“[If a man] postpone[s] any open acknowledgement... that his own faith is in direct opposition to the assumptions on which all the conversation of his new friends [are] based... he will be in a false position. He will be silent when he ought to speak and laugh when he ought to be silent. He will assume, at first only by his manner, but presently by his words, all sorts of cynical and sceptical attitudes which are not really his. But... they may become his. All mortals tend to turn into the thing they are pretending to be.”