A Philosophical Precursor to the Theory of Essence and Existence in St. Thomas Aquinas

A PHILOSOPHICAL PRECURSOR TO THE THEORY OF ESSENCE AND EXISTENCE IN ST. THOMAS AQUINAS IN THIS PAPER I wish to present an important precursor, hitherto unnoticed, to the theory of essence and existence in the thought of St. Thomas Aquinas. It comes from an ancient pagan context and throws considerable light upon the whole problem of whether the distinction between essence and existence is real or not. I have in mind a series of passages from the Enneads of Plotinus; their principal motifs are significantly repeated in the anonymous commentary on the Parmenides attributed to Porphyry,1 and they are further systematized in the work of Proclus. Indeed too, I think, the whole context of Boethius's De Hebdomadibus in a more limited fashion owes much to Plotinus here.2 What I wish to show, however, is not simple textual correspondence, but a similar philosophical approach to a similar problem. Before coming to Plotinus, I sha11 first present the principal points of the Thomistic distinction and then attempt to relate this to the wider problems of nature and grace, natural capacity and the vision of God's essence. For the sake of simplicity and brevity I shall confine myself almost exclusively to the question of composition in either immaterial substances or created substances in general. Unlike the Spanish philosopher Avicebron and all the Neoplatonists , St. Thomas held that spiritual substances (human souls and angels) do not include matter. Instead, following 1 By P. Hadot, Porphyre et Victorinus, Volumes I and II, Etudes Augustiniennes , Paris, 1968. 2 On this see below. 219 KEVIN CORRlGAN Avicenna and St. Aihert, they are compounded. of essence, or form, and being (esse), and these elements are related to each other as potency to act. In an early work, De Ente et Essentia, Thomas argues for the distinction as follows: every essence can be understood without knowing anything about its existence. One can know, for example, what a man or a phoenix is without knowing whether or not it actually exists. Therefore existence is different from essence, unless there is something whose essence is existence, in which case this Being is one and primary. In all created things, however, existence is not contained in the notion of essence and must, therefore, come from outside the essence and enter into composition with it. Only in God are existence and essence identical (De Ente, C. VI, pp. 34, 6-35, 2; Roland-Gosselin). Is this distinction real or conceptual? In the De Veritate 3 and the Commentary on the Sentences 4 these two intrinsic principles of the creature are said to be really distinct. But in the De Ente this is not specified. What does the distinction mean? Essence refers to what is expressed by the definition of a thing; existence, or Being, indicates that the individual is and that it depends upon a prime cause. In every created spiritual substance we find a quality, the substance itself and its existence which is not the substance (quod non est substantia ejus; Contra Gent. II, 53) . Intelligence receives its existence from God, but its essence is identical with that which it is (De Ente, C. IV, p. 35, 4-6, R-G). Every creature possesses existence, therefore, by participation ; 5 and the substance that participates in existence is something other than the participated existence. Hence, the essence stands as potency to the act of existence which it receives from God. The existence is " that by which it is '', the essence " what sne Veritate 27, 1 ad 8; 1, 1 ad 3 (sed contra). ,. In I Sent.: d. 13, q. 1, a. 3. s ST, I, 61, 2, resp.: De Spir. Oreaturis, 1, 1, 14. ESSENCE AND EXISTENCE IN ST. THOMAS AQUINAS 221 it is". By essence Thomas means not the abstract universal essence, even though it can be grasped abstractly, but the actual essence as found in things. Created substances, then, are composed of " quod est " and something added to them, esse, or " quo est ". Boethius 6 had ·used these terms (quod est and esse) to distinguish the concrete subject and nature in finite things (cf. De Hebdomad., PL. 64, 1311C). For him all things are good in their...