Emerson copied out long passages in which Goethe talks about originality and the influence of others. Far from feeling a need to do nothing except what is completely original and novel, Goethe actually defines genius as “the faculty of seizing and turning to account every thing that strikes us.” He protested that he himself would have got nowhere “if this art of appropriation were considered as derogatory to genius.”
– from Robert D. Richardson Jr.’s Emerson: The Mind on Fire.
The words “art of appropriation” have come to refer to the post-modern approach of artists like Sherrie Levine. But I think it is closer to the spirit of the quote to understand it as characterizing the inclusive modernism of Ives, Mahler, Berg, Stravinsky, Rochberg, Harbison, etc. (as contrasted with the more tightly focussed modernism of Webern, Varèse, Feldman, and Babbitt.)