Thomas Aquinas‘ 'Entity and Essence' (Book Review)

A small mistake in the beginning is a big one in the end, according to the Philosopher in the first book of On the Heavens and the Earth. And as Ibn-Sînâ says in the beginning of his Metaphysics, being and essence are what is first conceived by the intellect.

Thus, to avoid making mistakes out of ignorance of them, and to become familiar with the difficulties they entail, we must point out what is signified by the words “being” and “essence,” and how they are found in diverse things, and how they are related to the logical intentions, genus, species, and difference.

Since we ought to acquire knowledge of what is simple from what is composed, and come to what is prior from what is posterior, so that, beginning with what is easier, we may progress more suitably in learning; we ought proceed from the meaning of the word “being” to that of the word “essence.”