Doubt is the offspring of knowledge: the savage never doubts at all.

The philosophic spirit of inquiry may be traced to brute curiosity, and that to the habit of examining all things in search of food. Artistic genius is an expansion of monkey imitativeness.

We live between two worlds; we soar in the atmosphere; we creep upon the soil; we have the aspirations of creators and the propensities of quadrupeds. There can be but one explanation of this fact. We are passing from the animal into a higher form, and the drama of this planet is in its second act.

There is a certain class of people who prefer to say that their fathers came down in the world through their own follies than to boast that they rose in the world through their own industry and talents. It is the same shabby-genteel sentiment, the same vanity of birth which makes men prefer to believe that they are degenerated angels rather than elevated apes.

What a state of society is this in which freethinker is a term of abuse, and in which doubt is regarded as sin?

A religion so cheerless, a philosophy so sorrowful, could never have succeeded with the masses of mankind if presented only as a system of metaphysics. Buddhism owed its success to its catholic spirit and its beautiful morality.

Our enlightened posterity will look back upon us who eat oxen and sheep, just as we look upon cannibals.