Observatory

One of the surest of tests is the way in which a poet borrows. Immature poets imitate; mature poets steal; bad poets deface what they take, and good poets make it into something better, or at least something different. The good poet welds his theft into a whole of feeling which is unique, utterly different from that from which it was torn; the bad poet throws it into something which has no cohesion. A good poet will usually borrow from authors remote in time, or alien in language, or diverse in interest. Chapman borrowed from Seneca; Shakespeare and Webster from Montaigne. The two great followers of Shakespeare, Webster and Tourneur, in their mature work do not borrow from him; he is too close to them to be of use to them in this way.

—T.S. Eliot, 1921.  Found via a discussion about the “good artists borrow, great artists steal” quote that Steve Jobs purportedly lifted from Pablo Picasso.