Science is not a substitute for common sense, but an extension of it.

The three main medieval points of view regarding universals are designated by historians as realism, conceptualism, and nominalism. Essentially these same three doctrines reappear in twentieth-century surveys of the philosophy of mathematics under the new names logicism, intuitionism, and formalism.

Language is conceived in sin and science is its redemption.

Life is what the least of us make the most of us feel the least of us make the most of.

An indirect quotation we can usually expect to rate only as better or worse, more or less faithful, and we cannot even hope for astrict standard of more and less; what is involved is evaluation, relative to special purposes, of an essentially dramatic act.

The lore of our fathers is a fabric of sentences. In our hands it develops and changes, through more or less arbitrary and deliberate revisions and additions of our own, more or less directly occasioned by the continuing stimulation of our sense organs. It is a pale gray lore, black with fact and white with convention. But I have found no substantial reasons for concluding that there are any quite black threads in it, or any white ones.

Theory may be deliberate, as in a chapter on chemistry, or it may be second nature, as in the immemorial doctrine of ordinary enduring middle-sized physical objects.