NECESSITÀ

NECESSITY. -

I. Philosophy

There is first of all a metaphysical necessity, or necessity of being as such, which is immutability in the possession of being. In the realm of the possible, it is the necessity of essences as an indivisible and indissoluble belonging of the principles that constitute them in their own degree of being. In the realm of reality, metaphysical necessity is the impossibility of something not existing and constitutes the most perfect degree of the real, to which corruptibility and contingency (q.v.) are opposed; it belongs in its own right to spiritual beings insofar as the absolute immateriality of their essence (q.v.) removes them from every principle of corruption and hence of loss of being. Metaphysical necessity in the strict sense belongs to God, who is Pure Act, Being by essence. However, St. Thomas maintains that even spiritual creatures enjoy an absolute metaphysical necessity, though created: "Sunt enim quaedam in rebus creatis, quae simpliciter et absolute necesse est esse in quibus non est possibilitas ad non esse... Illae res in quibus non est materia, non habent potentiam ad non esse: eas igitur absolute et simpliciter necesse est esse" (C. Gent., II, 30; cf. Aristotle, Met., V, 5, 105 b 10). This doctrine of metaphysical necessity underpins the instance of the "per se necessarium" that governs the third way to demonstrate the existence of God (Sum. Theol., 1a, q. 2, a. 3).

Moreover, metaphysical necessity must also be referred to the properties deriving from the form of spiritual being: immortality, the activity of thought, free will, sociability, morality, and religiosity. In an even more general sense, it is by metaphysical necessity that every power is specified by its proper object: the eye by colors and the other senses by their proper sensibles, appetite by the good, and the intellect by the true (cf. Sum. Theol., 1a, q. 77, a. 3). For the body, there is a negative metaphysical necessity deriving from matter, that is, its corruptibility, since it is composed of contrary elements that tend to separate; for this reason, the immortality that will be granted to the human body at the final resurrection is considered a preternatural divine gift and surpasses every capacity of the human intellect (ibid., suppl., 3a, q. 75, a. 3). Metaphysical necessity therefore embraces the whole sphere of existence: "Necessitas absoluta competit rei secundum id quod est intimum et proximum ei: sive sit forma, sive materia sive ipsa rei essentia" (In V Met., lect. 6; ed. Cathala, Turin 1950, n. 833). From the final cause comes the necessity of the ultimate end (q.v.) and of universal good, which is the object of the will, since once the good is known it cannot but be loved; the necessity of the end entails the necessity of the means that are indispensable for attaining the end itself (Sum. Theol., 1a-2ae, q. 10, a. 1).

Just as in reality the necessity of being is the absolute consistency deriving from the principles of being itself, so in the realm of thought (logical necessity) necessity is the "coherence" or absolute connection between principles and conclusions. Logical necessity therefore pertains first of all to the first principles (of non-contradiction, identity, excluded middle, whole and parts...) called "principia per se nota" insofar as their evidence is immediate for anyone who grasps the meaning of the respective terms (cf. Sum. Theol., 1a, q. 2, a. 1; Aristotle, Anal. Pr., I, 2, 25 a 1). The first principles stand to knowledge (q.v.) and science (q.v.) as essence does to its properties and the end to the means, inasmuch as they are the cause of the necessity of conclusions; therefore, in a strict sense, necessity pertains to apodictic syllogism, which precisely proceeds from necessary premises (Anal. Post., II, 6, 74 b 15 ff.). In this sense, necessary knowledge is opposed to contingent knowledge and to problematic or dialectical knowledge, which leaves open a twofold opposite solution to the problem itself: "Is pleasure to be desired or not? Is the world eternal or not?" (Topica, I, 11, 104 b 1).

At the foundation of the entire Aristotelian-Thomistic doctrine of necessity lies the presupposition of realism, namely that knowledge reflects the being of things and the quality of knowing. The synthesis of subject and predicate in judgment is necessary when the connection of substance and property is likewise necessary in nature, and whoever thinks differently, Aristotle observes forcefully, lies (Met., IX, 10, 1051 b 2 ff.). To this St. Thomas adds in his commentary: "Manifestum est quod dispositio rei est causa veritatis in opinione et oratione... Oportet veritatem et falsitatem quae est in opinione vel oratione reduci ad dispositionem rei sicut ad causam" (In IX Met., lect. 11, nn. 1897-98).

