# Catholic Encyclopedia (1913)/Philosophy of Common Sense

From volume 4 of the work.
The term common sense designates (1) a special faculty, the sensus communis of the Aristotelean and Scholastic philosophy; (2) the sum of original principles found in all normal minds; (3) the ability to judge and reason in accordance with those principles (recta ratio, good sense). It is the second of these meanings that is implied in the philosophy of common sense — a meaning well expressed by Fenelon when he identifies common sense with "those general ideas or notions which I can neither contradict nor examine, but according to which I examine and decide on everything; so that I smile rather than answer whenever anything is proposed to me that obviously runs counter to those unchangeable ideas" (De l'existence de Dieu, p. XXII, c. ii). The philosophy of common sense sometimes called Scottish philosophy from the nationality of its exponents (though not all Scottish philosophers were adherents of the Common Sense School), represents one phase of the reaction against the idealism of Berkeley and Hume which in Germany was represented by Kant. The doctrine of ideas, which Locke had adopted from Descartes, had been made use of by Berkeley as the foundation of his theory of pure idealism, which resolved the external world into ideas, without external reality, but directly impressed on the mind by Divine power. Hume, on the other hand, had contended that there was no ground for assuming the existence of any mental substance as the subjective recipient of impressions and ideas, all that we know of mind being a succession of states produced by experience. Thus, between the two, both subject and object disappeared, and philosophy ended in mere scepticism.
Thomas Reid (1710-1796), whose dissent from Locke's doctrine of ideas had been to some extent anticipated by Francis Hutcheson (1694-1746), set out to vindicate the common sense, or natural judgement, of mankind, by which the real existence of both subject and object is held to be directly known (natural realism). He argued that if it cannot be proved that there is any real external world or continuously existing mind, the true conclusion is not that these have no existence or are unknowable, but that our consciousness of them is an ultimate fact, which neither needs nor is capable of proof, but is itself the ground of all proof. "All knowledge and all science must be built upon principles that are self-evident; and of such principles every man who has common sense is a competent judge" (Works, ed. 1863, p. 422). Dugald Stewart (1753-1828), who followed Reid's method without serious modification, was more precise, and gave greater prominence than Reid to his doctrine of "suggestion", or the association of ideas. Dr. Thomas Brook (1778-1820), while accepting Reid's main principal, carried the analysis of the phenomena of perception further than either Reid or Stewart, resolving some of their first principles into elements of experience, particularly in his treatment of the notion of causality. Sir James Mackintosh (1765-1832) adopted the principles of common sense, but accepted the utilitarian criterion of morality, held by the school of Hartly, and applied the analytic method to the moral faculty which Reid had taken to be "an original power in man". Sir William Hamilton (1788-1856) illustrated the prin- ciple of common sense with wider learning and greater philosophical acumen than any of his predecessors. He was much influenced by Kant, and he introduced into his system distinctions which the Common Sense School had not recognized. While professing himself a natural realist, he held a somewhat extreme doctrine of the relativity of knowledge. His comments on Reid indicate many ambiguities and inaccuracies on the part of that author. James Oswald (l727-1793) made use of Reid's principles in support of religious belief, and James Beattie (1735-1803) in defence of the existence of a moral faculty.
