If I may be allowed to speak personally for a moment, I find the presence of God bearing upon my existence and thought so powerfully that I cannot but be convinced of His overwhelming reality and rationality. To doubt the existence of God would be an act of sheer irrationality, for it would mean that my reason had become unhinged from its bond with real being. Yet in knowing God I am deeply aware that my relation to Him has been damaged, that disorder has resulted in my mind, and that it is I who obstruct knowledge of God by getting in between Him and myself, as it were. But I am also aware that His presence presses unrelentingly upon me through the disorder of my mind, for He will not let Himself be thwarted by it, challenging and repairing it, and requiring of me on my part to yield my thoughts to His healing and controlling revelation.
It is only in knowing God that we know we are sinners, that our prideful habits of thinking are the reason we are not able to know God on our own mental power, and thus that we know God only because of the power of his grace.
(PS - The artist that drew this picture of Torrance is HOT!)