It seems unlikely that any author would deny the influence of others on his work. Yet the more the author seeks to identify all his sources, the more he may convey the impression that what is left over, when those sources are accounted for, is indubitably his own. But there is bound to be a moiety that he has not found nor isolated; all writing is filled with what Jonathan Lethem calls “quotations without inverted commas.” Here are a few words from Lethem’s remarkable essay “The Ecstasy of Influence,” which is well worth reading.

“The kernel, the soul—let us go further and say the substance, the bulk, the actual and valuable material of all human utterances—is plagiarism. For substantially all ideas are secondhand, consciously and unconsciously drawn from a million outside sources, and daily used by the garnerer with a pride and satisfaction born of the superstition that he originated them; whereas there is not a rag of originality about them anywhere except the little discoloration they get from his mental and moral caliber and his temperament, and which is revealed in characteristics of phrasing.”

– Jonathan Lethem, “The Ecstasy of Influence: A Plagiarism”