Descartes Third Meditation

One of the main premises Descartes’ uses to build his subjective proof of God’s existence in the third meditation which connects directly to the objective one in the fifth, is that he possesses a clear and distinct idea of an infinite substance which he, as a finite substance, could not have created himself, and which therefore must come from the infinite substance itself. This, of course, follows from the causality premise that states that effect, in this case, an idea of God, cannot have more reality that its cause, which, should the idea of God come from Descartes’ mind alone, would be that mind in particular. However, what makes this argument less than perfectly sound for me is that Descartes clearly understands clear and distinct ideas