When two men of science disagree, they do not invoke the secular arm; they wait for further evidence to decide the issue, because, as men of science, they know that neither is infallible. But when two theologians differ, since there is no criteria to which either can appeal, there is nothing for it but mutual hatred and an open or covert appeal to force.

On the one hand, philosophy is to keep us thinking about things that we may come to know, and on the other hand to keep us modestly aware of how much that seems like knowledge isn't knowledge

To modern educated people, it seems obvious that matters of fact are to be ascertained by observation, not by consulting ancient authorities. But this is an entirely modern conception, which hardly existed before the seventeenth century.

A man of Seville is shaved by the Barber of Seville if and only if the man does not shave himself. Does the barber shave himself?

In action, in desire, we must submit perpetually to the tyranny of outside forces; but in thought, in aspiration, we are free, free from our fellowmen, free from the petty planet on which our bodies impotently crawl, free even, while we live, from the tyranny of death.

The Stoic assures us that what is happening now will happen over and over again. [If so, Providende would] ultimately grow weary through despair.

A man's acts are partly determined by spontaneous impulse, partly by the conscious and unconscious effects of the various groups to which he belongs.