Chapter 12 — That God is not in a genus

We infer from the above that God is not contained within any genus as a species. For a specific difference added to a genus constitutes a species. Hence the essence of any species possesses something over and above its genus. But being itself, which is God’s essence, does not contain within itself anything that is added to something else. Accordingly, God is not a species of any genus.

Furthermore, since genus contains specific differences potentially, in every being composed of genus and differences, act is commingled with potency. But we have shown that God is pure act without any commingling of potency. Therefore, his essence is not composed of genus and differences; and so he is not in any genus.