Going back to Scholastic ontology:
the verum esse in Thomas Aquinas
What is the foundation of the two determinations of res cogitans as esse perceptum and as esse creatum? In order to elucidate this question, we have to go back before Descartes, to the extent that we see a connection in Scholastic ontology. What needs to be said from the outset is this: the genuine connection between the esse perceptum and the esse creatum is established by the esse verum. The entity, in the manner in which it is grasped, is identical with being in the sense of truly being. The esse creatum qua esse creatum is characterized as the esse bonum et verum. Nothing is gained by this purely formulaic determination. In order to get a hold on the character of res cogitans' being, we need to become clear about how the sense of the verum esse is determined in Scholasticism itself.
§ 29. The connection of the verum and the ens: being-true as a mode of being (De veritate, q. 1, art. 1)
The problem of truth was handled by the entire Scholastic tradition in various manners in conjunction with Aristotle. However, the High Scholastic tradition was the first to provide a comprehensive doctrine of truth. We will interpret Thomas' writing "De veritate" [On Truth] in the Quaestiones disputatae.1 Next to this major question "De veritate," these disputed questions include questions, among others, ''De scientia Dei," "De praedestinatione," "De conscientia," "De libero arbitrio," "De gratia," [On God's Knowledge, On Predestination, On Conscience, On Free Will, On Grace], thus questions of an essentially theological character, while "De veritate" is philosophical in the sense of the High Scholastic tradition.
The "Quaestio prima" is divided into twelve questions (articles): 1. Quid sit veritas [What truth is]. 2. Utrum veritas principalius in intellecu quam in rebus reperiatur [Whether truth is found more principally in the intellect than in things]. 3. Utrum in intellectu componente et dividente sit veritas [Whether truth is in the intellect that combines and divides]. 4. Utrum una tantum veritas sit, qua omnia vera sint [Whether there is one truth alone, by which all true
1. Thomas Aquinas, De veritate. In: Sancti Thomae Aquinatis Quaestiones disputatae, Vol. . II, complectens de veri tate et quaestiones quolibeticas. ["On Truth," in The Disputed Questions of St. Thomas Aquinas, vol. 2, comprising "De Veritate" and "Quodlibetal Questions."] (parma 1859). In: Opera omnia [Complete Works] (Parma 1852ff.), Tomus IX.