“An algorithm must be seen to be believed.”

“Beware of bugs in the above code; I have only proved it correct, not tried it.”

“The best programs are written so that computing machines can perform them quickly and so that human beings can understand them clearly. A programmer is ideally an essayist who works with traditional aesthetic and literary forms as well as mathematical concepts, to communicate the way that an algorithm works and to convince a reader that the results will be correct.”

“Science is what we understand well enough to explain to a computer; art is everything else.”

“I believe in doubt. I believe in keeping clear of believers.”

“I have seen a sparrow becoming the world's end”

“What I believe is not what I say I believe; what I believe is what I do.”