True science and true religion are twin sisters, and the separation of either from the other is sure to prove the death of both. Science prospers exactly in proportion as it is religious; and religion flourishes in exact proportion to the scientific depth and firmness of its basis.

. . . I fail to find a trace [in Protestantism] of any desire to set reason free. The most that can be discovered is a proposal to change masters. From being a slave of the papacy, the intellect was to become the serf of the Bible.

Science and literature are not two things, but two sides of one thing.

Of moral purpose I see no trace in Nature. That is an article of exclusively human manufacture and very much to our credit.

Science is simply common sense at its best, that is, rigidly accurate in observation, and merciless to fallacy in logic.

The only people, scientific or other, who never make mistakes are those who do nothing.

As for your doctrines I am prepared to go to the Stake if requisite ... I trust you will not allow yourself to be in any way disgusted or annoyed by the considerable abuse & misrepresentation which unless I greatly mistake is in store for you... And as to the curs which will bark and yelp - you must recollect that some of your friends at any rate are endowed with an amount of combativeness which (though you have often & justly rebuked it) may stand you in good stead - I am sharpening up my claws and beak in readiness.