"If I have seen further, it is by standing on the ShouldersOfGiants. - IsaacNewton
The idea that there are degrees of originality and synthesis in any new work; thus, even the most original concepts have some antecedents, while even clearly derivative works have some amount of imagination in their production.
"What has been will be again, what has been done will be done again; there is NothingNewUnderTheSun" (Ecclesiastes 1:1-13)