Organic life, we are told, has developed gradually from the protozoon to the philosopher, and this development, we are assured, is indubitably an advance. Unfortunately it is the philosopher, not the protozoon, who gives us this assurance.

The opinions that are held with passion are always those for which no good ground exists; indeed the passion is the measure of the holders lack of rational conviction. Opinions in politics and religion are almost always held passionately.

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.

In a logically perfect language, there will be one word and no more for every simple object, and everything that is not simple will be expressed by a combination of words, by a combination derived, of course, from the words for the simple things that enter in, one word for each simple component.

Love as a relation between men and women was ruined by the desire to make sure of the legitimacy of children.

Hatred of enemies is easier and more intense than love of friends. But from men who are more anxious to injure opponents than to benefit the world at large no great good is to be expected.

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