The powers of the mind should be concentrated and turned back upon itself, and as the darkest places reveal their secrets before the penetrating rays of the sun, so will this concentrated mind penetrate its own innermost secrets. Thus will we come to the basis of belief, the real genuine religion. We will perceive for ourselves whether we have souls, whether life is of five minutes, or of eternity, whether there is a God in the universe or none. It will all be revealed to us.
Swami Vivekananda, Raja Yoga