Old Man: I am not that now. Have your forgotten? I told you that there are none but temporary Truth-Seekers; that a permanent one is a human impossibility; that as soon as the Seeker finds what he is thoroughly convinced is the Truth, he seeks no further, but gives the rest of his days to hunting junk to patch it and caulk it and prop it with, and make it weather-proof and keep it from caving in on him. Hence the Presbyterian remains a Presbyterian, the Mohammedan a Mohammedan, the Spiritualist a Spiritualist, the Democrat a Democrat, the Republican a Republican, the Monarchist a Monarchist; and if a humble, earnest, and sincere Seeker after Truth should find it in the proposition that the moon is made of green cheese nothing could ever budge him from that position; for he is nothing but an automatic machine, and must obey the laws of his construction.
Mark Twain, What is Man? and Other Stories