The common sense philosophy, adopting the Baconian method of "interrogation", or analysis, rejects, as contrary to the universal convictions of mankind, the notion of ideas as a tertium quid intervening between the object perceived and the perceiving subject. All knowledge comes by way of sensation; and the reality of the external object is implied in sensation, together with the metaphysical principle of the existence of bodily and mental substance, of causality, and of design and intelligence in causation. What sensation is in itself it is impossible to say; it is an ultimate fact, and cannot be described or defined. But sensations are clearly not images or ideas of the objects which cause them; there is no resemblance between the pain of a wound and the point of a sword. Reid and his successors insist on the distinction between primary and secondary qualities, the former (extension, figure, hardness, etc.) being "suggested" by sensations as essentially belonging to the object perceived, and the latter (as colour, taste, smell, etc.) being no more than sensations in the subject arising from qualities of the object which are only accidental or contingent. Hamilton, however, subdivides secondary qualities into secondary and secundo-primary, a distinction now generally considered to be ill-founded. The mental powers are divided into intellectual and active, a distinction corresponding to the peripatetic classification of cognitive and appetitive. All cognition has thus an intellectual element, and takes place by way of suggestion, or association (a theory in which Reid was anticipated by Hutcheson). In cognition the mind is partly active and partly passive; the notion that it is a mere receptacle for ideas is rejected. Consciousness is regarded by Reid as a separate faculty, somewhat resembling the scholastic sensus communis; Brown and Hamilton dissent from this view, holding "consciousness" to be merely a general expression for the fundamental condition of all mental activity. The idea of causality, which implies the universal necessity of causation, cannot be educed from experience, since necessity (as opposed to mere invariableness) cannot be known by experience; it is therefore an original principle in the mind. In like manner, the will is known immediately as free; its freedom is not susceptible of proof but is intuitively recognized; and it is from the consciousness of will-power in ourselves that we derive our notion of causation. Brown, however, while accepting Reid's intuitional view of the idea of causality, inclines towards Hume in his definition of causation as no more than invariable sequence; he also differs from Reid in making will a modification of desire or appetite. The belief in the uniformity of nature, on which all scientific discovery is based, is held by Reid to be an original principle in the mind. Conscience, or the moral sense, is taken to be an original faculty by the Common Sense School in general, with the exception of Mackintosh, who derives the so-called faculty in great measure from the influence of social experience upon the will.
The psychological analysis of this school is valuable; but its main principle has been considerably weakened by contact with Kantian criticism and the evolutionist doctrine, and with Hamilton lost much of its polemical effectiveness. "The philosophy of Common Sense, devised by Reid as a safeguard against Scepticism and Idealism, was so transmuted by Hamilton as to lead back again to the conclusion that nothing can be known, and consequently that nothing can be affirmed or denied, beyond the fleeting phenomena of consciousness" (Laurie, Scottish Philosophy, p. 291). In France, Royer-Collard (1763-1845) introduced the principles of the Scottish School; Jouffroy (1796-1842) translated the works of Reid; and Cousin (1792-1867) in his "Philosophie ecossaise" praised Reid's philosophy in the highest terms. It may be safely said that the materialistic tendency of French speculation was checked by the influences derived from the philosophy of common sense.
Hutchenson, Essay on the Passions and Affections (London, 1728). Idem, Metaphysical Synopsis (London, 1742). Idem, System of Moral Phil. (Glasgow, 1755). Reid, Works, with preface, notes, and dissertation by Hamilton (Edinburgh, 1846); new ed. by Mansel (1863). Buffier, Premieres Verites (tr. London, 1781), "with a detection of the plagiarism, concealment, and ingratitude of Drs. Reid, Beattie, and Oswald". Jouffroy, Oeuvres completes de Reid (Paris, 1829). Oswald, Appeal to Common Sense (Edinburgh, 1768). Beattie, Essay on Truth (Aberdeen, 1770). Idem, Elements of Moral Science (1790). Priestly, Examination of Reid, etc. (London, 1774). Stewart, Complete Works (Cambridge, Mass., 1829-31); ed. with additions and memoir by Sir W. Hamilton and completed by Veitch (Edinburgh, 1858). Brown, Inquiry into Relation of Cause and Effect (Edinburgh, 1804). Idem, Lectures on the Phil. of the Human Mind (Edinburgh, 1820). Mackintosh, On the Progress of Ethical Philosophy in Encyc. Brit. (1830); ed. with preface by Whewell (Philadelphia, 1832). Idem, two papers in Edinburgh Review, XXVII, XXXVI. Hamilton, Lectures, ed. Mansel and Veitch (London, Edinburgh, and Boston, 1860). Idem, Essays in Edinburgh Review (1829-30-32). Idem, Metaphysics, ed. Bowen (Cambridge, Mass., 1870); see Mill, Exam. of Hamilton's Philosophy (London, 1865). McCosh, Scottish Philosophy (London, 1875). Seth (A. S. Pringle-Pattison), Scottish Philosophy (Edinburgh and London, 1885 and 1900). Ferrier, Reid and the Philosophy of Common Sense (1847) in Ferrier's Works (Edinburgh and London, 1883), III, 407; see also Maher, Psychology (London, 1903), 33, 49, 102 sqq. James, Pragmatism (London and New York, 1907), lect v. Laurie, Scottish Philosophy in its National Development (London and Glasgow, 1902).
A.B. SHARPE