REID, THOMAS. - English philosopher, born on 25 April 1710 at Strachan, near Aberdeen, where he was professor at the University from 1752 to 1764. In that year he succeeded A. Smith in the chair of moral philosophy at the University of Glasgow, where he died on 7 October 1796.
His first important work appeared in 1763: *An inquiry into the human mind on the principles of common sense* (London). Among his other works are the *Essays on the intellectual powers of man* (Edinburgh 1785) and the *Essays on the active powers of man* (ibid. 1889). The philosophy of “common sense” (v.) or of the “Scottish School,” of which Reid is the leading figure, exerted a European influence, especially in France (Jouffroy, Cousin, Maine de Biran, etc.), in Italy (Galluppi, Rosmini, etc.), in Spain (Balmes), and, of course, in England. For almost the first half of the 19th century, Reid’s name was linked with that of Kant in the critique of the empiricism (v.) of Hume and in the solution of the problems of knowledge and the origin of ideas in relation to rationalism (v.) and the empiricism of the 17th and 18th centuries.
The method of observation and analysis, whose limit is experience, is typical of Reid and his school: to know the mind, for him, is to observe and analyze the various faculties and the constitutive principles of man as an intelligent, active, social, and moral being, respecting the insurmountable limits of phenomena and renouncing any explanation of their origin (metaphysical agnosticism). Sensation (v.) and perception (v.) are the primitive acts of human knowledge, through which we know the secondary and primary qualities (both objective) of things. The immediate object of our mind is not “ideas,” but the things themselves. Sensation “attests the existence of the thing and of a quality inherent in it, a faculty of thinking and feeling, and a permanent being or spirit in which this faculty resides” (*Inquiry*, ch. 2, sect. 7). To posit between the perceived objects and the perceiving subject the intermediary of “ideas” is to be unable to avoid the skeptical consequences of Berkeley’s (v.) idealism and Hume’s (v.) phenomenism, i.e., to deny the reality of things, spiritual substance, the validity of the principle of causality, etc. Certainly, we do not know what material and spiritual substance are, nor can we demonstrate the existence of things and their qualities, but we know that they are not ideas or subjective impressions. In short, perception has an irresistible and immediate evidence (v.) that gives rise to an invincible belief (v.) that the perceiving subject exists and that the perceived things exist. All reasoning (v.) is founded on it, while it is independent of all reasoning. It is an innate question that, if it explains nothing, makes us believe in everything and gives man confidence. It is not common sense that must be unified with philosophy, but philosophy with common sense. The most immediate conclusions that reason draws from perception form common sense or that body of data by which men govern themselves in the ordinary affairs of life; the more remote conclusions form science. Science and common sense are so linked that we cannot precisely say where the one ends and the other begins. Our knowledge of nature “may be compared to a tree that has its root, its trunk, and its branches. Perception is the root, common sense the trunk, and science the branches” (*Inquiry*, ch. 6, sect. 20). In short, for Reid, the reality of things and spirits is the result of an instinct (v.) or primitive belief.
Thus the philosopher believed he had resolved, against empiricism, the problem of the objectivity of knowledge and of the real. This problem, which is the same as Kant’s in the face of Hume, often led, especially in the 19th century, the Scot to be compared with the philosopher of Königsberg. The distance, however, is enormous: Reid remains within the bounds of empiricism without managing to transcend it, ignores Kant’s concept of “critique,” and his “belief” or “instinct” is something quite different from Kant’s *a priori*. As Rosmini rightly observed (*Nuovo saggio*, II, Rome 1830, p. 245), the objectivity of knowledge cannot be founded on instinct: “common sense, authoritative to attest such a fact (the existence of an a priori cognition), is unable, however, to give any explanation of it.”
Reid deserves credit for having shown that perception is not merely representative in character and for having vindicated the principle of the activity of consciousness against the principle of passivity, characteristic of the empiricist psychology of his time and of Condillac.