How could it occur to anyone to demonstrate that God exists unless one has already allowed Himself to ignore Him? A king's existence is demonstrated by way of subjection and submissiveness. Do you want to try and demonstrate that the king exists? Will you do so by offering a string of proofs, a series of arguments? No. If you are serious, you will demonstrate the king's existence by your submission, by the way you live. And so it is with demonstrating God's existence. It is accomplished not by proofs but by worship. Any other way is but a thinker's pious bungling.