In the NY Times, TR Luhrmann examines the phenomenon of 'boggle lines'--the point at which someone draws the line between what can be accepted into an operational worldview and what seems utterly fantastical. Luhrmann explains that each person's boggle line is different. A person may have no trouble believing God became a mortal being two millennia ago, but may find the prospect of progressive evolution fantastical.
It's also possible that the boggle line is what reinforces to our psyche that we are, in fact, reasonable people--it's what enables faith in the first place. We know what we don't believe so that we know what we do believe, Luhrmann argues.
It might also be because God is unknowable. We see through a glass darkly. Thus Augustine’s echoing cry, at the start of his “Confessions”: “Tell me of thy compassion, O Lord my God, what thou art to me. ‘Say unto my soul, I am thy salvation.’ So speak that I may hear ... Hide not thy face from me.” The long tradition of spiritual literature is full of intense uncertainty about the true nature of a being that can neither be seen nor heard in the ordinary way.
Read the complete article here.