Some say change systems if you want to improve men. Their opponents say change men if you want to change systems. Both state partial truths, both suffer from their limitation of refusing to acknowledge that the argument of the other side is essential to a complete judgement. The animal hungers and aggressive urges in human nature account for many or most of our more serious troubles: they cannot be altered as easily as we alter policies.
-- Notebooks Category 13: Human Experience > Chapter 2: Living in The World > # 58