“Books must follow sciences, and not sciences books.”

“In science, “fact” can only mean “confirmed to such a degree that it would be perverse to withhold provisional assent.” I suppose that apples might start to rise tomorrow, but the possibility does not merit equal time in physics classrooms.”

“No one indeed believes anything unless he has first thought that it it to be believed.”

“It is a popular delusion that the scientific enquirer is under an obligation not to go beyond generalisation of observed facts…but anyone who is practically acquainted with scientific work is aware that those who refuse to go beyond the facts, rarely get as far.”

“The law of causality, I believe, like much that passes muster among philosophers, is a relic of a bygone age, surviving, like the monarchy, only because it is erroneously supposed to do no harm.”

“It is not so much that I have confidence in scientists being right, but that I have so much in nonscientists being wrong.”