Who said “Mathematics may be defined as the subject in which we never know what we are talking…”?

“What would life be without arithmetic, but a scene of horrors?”

“Yet what are all such gaieties to me whose thoughts are full of indices and surds?”

“Stand firm in your refusal to remain conscious during algebra. In real life, I assure you, there is no such thing as algebra.”

“So-called professional mathematicians have, in their reliance on the relative incapacity of the rest of mankind, acquired for themselves a reputation for profundity very similar to the reputation for sanctity possessed by theologians.”

“Mathematics may be compared to a mill of exquisite workmanship, which grinds your stuff to any degree of fineness; but, nevertheless, what you get out depends on what you put in; and as the grandest mill in the world will not extract wheat flour from peas cods, so pages of formulae will not get a definite result out of loose data.”

“All movements go too far.”

“Drunkenness is temporary suicide.”

“All human activity is prompted by desire.”

“No one gossips about other people's secret virtues.”

“There is much pleasure to be gained from useless knowledge.”

“The good life is one inspired by love and guided by knowledge.”