Common Sense

COMMON SENSE. - The expression has two principal meanings in philosophy, one psychological, the other epistemological. In psychology, common sense is the internal sense that carries out the unification and discrimination of external sensations and of their objects. In epistemology, in the principal historical acceptation (Reid and his school), it is the original and universal faculty of the human spirit to apprehend and formulate, prior to philosophical reflection, necessary or evident truths, both of fact and of principle. From the historical epistemological meaning there have derived parallel acceptations in current use: common sense as the complex of the fundamental principles or truths of reason; and common sense as the natural faculty, common to every normal man, of sound theoretical-practical judgment.

I. PSYCHOLOGY

The theory of common sense as the central faculty of sensibility received its definite formulation only in medieval Scholasticism: there it is understood as the first of the internal senses, which brings about, from both the subjective and the objective point of view, the unity of the various sensations: «sensus communis est quaedam facultas ad quam terminantur immutationes omnium sensuum» (St. Thomas, In II De an., lect. 13, n. 390; cf. Sum. Theol., 1ª, q. 78, a. 4 ad 1). Common sense therefore functions, within the sphere of sensibility, as the synthetic principle, in the unity of consciousness, of the manifold data of the sensations and at the same time of the sensitive functions themselves, «a quo etiam percipiantur actiones sensuum, sicut cum aliquis videt se videre» (ibid., ad 2; cf. In III De an., lect. 3). In the Aristotelian texts, on the other hand, the theory of common sense was not free from uncertainties. Basing themselves on a sentence of the De an., III, 1, 425 a 27: «of the (sensible) common objects we already have a common sensation» (τῶν δὲ κοινῶν ἤδη ἔχομεν αἴσθησιν κοινήν), Albert the Great and, recently, Zeller, Baeumker, Ross, Cassirer, De Corte held that in Aristotle common sense is the perceptive faculty of the common sensibles (dimension, figure, movement, etc.; Sertillanges (St Thomas d'Aquin, II, 4th ed., Paris 1925) and others attributed the same doctrine to St. Thomas, but on the basis of a text of the opuscule De potentiis animae which is not authentic). Against the exegesis of Albert the Great and of Zeller stand Trendelenburg, Brentano, Waddington (cf. the careful exposition and discussion in C. Fabro, Percezione e pensiero, Milan 1941, p. 60 ff.: the Thomistic interpretation is there demonstrated - besides by the De somno et vig., 2, 455 a 12, where the expression σπανὴ δύναμις seems to have the same meaning as the «sensus communis» of St. Thomas - by the fundamental Aristotelian principle that the common sensibles are the object «per se» of several senses and not of a sixth sense). The medieval meaning of common sense was already present in St. Augustine, who in the De lib. arb., II, ch. 3 speaks of the «sensus interior» which «omnibus [sensibus externis] communiter praeest».

Later (Campanella, the Suárezian school, Mercier, Fröbes, etc.) the existence of common sense as a special faculty, distinct from the individual external senses, was contested, inasmuch as it was held that the awareness of seeing, hearing, etc., as an immediacy of consciousness is a modality inherent in the sensitive act itself, and that where it becomes reflective consciousness it belongs to the higher spiritual functions. Already Aristotle seems to affirm that every sense perceives its own act (De an., II, 425 b 15; cf. Met., XI, 9, 1074 b 35: intellect and sense can, incidentally, ἐν παρέργῳ, apprehend themselves). In modern psychology it is admitted that the synthetic unity of the various sensitive functions finds its reason in the fundamental unity of consciousness and in the centrality of the physiological processes that condition it. With common sense in the medieval meaning, however, the «cenesthesia» of modern terminology is not to be confused, which rather indicates the fundamental tactile sensibility by which one has awareness of one's own body and of its functions and general biological conditions.

