Entry 0224: The Self-Evident Connotation of the
Actus Essendi (XI)
In a review of Ralph McInerny’s Boethius and Aquinas, R. D. DiLorenzo writes:
“Diversum est esse et id quod est [is] the principal axiom in De Hebdomadibus. … It is self-evident to Boethius and Thomas that for a thing to be and what it is differ. …
“The tractate De Hebdomadibus … is designed to show that substances are good in that they are but are not, for all that, substantial goods and, furthermore, require, in order both to be and to be good, a first substantial good and existence that everyone calls God. The argument is developed according to a set of axioms which are self-evident. … Diversum est esse et id quod est is the first of these arguments. …“As Aquinas sequentially brings the axioms to bear on one another, he shows how the diversity between esse and id quod est is, first, a diversity arising from different ways of signifying some one thing in speech. … However, the diversity is not only logical but real.” (1)
(1) R. D. DiLorenzo, “Boethius and Aquinas. By Ralph McInerny.