The Cambridge History of English and American Literature in 18 Volumes (1907–21).
Volume X. The Age of Johnson.
§ 22. The Principles of “Common Sense”
Reid’s Inquiry into the Human Mind on the Principles of Common Sense was published in 1764; shortly afterwards, he removed to Glasgow, to fill the chair vacated by Adam Smith. His later and more elaborate works—Essays on the Intellectual Powers of Man and Essays on the Active Powers of Man—appeared in 1785 and 1788 respectively. In his philosophical work, Reid has the great merit of going to the root of the matter, and he is perfectly fair-minded in his criticism. He admits the validity of Hume’s reasonings; he does not appeal to the vulgar against his conclusions; but he follows the argument back to its premises and tests the truth of these premises. This is his chief claim to originality. He finds that the sceptical results of Hume are legitimate inferences from “the ideal theory” which Locke took over from Descartes, and he puts to himself the question, “what evidence have I for this doctrine, that all the objects of my knowledge are ideas in my own mind?” He points out (what is undoubtedly true) that neither Locke nor Berkeley nor Hume produced any evidence for the assumption. They started with the view that the immediate object of knowledge is something in the mind called ideas; and they were consequently unable to prove the existence of anything outside the mind or even of mind itself. “Ideas,” says Reid, “seem to have something in their nature unfriendly to other existences.” He solves the difficulty by denying the existence of ideas. There are no such “images of external things” in the mind, but sensation is accompanied by an act of perception, and the object of perception is the real external thing.
Hume had said that his difficulties would vanish if our perceptions inhered in something simple and individual, or if the mind perceived some real connection among them; and Reid proposes a positive theory of knowledge which will give the required assurance on this point. Every sensation is accompanied by a “natural and original judgment” which refers the sensation to mind as its act. We do not need, first of all, to get the two things “mind” and “sensation” and then to connect them; “one of the related things—to wit sensation—suggests to us both the correlate and the relation.” Reid’s terminology is not happy. The word “suggests” is badly chosen, though he distinguishes this “natural suggestion” from the suggestion which is the result of experience and habit. And his term “common sense” has given rise to more serious misunderstandings, for which he is by no means blameless. Even his doctrine of immediate perception is far from clear. But, if we read him sympathetically, we may see that he had hold of a truth of fundamental importance. The isolated impressions or ideas with which Locke and Hume began are fictions; they do not correspond to anything real in experience. The simplest portion of our experience is not separate from its context in this way; it implies a reference to mind and to an objective order, and thus involves the relations which Reid ascribed to “natural suggestion” or “common sense.”