“The psychology of quotation in literature is analogous to that in music: ‘Even if a text is wholly quotation, the condition of quotation itself qualifies the text and makes it so far unique. Thus a quotation from Marvell by Eliot has a force slightly different from what it had when Marvell wrote it. Though the combination of words is unique it is read, if the reader know his words either by usage or dictionary, with a shock like that of recognition. The recognition is not limited, however, to what was already known in the words; there is a perception of something previously unknown, something new which is a result of the combination of the words, something which is literally an access of knowledge.’”

—Donald Jay Grout, a footnote from A History of Western Music, third edition, 1980. He is quoting R.P. Blackmur, Form and Value in Modern Poetry.