Invisible Frequencies

In his diary, Arthur Koestler contemplates the nature of his faith in something beyond human understanding. After observing that he could not believe in a historic God, he added that nor could he accept "the tale told by an idiot." Then he wrote:

I believe in something beyond the human brain, beyond the range of frequencies visible to the ear; a message written in invisible ink, of which fragments become visible when listening to music, standing on a mountain, praying, reading poetry, being in love, contemplating a beautiful math solution. Fragments of the message have been copied in mutilated versions in the scriptures, the Vedas, etc. But those copies are as inadequate as ignorant monks' copies of antique texts.

That passage comes as close as any I've found to expressing the dilemma of faith: the agony of glimpsing something through a glass darkly, of hearing a sound just beyond the range of human hearing, of sensing a presence when nothing seems to be there.