It is undesirable to believe a proposition when there is no ground whatever for supposing it true

The objections to religion are of two sorts - intellectual and moral. The intellectual objection is that there is no reason to suppose any religion true; the moral objection is that religious precepts date from a time when men were more cruel than they are and therefore tend to perpetuate inhumanities which the moral conscience of the age would otherwise outgrow.

If an opinion contrary to your own makes you angry, that is a sign that you are subconsciously aware of having no good reason for thinking as you do.

Men fear thought as they fear nothing else on earth - more than ruin, more even than death. Thought is subversive and revolutionary, destructive and terrible, thought is merciless to privilege, established institutions, and comfortable habits; thought is anarchic and lawless, indifferent to authority, careless of the well-tried wisdom of the ages. Thought looks into the pit of hell and is not afraid ... Thought is great and swift and free, the light of the world, and the chief glory of man.

(on A History of Western Philosophy) I was sometimes accused by reviewers of writing not a true history but a biased account of the events that I arbitrarily chose to write of. But to my mind, a man without a bias cannot write interesting history - if, indeed, such man exists.

The degree of one's emotions varies inversely with one's knowledge of the facts - the less you know the hotter you get.

In mass cruelty, the expulsions of Germans ordered by the Russians fall not very far short of the atrocities perpetrated by the Nazis.