"Many of our moral and political policies are designed to preempt what we know to be the worst features of human nature. The checks and balances in a democracy, for instance, were invented in explicit recognition of the fact that human leaders will always be tempted to arrogate power to themselves. Likewise, our sensitivity to racism comes from an awareness that groups of humans, left to their own devices, are apt to discriminate and oppress other groups, often in ugly ways. History also tells us that a desire to enforce dogma and suppress heretics is a recurring human weakness, one that has led to recurring waves of gruesome oppression and violence. A recognition that there is a bit of Torquemada in everyone should make us wary of any attempt to enforce a consensus or demonize those who challenge it."
Steven Pinker in the introduction to “What is Your Dangerous Idea?” (2007)