"Every great heretic has always exhibited three remarkable characteristics in combination.
First, he picked out some mystical idea from the Church's bundle or balance of mystical ideas.
Second, he used that one mystical idea against all the other mystical ideas.
Third (and the most singular), he seems generally to have had no notion that his own favorite mystical idea was a mystical idea, at least in the sense of a mysterious or dubious or dogmatic idea.
With a queer uncanny innocence, he seems always to have taken this one thing for granted. He assumed it to be unassailable, even when he was using it to assail all sorts of similar things.
The most popular and obvious example is the Bible. To an impartial pagan or sceptical observer, it must always seem the strangest story in the world; that men rushing in to wreck the temple, overturning the altar and driving out the priest, found there certain sacred volumes inscribed 'Psalms' or 'Gospels'; and (instead of throwing them on the fire with the rest) began to use them as infallible oracles rebuking all the other arrangements. If the sacred high altar was all wrong, why were the secondary sacred documents necessarily all right?