II. GNOSEOLOGY

In the epistemological sense, common sense had fundamental importance in Th. Reid (v.) and his school. For Reid, who opposed Humean empiricism and Berkeleyan immaterialism, the fundamental principles of all reasoning and science are in a certain sense innate to the mind; and they are connected with perception, which is not the apprehension of "ideas" (against Berkeley), but intuitive knowing and the immediate presence of the object: "The most immediate conclusions that reason draws from perception form common sense, the most remote form science" (Inquiry, ch. 6, sec. 20). Common sense is therefore the essential capacity of the spirit, anterior to its reflective-scientific moment, to formulate universal and necessary propositions, and thus as it were the very principle of theoretical truth. Its maxims are those that prudent men follow in practice and in life and at the same time the original principles according to which the true is distinguished from the false, without which certainty is not possible. It stands at the foundation of the universal consent (v.) of every human consciousness regarding the first theoretical-practical truths. This doctrine, whose beginnings can be traced in the σπανή δύναις of the Stoics (the theme was emphasized by Cicero: cf. De nat. deor., I, 17 and De orat., I, 3; De leg., I, 10), had already found a partially analogous expression in Shaftesbury's (v.) "taste" or moral and aesthetic "sense," and was developed by the continuators of the Scottish school (J. Oswald, Appeal to common sense in behalf to religion [1766]; D. Stewart, Elements of the philosophy of human mind [1792]; Th. Brown, Lectures on the philosophy of human mind [1920]; A. Fergusson; later, with the insertion of contrasting Kantian motifs, W. Hamilton); opposition to it, on the other hand, constitutes one of the fundamental, perhaps the most fundamental, demands of Millian thought (v. MILL. STUART 1.). The meaning, if not the term, of common sense is moreover, in a certain sense, implicit in all the specific forms of rationalism ([v.] Plato, Plotinus, Descartes). For Leibniz (v.), from common sense "c'est-à-dire de l'esprit même" come the ideas of space, extension, figure, motion..., the common sensibles of Aristotle (cf. Nouveaux essais..., II, ch. 5). Kant (v.) speaks of common sense as the presupposition of universally valid aesthetic judgments: it is to be understood as "common feeling": it is not a special sense, "but only the effect of the free play of our cognitive faculties" (Kritik d. Urteilskraft, part 1, sec. 1, I, I, §§ 20-22; Ital. trans., Bari 1938, pp. 79-82). F. Lamennais (v.) raised common sense to the sole criterion of certainty, as the expression of general and common reason.

In Neo-Scholasticism common sense has for the most part been accepted in a positive sense, with a meaning analogous to Reid's, though less systematic: "sens commun ou intelligence naturelle," "la raison spontanée et primitive" (R. Garrigou-Lagrange, op. cit. in bibl., p. 1, 15): it would therefore indicate the natural way of thinking and judging of the human spirit, to which there corresponds, on the theoretical plane, "that natural and objective realism... which is, one might say, as Bergson puts it, 'la métaphysique naturelle de l'intelligence humaine'" (ibid., pp. 18-19). It is in this sense, more or less, that Aristotelian-Scholastic metaphysics is sometimes characterized as the "philosophy of common sense."

An objective evaluation cannot fail to recognize a positive significance in common sense, in the universality and determinacy of thought. Already Heraclitus (v.) affirmed: "thought is common to all" (Diels, frg. 113; cf. Mullach, I, p. 322). There is at least one notion, the concept of being-non-being, which is in the very essence of thought and universally grounds the first principles of all human discourse. These principles, even if they do not yet, of themselves, serve as elements of a systematic metaphysical conception of being and nature, nevertheless stand at the basis of every attempt that reflective thought undertakes to that end. If, on the other hand, by common sense one means the more or less vast complex of ideas, opinions and even principles on which a historical epoch universally agrees, its significance as truth remains in itself problematic. Common sense, in this acceptation, is in fact, at least in part, a function of customs, culture, civilization, history; nor are its universality and necessity fixed, inasmuch as it welcomes and slowly assimilates, more or less transforming them, new ideas, conceptions, systems. Common sense, thus understood, cannot therefore claim, from the theoretical point of view, an unconditional authority, and its significance must be clarified by reflective thought, which determines its foundations, conditions and causes.

Ugo Viglino