The Church no longer contends that knowledge is in itself sinful, though it did so in its palmy days; but the acquisition of knowledge, even though not sinful, is dangerous, since it may lead to pride of intellect, and hence to a questioning of the Christian dogma.

In the visible world, the Milky Way is a tiny fragment; within this fragment, the solar system is an infinitesimal speck, and of this speck our planet is a microscopic dot. On this dot, tiny lumps of impure carbon and water, of complicated structure, with somewhat unusual physical and chemical properties, crawl about for a few years, until they are dissolved again into the elements of which they are compounded.

What is wanted is not the will to believe, but the will to find out, which is the exact opposite.

There is as much difference between a collection of mentally free citizens and a community molded by modern methods of propaganda as there is between a heap of raw materials and a battleship.

If throughout your life you abstain from murder, theft, fornication, perjury, blasphemy, and disrespect toward your parents, church, and your king, you are conventionally held to deserve moral admiration even if you have never done a single kind, generous or useful action. This very inadequate notion of virtue is an outcome of taboo morality, and has done untold harm.

The true function of logic ... as applied to matters of experience ... is analytic rather than constructive; taken a priori, it shows the possibility of hitherto unsuspected alternatives more often than the impossibility of alternatives which seemed prima facie possible. Thus, while it liberates imagination as to what the world may be, it refuses to legislate as to what the world is

Nothing is so exhausting as indecision, and nothing is so futile.