What a good thing Adam had — when he said a good thing, he knew nobody had said it before. – Mark Twain, 1867

A learned historian declared to me of a contemporary, that the latter had appropriated his researches; he might, indeed, and he had a right to refer to the same originals; but if his predecessor had opened the sources for him, gratitude is not a silent virtue. – Isaac D’Israeli, “Quotation,” A Second Series of Curiosities of Literature

[T]here are aphorisms that, like airplanes, stay up only while they are in motion. – Vladimir Nabokov, The Gift, 1963, translated from Russian by Michael Scammell