Few things have done more harm than the belief on the part of individuals or groups (or tribes or states or nations or churches) that he or she or they are in sole possession of the truth: especially about how to live, what to be and do - and that those who differ from them are not merely mistaken, but wicked or mad: and need restraining or suppressing.
Isaiah BerlinThe underlying assumption that human nature is basically the same at all times, everywhere, and obeys eternal laws beyond human control, is a conception that only a handful of bold thinkers have dared to question.
Isaiah Berlin