "Essays" on the Intellectual and the Active Powers, witnessed the publication of the Critiques of Pure and Practical Reason by the philosopher of Königsberg. And the "Common Sense" of Reid corresponds to the Reason, pure and practical, of Kant; although the Scottish metaphysician, overlooking the more subtile analysis of the pure or speculative Reason, describes and employs, under the name of Common Sense, those feelings and tendencies which sway the conduct of the mass of mankind. But the spirit and method, and also the central problem, of the Scottish and German leaders of the reactionary conservative philosophy of last century, were in many ways different. Reid was deeply imbued with the tentative spirit of experimental research, natural to the island of Bacon, Newton, and Locke. He aimed at utility more than speculative refinement, of which he was constitutionally incapable. Kant, charged with the idealizing rationalism natural to his countrymen, and to the school of Leibnitz, constructs a more lofty and ingeniously adjusted edifice, which brings within his mental vision problems of which Reid had no conception. The starting point of Reid was the current scepticism, as he regarded it, about the world given in the external senses; the starting point of Kant was Hume's sceptical inferences in regard to causation. The regulative conception of Kant's speculative philosophy is accordingly the theory of causation; the basis of the philosophy of Reid is the Fact of External Perception. The key to Reid's whole philosophy may be given in his own words. "The doctrine of ideas," he tells us (writing in 1785), "I once believed so firmly as to embrace the whole of Berkeley's system in consequence of it; till, finding other consequences follow from it, which gave me more uneasiness than the want of a material world, it came into my mind, more than forty years ago, to put the question to myself—'What evidence have I for this doctrine, that all the objects of my knowledge are ideas in my own mind?' From that time to the present I have been candidly and impartially, as I think, seeking for the evidence of this principle, but can find none, excepting the authority of philosophers."—(Essays on Intellectual Powers, Essay ii. ch. 10.) "The merit of what you are pleased to call my philosophy," says Reid, in a letter to Dr. Gregory, "lies, I think, chiefly in having called in question the common theory of ideas or images of things in the mind being the only objects of thought—a theory founded on natural prejudices, and so universally received as to be interwoven with the structure of language. Yet were I to give you a detail of what led me to call in question this theory, after I had long held it as self-evident and unquestionable, you would think as I do, that there was much of chance in the matter. The discovery was the birth of time, not of genius; and Berkeley and Hume did more to bring it to light than the man that hit upon it. I think there is hardly anything that can be called mine in the philosophy of the mind, which does not follow with ease from the detection of this prejudice."
How is this? Why should scepticism emanate from this "prejudice," and in what way is scepticism deprived of its power by the "detection" of the prejudice? What body of metaphysical doctrine, different from the view of the understanding given by Des Cartes, Malebranche, Locke, Berkeley, and Hume has Reid derived from his "discovery" of the unsoundness of the philosophical hypothesis of ideas? A sufficient answer to these questions should afford us a full insight into Reid's philosophy. The professed result of that philosophy is to uncover, as it were, the genuine or common reason of man, through an attentive study of the natural operations of the human mind, and to substitute what is thus uncovered for the artificial hypothesis of ideas (with its latent scepticism) by which it had been overlaid. It is a vindication of our spontaneous faith in perceived reality, in the form of a return to that faith through reflection. It was in its account of perception through the senses that, according to Reid, our spontaneous mental experience was primarily overlaid by the philosophical hypothesis of a sense-perception only of ideas which have no existence at all out of the perceiving mind. It is our genuine sense-perception, accordingly, that Reid first of all sets himself to recover by reflection and describe. Having expelled the ideal illusion from that quarter, he hopes, with comparative ease, to track out the element of reality in every other department of consciousness, and to exhibit in their native strength the practical principles which constitute the unvitiated common reason of mankind. Reid thinks he has found, by patient study of his own mental operations, that, in external sense, we are all, and know ourselves to be, in immediate or conscious intercourse with real external things, and not merely with transient images or representations of them; that in smell, taste, hearing, touch, and seeing, we have not merely special orders of sensations, dependent on our consciousness of them, but also in each a perception of something that may exist when it is not smelled, tasted, heard, touched, or seen. No sufficient philosophical reasonings, he is certain, have been, or can be, offered to disturb this finding of an experience common to men. This experience being accepted in its original integrity, we have, within the range of our immediate perception, without any help from reasoning, a world that is real and not merely ideal—that exists independently of our consciousness or perception of it—that does not need the help of a representative faculty to bring it within the range of our perception, while our perception of it supplies materials to the representative faculty in its own legitimate sphere. This analysis of external sense, professedly in the light of the common reason of men, is the type of Reid's teaching, in which he applies to the mental operations generally the method which enabled him to detect the element of external reality in the operations of sense. He discards as mere hypothesis the immediate universe of the philosophers, made up of ideas, and which exists only in the mind that perceives it. He traces out the indications of a real, material and moral universe, which exists independently of the conscious mind, but is partially revealed to us in and through the operations of our various faculties—i.e., in our spontaneous or common-sense beliefs, concerning the present, the past, and the future—indications which we are prepared to receive as fundamental facts in philosophy, when we substitute submission to our mental experience in the place of hypothetical systems, reared on the artificial and unsubstantial foundation of ideas which exist only in the mind that perceives them.
It may well be doubted whether, in his theory of external perception, Reid fairly hit the blot in the scepticism of last century, and still more whether his method and its results are the adequate corrective of the scepticism of this age. The philosophy which imposes upon all thinking men, as a preliminary duty, the production of inductive or deductive proof of a world of real things, resembling a world of merely transient ideas or representations given to us in sense, and which subsides into scepticism when this proof cannot be produced, is, it may be granted, hollow and unsound. And, so far as Reid corrects this assumption, and accepts the real as already given in external sense, he has served philosophy well. He has brought men back from the abstractions of philosophy to the realities of life, removing an injurious excrescence, and simplifying speculation and physical science. But his extreme reaction against the imaginary consequences of Berkeleyism, has perhaps carried him to an extreme in the opposite direction. The aim of Reid and Berkeley was in fact the same, viz., a restoration of philosophical belief, by the rejection of the hypothesis of a representative knowledge in sense. They differ in their account of what the real and ultimate thing is which is given in sense. Is it, or is it not, ideal, i.e., dependent on the mind that perceives it? Are the "real things" of sense as transient as the consciousness of them? If a critical experience of our sense-consciousness determines that they are, or at least that for ought we can tell they
