As to sagacity, I should say that his judgement respecting the warmest place and the softest cushion in a room is infallible, his punctuality at meal times is admirable, and his pertinacity in jumping on people's shoulders till they give him some of the best of what is going, indicates great firmness.

Every great advance in natural knowledge has involved the absolute rejection of authority.

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.

In scientific work, those who refuse to go beyond fact rarely get as far as fact.

Follow humbly wherever and to whatever abyss Nature leads, or you shall learn nothing.

Logical consequences are the scarecrows of fools and the beacons of wise men.

There is no sea more dangerous than the ocean of practical politics none in which there is more need of good pilotage and of a single, unfaltering purpose when the waves rise high.