Identity and difference

Philipp Rosemann examines what he describes as the “fundamental principle of Thomist ontology” in Omne ens est aliquid. Introduction a la lecture du ‘systeme’ philosophique de saint Thomas d’Aquin. The principle is stated in the title, and stated baldly it is an utter truism. When elaborated, though, it points to the “dialectical” character of Thomist metaphysics.

To be some thing, a thing needs to be in a context. Rosemann quotes Alphonse de Waelhens: “quelque chose qui serait donne seul ne serait pas quelque chose ” (49): Nothing that stands alone is some thing. A window is a window in the context of wall, air, light, outside, inside. If you remove this context, there is no window, yet at the same time these other things do not constitute the substance of the window. Hence, “Tout etant n’est quelque chose que par rapport a d’autres etants dont il se distingue” (49): A being is not some thing other than by relation with other beings form which it distinguishes itself.

A thing is a particular something then because of the “circular” relationship between its identity, its being unum and indivisible, and its separation from other things. Subsistence, Thomas says, is a things capacity to return to its essence ( redire ad essentiam suam ). Rosemann explains that “Etre, c’est retourner sur soi; c’est etre reflexif ou circulaire – et ceci puisque etre implique a foir l’identite et la difference, l’ unum et l’ aliquid ” (52).

In the final chapter of his book, Rosemann argues that this play of identity and difference characterizes the life of the Trinity: “Le Pere ne possede aucune identite outre son rapport au Fils; et le Fils, lui, n’est pas personne dont l’identite serait d’une qualconque maniere separable de sa relation au Pere. En Dieu, ce qui constitue les personnes n’est pas, comme dans la creation, une dialectique non resolue entre l’identite et la difference, main plutot le don total du Pere aux autres personnes, d’une part, et, d’autre part, l’ouverture totale des autres personnes a ce don sans retrait.” In short, in God there is no symbolic, but only “le jeu de la difference” (208).