W. Somerset Maugham said this quote
“ It looked as though you did not act in a certain way because you thought in a certain way, but rather that you thought in a certain way because you were made in a certain way. Truth had nothing to do with it. There was no such thing as truth. Each man was his own philosopher (...). The thing then was to discover what one was and one's system of philosophy would devise itself. It seems to Philip that there were three things to find out: man's relation to the world he lives in, man's relation to the men among whom he lives, and finally man's relation to himself. ”