The whole world is carried on on the credit system; if every one were to demand payment in hard cash, there would be universal bankruptcy. We think as we do mainly because other people think so. But if every one stands on every one else, what does the bottom man stand on?
 Samuel Butler, The Note-Books of Samuel Butler (1912). copy citation

Context

“For example: A man questions his own existence; he applies first to the court of mother-wit and is promptly told that he exists; he appeals next to reason and, after some wrangling, is told that the matter is very doubtful; he proceeds to the equity of that reasonable faith which inspires and transcends reason, and the judgment of the court of first instance is upheld while that of reason is reversed.
Nevertheless it is folly to appeal from reason to faith unless one is pretty sure of a verdict and, in most cases about which we dispute seriously, reason is as far as we need go.
The Credit System
The whole world is carried on on the credit system; if every one were to demand payment in hard cash, there would be universal bankruptcy. We think as we do mainly because other people think so. But if every one stands on every one else, what does the bottom man stand on? Faith is no foundation, for it rests in the end on reason. Reason is no foundation, for it rests upon faith.
Argument
We are not won by argument, which is like reading and writing and disappears when there is need of such vanity, or like colour that vanishes with too much light or shade, or like sound that becomes silence in the extremes.” source