Nothing great in science has ever been done by men, whatever their powers, in whom the divine afflatus of the truth-seeker was wanting.

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.

That man, I think, has had a liberal education, who has been so trained in youth that his body is the ready servant of his will.

If there is anything in the world which I do firmly believe in, it is the universal validity of the law of causation.

Make up your mind to act decidedly and take the consequences. No good is ever done in this world by hesitation.

It is wrong for a man to say that he is certain of the objective truth of any proposition unless he can produce evidence which logically justifies that certainty.

Veracity is the heart of morality.