Now these ideas – Go into thy inner reality and there you will find truth – sound very much like Descartes’ cogito ergo sum (I think, therefore I am). But the difference is that in Deseartes, the self-certainty of the ego is the principle of mathematical evidence – he derives from this his rational system of nature – while for Augustine the inner evidence is the immediacy of having God. So he says, after saying “go into thyself,” “And after you have your soul immutable, transcend yourselves i. e., in your soul is something which transcends your soul, something immutable, namely, the Divine Ground. It is the immediate awareness of that which is unconditional, to which he refers here. This is certainly not an argument for the existence of God, but it is a way of showing that God is presupposed in the situation of doubt about Him. “While not seeing what we believe, we see the belief in ourselves.” i. e. , we see the situation of being grasped by something unconditional.