Yes. It is evidently false that the soul is of the substance of God because it is not a pure act like God.
Manifeste falsum est animam esse de substantia Dei quia non est actus purus, sicut Deus.
Although the soul is a simple form in its essence, yet it is not its own existence, but is a being by participation.
Etsi sit forma simplex secundum suam essentiam, non tamen est suum esse, sed est ens per participationem.
The human soul is sometimes in a state of potentiality to the act of intelligence -- acquires its knowledge somehow from things--and thus has various powers; all of which are incompatible with the Divine Nature, Which is a pure act--receives nothing from any other--and admits of no variety in itself.
Anima humana est quandoque intelligens in potentia, et scientiam quodammodo a rebus acquirit, et habet diversas potentias, quae omnia aliena sunt a Dei natura, qui est actus purus, et nihil ab alio accipiens, et nullam in se diversitatem habens.
Augustine (De Orig. Animae iii, 15) mentions certain opinions which he calls "exceedingly and evidently perverse, and contrary to the Catholic Faith," among which the first is the opinion that "God made the soul not out of nothing, but from Himself."
Augustinus, in libro de origine animae, enumerat quaedam quae dicit esse multum aperteque perversa, et fidei Catholicae adversa; inter quae primum est, quod quidam dixerunt "Deum animam non de nihilo, sed de seipso fecisse".