The answer is: would have no knowledge of the idea of perfection.
In this, Descartes´ famous proof of the existence of God, he makes the argument that, Descartes, being a man, that is to say, something that does not possess any of the qualities of perfection that God possesses, but being able to fathom an idea about God´s perfection, must mean that God not only exists, but that God himself instilled the idea of perfection in Descartes´s imperfect mind, for otherwise, an imperfect mind, by its imperfect nature, could not think something greater than itself.