The science, the art, the jurisprudence, the chief political and social theories, of the modern world have grown out of Greece and Rome-not by favour of, but in the teeth of, the fundamental teachings of early Christianity, to which science, art, and any serious occupation with the things of this world were alike despicable.

The foundation of morality is to have done, once and for all, with lying.

The Bible account of the creation of Eve is a preposterous fable.

You may read any quantity of books, and you may almost as ignorant as you were at starting, if you don't have, at the back of yourminds, the change for words in definite images which can only be acquired through the operation of your observing faculties on the phenomena of nature.

It is not who is right, but what is right, that is of importance.

... our "Physick" and "Anatomy" have embraced such infinite varieties of being, have laid open such new worlds in time and space, have grappled, not unsuccessfully, with such complex problems, that the eyes of Vesalius and of Harvey might be dazzled by the sight of the tree that has grown out of their grain of mustard seed.

Agnosticism, in fact, is not a creed, but a method, the essence of which lies in the rigorous application of a single principle. ... Positively the principle may be expressed: In matters of the intellect, follow your reason as far as it will take you, without regard to any other consideration. And negatively: In matters of the intellect, do not pretend that conclusions are certain which are not demonstrated or demonstrable.