The puritanism of Christianity has played havoc with the moderation that an enlightened and tolerant critical spirit would have produced. I've noticed that in whatever country, county, town, or other region there is a regulation enjoining temperance, the population seems to be entirely composed of teetotallers and drunkards. There's a Bible on that shelf there. But I keep it next to Voltaire - poison and antidote.

From India to Spain, the brilliant civilization of Islam flourished. What was lost to christendom at this time was not lost to civilization, but quite the contrary.

Science is at no moment quite right, but it is seldom quite wrong, and has, as a rule, a better chance of being right than the theories of the unscientific. It is, therefore, rational to accept it hypothetically.

If a man is offered a fact which goes against his instincts, he will scrutinize it closely, and unless the evidence is overwhelming, he will refuse to believe it. If, on the other hand, he is offered something which affords a reason for acting in accordance to his instincts, he will accept it even on the slightest evidence. The origin of myths is explained in this way.

Aristotle and Plato considered Greeks so innately superior to barbarians that slavery is justified so long as the master is Greek and the slave barbarian.

Is there any knowledge in the world which is so certain that no reasonable man could doubt it?

When you meet with opposition, even if it should be from your husband or your children, endeavor to overcome it by argument and not by authority, for a victory dependent upon authority is unreal and illusory.