For Aristotle, therefore, the distinction of three modes of knowing—apodictic or necessary, contingent, and problematic—corresponds to three different modes inherent in the very structure of things, in which consists the fundamental ontological truth of which logical truth is the expression in language and in the life of thought (cf. De Interpr., 12, 21 a 34 ff.). Similarly, for St. Thomas, necessity in the processes of thought derives from the things themselves that guide the path of the mind and govern its affirmations and negations in contingent or necessary matters: "Non enim propter nostrum affirmare vel negare mutatur cursus rerum, ut sit aliquid vel non sit, quia veritas nostrae enunciationis non est causa exsistentiae rerum sed potius e converso" (In Periherm., lect. 14; ed. Leonina, 1, p. 65 b). According to Hegel, on the other hand, "the judgment of the concept has as its content the concept" (Encykl., § 178), and this is the judgment of necessity, that is, "of the identity of the content in its distinction," so that the distinction of judgments (categorical, hypothetical, and disjunctive) depends on the different way in which this identity is realized in the unique form of "totality" (ibid., § 177). The "syllogism of necessity" is, for Hegel, that in which "each of the moments has shown itself to be the totality of the moments or expresses the totality returned into itself whose differences are likewise this totality" (ibid., § 193). And Hegel takes the opportunity to observe that it is in this perfect coincidence of form and content that one can alone have the demonstration of the Absolute, glimpsed for the first time, albeit imperfectly, in the so-called ontological argument of St. Anselm, whose defect is merely that the identity of essence and existence in the Absolute is presupposed, that is, taken only as unity in itself—a defect that remains even in Descartes and Spinoza and that, according to Hegel, will be resolved only through thinking or dialectical consideration.

Necessity is therefore the principal modality of being and thought, and its theoretical structure is a function of the different orientation that, in various philosophies, the relationship between being and thought assumes.

II. THEOLOGY: NECESSITY, RELATIVE OR HYPOTHETICAL. Since the reason why a thing cannot but be differs according as it is founded upon its intrinsic causes (essence) or upon extrinsic causes (necessity of attaining an end), it follows that we must speak, besides absolute or metaphysical necessity (founded upon the intrinsic causes of the thing), of relative or hypothetical necessity (deduced from the end to be attained).

The latter is physical when without the thing required the end cannot in any way be attained. It is moral when, although the end could, absolutely speaking, be attained without the thing required, in fact, on account of external and internal difficulties, the end remains, practically, always or almost always unattainable. In the first case we have moral necessity *stricto sensu*; in the second, moral necessity *lato sensu*.

To physical necessity, also called absolute in the hypothetical order in which it exists (cf. Vatican Council, sess. III, cap. 2 [Denz-U, 1786], and can. 3 [Denz-U, 1808]), corresponds physical impotence, which arises either from the very nature of the faculty unequal to the act, e.g., sight is physically incapable of perceiving sounds; or from the lack of some external condition *sine qua non* for the act, e.g., without light and proper distance sight is physically incapable of perceiving colors. To moral necessity, not to be confused with ethical necessity which denotes conformity to the supreme rule of action (v. MORALITY), corresponds moral impotence (v. INCOMODO), which occurs when the faculty, although physically capable of such an act and such an end, nevertheless does not attain it because of obstacles usually insurmountable (cf. Sum. Theol., 1a, q. 82, a. 1). Thus, when it is affirmed that for a suitable knowledge of natural religion moral hypothetical necessity requires, for the human race, the Revelation, it is meant that all and each normal man has within himself the physical capacity to know the whole body of doctrines and religious duties of natural order; yet, in fact, on account of all the difficulties and obstacles, almost the entire human race will never attain this knowledge by its own powers alone; which is to say: it is morally incapable. When, on the other hand, it is said that for knowing the objectively supernatural truths, e.g., the Mysteries, or for performing any salutary act, i.e., meritorious of eternal life, physical, absolute necessity requires Grace as an internal gift, it is meant that the natural faculties of man, intellect and will, are physically incapable of performing such acts of supernatural order, absolutely transcending man, who therefore needs Grace, a divine gift, which is inserted into man as a new principle of activity, strengthening, purifying, and elevating human faculties to the supernatural order (cf. Conc. Carth., can. 5 [Denz-U, 105], Conc. Araus. II, can. 6-7 [Denz-U, 170-80]; Conc. Trid., sess. VI, can. 1, 2, 3 [Denz-U, 81-1-3]).

Besides the foregoing distinction between moral necessity *stricto sensu* or absolute, there is that between necessity of means and necessity of precept, when the end to be attained is specifically eternal salvation. A thing is said to be necessary of means when, either in itself or by virtue of the divine plan, i.e., by positive ordinance of God, it is the only means to obtain eternal life and the aids necessary to attain it, so that its omission, even involuntary, renders salvation impossible.

In the first case such necessity is absolute, and without the thing required the end cannot in any way be attained, nor can it be supplied by another thing. Thus faith, sanctifying Grace. In the second case, however, the thing required is only hypothetically necessary, i.e., it is the only ordinary means for salvation, and in case of impossibility it can be supplied by an extraordinary means: thus the Baptism of water, the Sacrament of Penance for sinners. A thing is said to be necessary of precept when it is required for salvation, but only by a divine precept, so that only culpable omission of it prevents salvation, never an inculpable omission. Thus the reception of Extreme Unction. Finally, as is clear, those things which are necessary of means are also necessary of precept, since he who obliges to the end also obliges to the necessary means.

Necessity also has the meaning of need, i.e., lack of the things necessary for life. In this sense it admits of degrees: it can be extreme, grave, ordinary; and according to the various degrees it gives to him who is subject to it rights more or less strict to the assistance of his fellow men. Necessity finally has the meaning of compulsion, not physical or external, which in that case takes the name of coercion, but of an interior impulse or drive. Necessity is in this case considered as a force to which one cannot resist, and which inevitably draws the will: it is then said that one acts under necessity.

V. FORCE MAJEURE; LIBERTY.