“No rational argument will have a rational effect on a man who does not want to adopt a rational attitude.”

“The so-called paradox of freedom is the argument that freedom in the sense of absence of any constraining control must lead to very great restraint, since it makes the bully free to enslave the meek. The idea is, in a slightly different form, and with very different tendency, clearly expressed in Plato.Less well known is the paradox of tolerance: Unlimited tolerance must lead to the disappearance of tolerance. If we extend unlimited tolerance even to those who are intolerant, if we are not prepared to defend a tolerant society against the onslaught of the intolerant, then the tolerant will be destroyed, and tolerance with them. — In this formulation, I do not imply, for instance, that we should always suppress the utterance of intolerant philosophies; as long as we can counter them by rational argument and keep them in check by public opinion, suppression would certainly be unwise. But we should claim the right to suppress them if necessary even by force; for it may easily turn out that they are not prepared to meet us on the level of rational argument, but begin by denouncing all argument; they may forbid their followers to listen to rational argument, because it is deceptive, and teach them to answer arguments by the use of their fists or pistols. We should therefore claim, in the name of tolerance, the right not to tolerate the intolerant. We should claim that any movement preaching intolerance places itself outside the law, and we should consider incitement to intolerance and persecution as criminal, in the same way as we should consider incitement to murder, or to kidnapping, or to the revival of the slave trade, as criminal.”

“A rationalist, as I use the word, is a man who attempts to reach decisions by argument and perhaps, in certain cases, by compromise, rather than by violence. He is a man who would rather be unsuccessful in convincing another man by argument than successful in crushing him by force, by intimidation and threats, or even by persuasive propaganda.”

“A rationalist is simply someone for whom it is more important to learn than to be proved right; someone who is willing to learn from others - not by simply taking over another's opinions, but by gladly allowing others to criticize his ideas and by gladly criticizing the ideas of others”

“Whenever a theory appears to you as the only possible one, take this as a sign that you have neither understood the theory nor the problem which it was intended to solve.”

“Historically, all ethics undoubtedly begin with religion; but I do not now deal with historical questions. I do not ask who was the first lawgiver. I only maintain that it is we, and we alone, who are responsible for adopting or rejecting some suggested moral laws; it is we who must distinguish between the true prophets and the false prophets. All kinds of norms have been claimed to be God-given. If you accept 'Christian' ethics of equality and toleration and freedom of conscience only because of its claim to rest upon divine authority, then you build on a weak basis; for it has been only too often claimed that inequality is willed by God, and that we must not be tolerant with unbelievers. If, however, you accept the Christian ethics not because you are commanded to do so but because of your conviction that it is the right decision to take, then it is you who have decided.”

“Science may be described as the art of systematic oversimplification.”