Gilson argues that, in Thomas’s mind, “the notion of being underwent a remarkable transformation,” away from the idea of “entity” (essentia) to the idea of being as “the act pointed out by the verb ‘to be.”’ Gilson continues:
In the doctrine of Thomas Aquinas, being has received the full- ness of its existential meaning. . . . [B]ecause it is to act, “to be” is something fixed and at rest in being: esse est aliquid fixum et
quietum in ente. . . . As Thomas Aquinas understands him, God
is the being whose whole nature it is to be such an existential act. This is the reason why his most proper name is, HE IS. After saying this, any addition would be a subtraction. To say that God “is this,” or that he “is that,” would be to restrict his being to the essences of what “this” and “that” are. God “is,” absolutely.22
We should note that the translation of the non-gendered Latin “qui est” as “he is” already constitutes such a subtraction by addition, but we’ll come back to that. Gilson provides the context in which to situate Lacan’s explora- tion of the question of being in Seminar XX. In God, the word “is” loses its copulative function, just as creation itself is liberated from all copulative ne- cessity and conflict in order to become an expression instead of the dynamic being as doing of God, who creates freely, out of nothing, as an expression of unfathomable and gratuitous love, but also against a terrifying hinterland of damnation and eternal bodily torment. I do not refer to Thomas’s account of demons, hell and pre-destination here, but it is vital for a more developed account of Lacan’s Thomism.
In the debates of his time, Thomas opposed the philosophical argu- ment put forward by Avicenna and others that reality adds something to being.23 For Thomas, such an assertion would violate the absolute simplic-
ity of God, and therefore oneness must be understood as something other than a mathematical principle by way of which something is added to something else. Over and against such a definition of singularity, Thomas
22. Étienne Gilson, History of Christian Philosophy in the Middle Ages (London: Sheed & Ward, 1955) 368–69, quoting Aquinas, SCG I: 20, 4.
posits the concept of one as synonymous with being, by way of which nothing can possibly be added to the divine being. Lacan’s “One of ‘pure difference’” alludes to this. In Thomist terms, it is the perfect simplicity of the divine being as pure act—actus purus—with no predicate, copula, distinction or complexity.
This leads Thomas to reject a dualistic interpretation of the one as op- posed to the many, in favour of a less polarized duality in which the multi- tude, being divided, lacks the undivided fullness of the oneness of being. In other words, for anything to become other than God, there must be some limit and boundary to its being—it must be not-all—if it is to exist as dif- ferent from other beings and as distinct from the fullness of God’s being. Otherwise, there would be no created beings at all—the divine plenitude would be all in all.
In one section of the first part of the Summa Theologiae, Thomas rep- resents lack as the condition by way of which each species in its own created perfection reveals something of the divine perfection, so that the fullness of God’s being is better revealed by plurality and diversity than by singularity:
For God brought things into being in order that His goodness might be communicated to creatures, and be represented by them; and because His goodness could not be adequately rep- resented by one creature alone, He produced many and diverse creatures, that what was wanting to one in the representation of the divine goodness might be supplied by another. For goodness, which in God is simple and uniform, in creatures is manifold and divided and hence the whole universe together participates in the divine goodness more perfectly, and represents it better than any single creature whatever.24
From this perspective, as Lacan recognizes, lack becomes the con- dition of there being any beings at all other than God’s being, and the totality of all beings will never amount to the fullness of God’s being. In this account, Thomas’s God is not the philosophical One of ancient phi- losophy and modern theism, but “the One of pure difference.” Lack is not the fantasized deprivation and prohibition associated with the Oedipus complex, but the primordial condition for intelligent, linguistic beings to enjoy a certain freedom in relation to the things around them. If I were to be more than I am, I would cease to be the particular being that I am and become a different being, not a more perfect or complete version of my own being. The relationship between the being of God and other beings is not quantitative but qualitative, not relative but relational—all beings
participate in God, but the divine being participates in no other being for there is no lack or distinction within the being of God that would allow for such participation in a lesser being.