Around 1980 they (mostly Brett) used to read books on existentialism by Jean-Paul Sartre. He also read Nietzsche, Spinoza, Kant, Lao-Tzu, etc. When in 1997 Brett was asked to choose between Socrates and Diogenes (value being wisdom and consistency), he replied he didn't have any preference and "if I were to choose between wisdom and consistency I'd have to pick wisdom but both are overrated".