Nothing is more unworthy of a wise man, or ought to trouble him more, than to have allowed more time for trifling, and useless things, than they deserve.

May I do to others as I would that they should do unto me.

Remember our words, then, and whatever is your aim let virtue be the condition of the attainment of your aim, and know that without this all possessions and pursuits are dishonourable and evil.

You can't do good if you don't feel good.

I know too well that these arguments from probabilities are imposters, and unless great caution is observed in the use of them, they are apt to be deceptive.

To love rightly is to love what is orderly and beautiful in an educated and disciplined way.

I have hardly ever known a mathematician who was capable of reasoning.