Aquinas Day By Day


Aquinas’s Topic: Two senses of Being

Scripture: Ps. 89: 22-4: “I have found David my servant and with my holy oil anointed him. My hand shall always be with him and my arm shall make him strong. The enemy shall never outwit him nor the evil man oppress him.” for Vespers, 2nd Sunday of Ordinary Time

Aquinas’s text: On Being and Essence, written 1252-6.

To understand any discipline or “science” Aquinas starts by clarifying its subject. He does this for logic as well as the other disciplines. A philosopher is inclined to set what he studies within the widest possible context, so Aquinas looks at human reasoning, which is what logic concerns, in relation to the widest of human concepts, the concept of “being.” In an early work devoted to clarifying fundamental philosophical terms—being (ens), essence (essentia), and existence (esse)—Aquinas follows Aristotle’s injunction that knowledge begins with the whole of what is studied and then analyzes it into its parts or principles. He therefore begins with “being,” the broadest term, and distinguishes two senses of being.

[[Since we must acquire knowledge of what is simple form what is composite and must arrive at what is primary from what is secondary, . And since learning is achieved best when we begin with what is easier, we should proceed from what ‘being (ens)’ means to what ‘essence (essentia)’ means.

Consequently, one should note, as the Philosopher says in Metaphysics 5, that being in itself is said in two ways. The first is as it is divided into the ten genera, while the second is as it refers to the truth of propositions. These are different, because anything can be called a being in the second sense, if an affirmative proposition can be formed about it, even if it is nothing positive in reality. In this way, privations and negations are called beings, as when we say that affirmation is opposed to negation or that blindness is in the eye. In the first sense, however, only what is something positive in reality can be called a being. Therefore, blindness and such things are not beings in the first sense of the term. [check trans.]]

Quia vero ex compositis simplicium cognitionem accipere debemus et ex posterioribus in priora devenire, ut, a facilioribus incipientes, convenientior fiat disciplina, ideo ex significatione entis ad significationem essentiae procedendum est.

Sciendum est igitur quod, sicut in V metaphysicae philosophus dicit, ens per se dicitur dupliciter, uno modo quod dividitur per decem genera, alio modo quod significat propositionum veritatem. Horum autem differentia est quia secundo modo potest dici ens omne illud, de quo affirmativa propositio formari potest, etiam si illud in re nihil ponat. Per quem modum privationes et negationes entia dicuntur; dicimus enim quod affirmatio est opposita negationi et quod caecitas est in oculo. Sed primo modo non potest dici ens nisi quod aliquid in re ponit. Unde primo modo caecitas et huiusmodi non sunt entia.

[Introductions and translations © R.E. Houser]