I know that all revolutions must have ideologies to spur them on. That in the heat of conflict these ideologies tend to be smelted into rigid dogmas claiming exclusive possession of the truth, and the keys to paradise, is tragic. Dogma is the enemy of human freedom. Dogma must be watched for and apprehended at every turn and twist of the revolutionary movement. The human spirit glows from that small inner light of doubt whether we are right, while those who believe with complete certainty that they possess the right are dark inside and darken the world outside with cruelty, pain, and injustice.

Saul Alinsky, in his Rules for Radicals.