Principle

PRINCIPLE. - From primum-capere (caput) it is that which comes first, the origin, the beginning (initium, exordium, origo); it corresponds to the Greek ἀρχή: commencement, beginning. From the immediate etymological meaning the figurative one is derived: p. as that which is fundamental, essential, principal (prince). With this meaning (the temporal reference has become, outside of current language, secondary) the term has had wide use in the history of thought.

In the Ionian philosophers the essential problem is the determination of the ἀρχὴ τῆς φύσεως, ἀρχὴ πάντων (Aristotle, Met., I, 3 ff.), that is, of the "primordial" reality (temporal sense) which stands as the "foundation" (ideal meaning) of corporeal beings. In Aristotle the term assumes important and more determinate logical-metaphysical applications. "It belongs to every p. to be that first thing (τὸ πρῶτον) by which a thing is or becomes or is known... Therefore p. are nature, the elements, thought, deliberation, substance, the end" (op. cit., V, 1; and St. Thomas on this passage; cf. Aristotle, Phys., I, 5, 188 a 27: "oportet enim principia nec ex se invicem esse, nec ex aliis, et ex ipsis esse omnia"). Consequently all causes are p.: πάντα γὰρ τὰ αἴτια ἀρχαί: Met., loc. cit.). Aristotle develops in particular the doctrine of logical p.: "p. of demonstration is the immediate proposition, that is, the one which does not derive from another proposition, ὃς μὴ ἔστιν ἄλλη προτέρα (Anal. post., I, 2, 72 a 7). The immediate p. of demonstration (axioms, τὰ πρότερα, ἄμεσα)" "stand by themselves and it is necessary that they be indemonstrable" (ibid., chs. 3 and 2). The p. "among all the most certain," of which demonstration is not possible, is that of contradiction (v.): "it is impossible for the same thing at the same time to belong and not belong to the same thing." To this p. every demonstration is ultimately referred: "for it is by its nature (φύσει) the p. of all the other axioms" (Met., IV, 3, 1005 b 19, 32; cf. ibid., 4, and Sum. Theol., 1a-2ae, q. 94, a. 2: "Super hoc principium omnia alia fundantur"). In the ontological order, the p. or constitutive moments of corporeal reality are matter and form (Aristotle, Phys., I, 7 ff., v. HYLE-

MORPHISM); and the supreme p. of becoming, "on which heaven and nature depend," is the act "pure," "per se ipsum," God (Met., XII, chs. 6-7, 9).

From Scholasticism the term is taken up again with the richness of Aristotelian references (definition in Sum. Theol., 1a, q. 33, a. 1 c.). Furthermore, in relation to the Trinitarian mystery, the distinction (uncertain in Aristotle) between cause and p. is made precise, while cause always implies, in the effect, a relation of real dependence in being ("causa est per se influens esse in aliud"), p. can also indicate a simple relation of origin-consequence (cf. St. Thomas, De potentia, q. 10, a. 1 ad 10; Sum. Theol., 1a, q. 27).

In modern philosophy, while certain traditional references have been abandoned, together with the doctrines they were inspired by, the use of the term has expanded still further. The following principal meanings can be distinguished: a) p. in the logical sense. It is the premise of deduction (v.) or demonstration (v.). In a given order or system it is undemonstrated and indemonstrable: first, immediate p. But it is sometimes taken in a broader sense, as a premise that is not immediate either. Besides the indicated distinction (immediate-mediate p.), the p. is universal, if it refers to the transcendental order of reality and therefore holds for every field of knowledge (e.g., the p. of identity, contradiction, excluded middle); particular or proper, if it is limited to a determinate field of the real (e.g., the p. of mathematics). It is rational, if knowable not only from experience, but also rationally (a priori) through intuition and analysis of the pure concepts or values of thought; empirical, if derived from experience (v.). In opposition to positivist tendencies which hold every p. to be exclusively founded on and measured by experience, or due to a free choice for practical purposes or interests, it must be held that rational p. are the fruit of an intellectual intuition: always referred to experience as regards the real content of their terms (subject and predicate), they depend, in their formal meaning (relation of belonging of the terms, affirmation-negation) on the original intellectual perception of being and its values. The p. is finally purely explicative or analytic, if in it the predicate adds nothing to the subject; synthetic, if the predicate (whether a priori or a posteriori) is additive of a determination not formally contained in the subject (cf. E. Kant, Kritik der reinen Vernunft, Transz. Logik, l. II, ch. 2).

b) P. in the gnoseological sense: it indicates that which in the theory of knowledge (v.) is held to be self-evident and true, and therefore as the foundation of a critical system of knowing. According to the various tendencies such a p. is sometimes placed either in an immediate datum of experience (self-consciousness, sensation, moral experience, etc.) or in an abstract logical-metaphysical p.

c) P. in the real-ontological sense. It is a being or reality on which another reality depends. Every cause (v.) is a p. in this sense: extrinsic p., the efficient and final cause; intrinsic p., that is, constitutive of reality itself, the material and formal cause. In Christian thought God is the efficient-transcendent p., and therefore not constitutive, of all reality. In pantheism and monism (v.) the Absolute (v.) is the immanent p., and therefore also constitutive, of the finite. The intrinsic-ontological p., rather than "realities," are to be understood as metaphysical "moments" of reality (principia "ut quibus"). In Thomism the one most simple reality, without any composition of constitutive p., is God; every finite being instead involves composition of metaphysical p. (act-potency, essence-being, matter-form, substance-accidents).

d) P. as "maxim." It indicates the general directive rules of action, expressed in judgments of value: aesthetic, ethical, juridical, political, religious p., etc. "Intellectus principiorum" (in the ethical field "synderesis," [v.]) is what St. Thomas calls the natural aptitude and disposition of the mind to formulate the first speculative-practical p. (Sum. Theol., 1a, q. 79, a. 12; cf. 1a-2ae, q. 51, a. 1, and In Ethic. ad Nicom., l. VI, lect. 5, nn. 1178-79).

e) P. in the psychological sense. It is the source or cause of psychic activities: the person (v.) as "principium quod" or subject of attribution of the action; nature, the soul, the faculty (v.) as "principium quo" or root and ontological condition determining the action.

f) P. as law or general explanatory hypothesis (or directive-methodological rule of research) of the facts and phenomena of nature, e.g.: p. of the conservation of energy, p. of inertia, p. of indeterminacy, etc.

g) In a general sense, p. is that which founds, explains, gives reason for a reality, a fact, e.g.: vital p., p. of individuation (v.). Said of a science, a system, a doctrine, p. means the fundamental element or truth of it (cf. Descartes, Principia philosophiae; Berkeley, Principles of human knowledge, etc.).

With a technical meaning, in Fichtean transcendental idealism the absolutely first p. expresses "that act which does not present itself, nor can present itself, among the empirical determinations of our consciousness, but rather stands as the basis of every consciousness and alone makes it possible." Such a p. is placed by Fichte in the I as absolute self-positing (Wissenschaftslehre, part 1, § 1; Italian trans. by A. Tilgher, 2nd ed., Bari 1925, p. 51 ff.).

Ugo Viglino