EXISTENCE. — It is the act, fact, or reason by which it can be said that something “is,” and it answers the question “whether it is” (whether it has been or will be).
In the generic meaning of “reason,” existence is the appearance of the predicate in relation to the subject in a proposition, and hence that which lies “at the foundation” of that movement of the spirit which unites them (or separates them) in affirmation (or negation): existence is then understood as a simple abstract conceptual relation proper to logic and also to pure mathematics and the philosophy of values (cf. W. Burkamp, Begriff und Beziehung, Leipzig 1927, § 49 ff.). Its contrary is non-existence, which is “repugnance,” or the contradiction between concepts.
Existence as a fact is given by experimental observation, whereby something can be indicated and identified as a singular reality in history and experience. This is the most common meaning of existence, often used in the concrete form (the existing thing, existences), and it emphasizes the characteristics of the individuality (circumstances, facts, situations...) of something or someone on which the right to make a claim, to accuse, and to defend oneself may be founded. Its contrary is non-existence as “possibility” not yet realized.
Most traditional philosophies stopped at this meaning of “realization of the possible,” although they did not all conceive it in the same way. Thus, for some it is real singularity in opposition to abstract essence; for others it is the contingent reality of the creature insofar as it expresses a relation to divine causality; for still others it is a modification of singular essence whereby the latter is drawn “outside” possibility: ex-sistentia, an etymology restored to favor by the existentialists. And, as these now do (cf. M. Heidegger, Sein und Zeit, 5th ed., Halle on the Saale 1941, § 9, p. 42 ff.), a distinction came to be made between esse essentia and esse exsistentio (F. Suárez, Disput. Met., disp. 31, sect. VI), a distinction that made the medieval controversy over the distinction between essence and existence still more intricate.
In Thomism, existence is the esse as the “actus essendi” of the singular individual essence; it is therefore a participation in divine actuality received in the essence, with which it forms a real composition, as of act and potency (C. Gent., II, 52–54). Existence as fact, as the realization of experience or history, is a result, a phenomenological consequence of this ontological union. Hence, for St. Thomas, esse is what is most profound in every thing: «Esse est illud quod est magis intimum cuilibet et profundus inest, cum sit formale respectu omnium quae in re sunt» (Sum. Theol., 1st, q. 8, a. 1).
Modern philosophy seems to have remained unaware of the Thomistic notion. Fundamental for later philosophy is the Leibnizian notion, which takes existence as the mode or position of a thing: «Exsistentia nobis concipitur tuquam res nihil habens cum essentia commune, quod tamen fieri nequit, quia oportet plus inesse in conceptu existentia quam non existentia, seu existentiam esse perfectionem; cum ravera nihil aliud sit explicabile in existentia, quam perfectissimam sertam rerum ingredi; ita eodem modo concipimus positionem ut quidem extrinsecum, quod nihil addat rei positus, cum tamen addat modum quo afficitur ab aliis rebus» (L. Couturat, Openades et fragments de Leibniz, Paris 1903, p. 9). Kant’s notion of existence during the pre-critical period approaches this “extrinsicist” notion. Existence is that in a thing which cannot be reduced to a concept, to an element of essence, and therefore “can never be a predicate.” Existence is “the absolute position of a thing”; and for Kant, who here unconsciously approaches the Thomistic position, existence is what ultimately grounds possibility, so that “the intrinsic possibility of things presupposes some existence” (L’Unico argomento possibile per una dimostrazione della esistenza di Dio, in Scritti minori, Italian translation by P. Carabelliese, Bari 1928, p. 44). This is an entirely realist notion, to which Kant always remained faithful, as is demonstrated by the example of the hundred thalers and his critique of the ontological argument: Kant’s defect was that he was content with this crude positivity without investigating further the relations between essence and existence, and consequently came to label as an ontological argument even St. Thomas’s a posteriori proofs of the existence of God.
The distinction between the logical and ontological orders, which was nevertheless preserved in dualist philosophies, disappears in the rationalist monism of Spinoza and later of Hegel. For Spinoza, existence is a predicate of the sole “Substance,” to which it belongs as a necessary requirement (Ethica, part 1, prop. VII). In Hegelian philosophy, existence and reality were separated: existence is the particular, the external phenomenon that is real only insofar as it is subsumed under the Idea, as an element of the whole that is Spirit in the development of its historicity (Scienza della logica, II, sect. 2, chap. 1). For Hegel, therefore, existence characterizes the “appearance” of essence; it is the immediacy that arises from essence, whereby in existence the “indistinct unity” of essence with its immediacy is realized.
In contemporary philosophy, various directions of thought that qualify themselves as “philosophies of existence” (v. ESISTENZIALISMO) have made existence the pillar of opposition to pantheistic and dialectical monism: existence is understood there as the primary reality of the individual “person,” isolated in his own situation in the world and engaged in his tasks: “ec-sisting,” that is, putting oneself outside through the act of personal decision.