We prefer to think that the absence of inverted commas guarantees the originality of a thought, whereas it may be merely that the utterer has forgotten its source. – Clifton Fadiman, The American Treasury, 1455-1955, 1955

The borrowing is often honest enough, and comes of magnanimity and stoutness. A great man quotes bravely and will not draw on his invention when his memory serves him with a word as good. – Ralph Waldo Emerson, “Quotation and Originality,” Letters and Social Aims, 1876

Quotation, like much better things, has its abuses. One may quote till one compiles. The ancient lawyers used to quote at the bar till they had stagnated their own cause. – Isaac D’Israeli, “Quotation,” A Second Series of Curiosities of Literature