The art historian Jacob Isager writes in the introduction to his analysis of Pliny's chapters on art in the "Natural History" that his intention is:to show how Pliny in his encyclopedic work – which is the result of adaptations from many earlier writers and according to Pliny himself was intended as a reference work – nevertheless throughout expresses a basic attitude to Man and his relationship with Nature; how he understands Man's role as an inventor ("scientist and artist"); and finally his attitude to the use and abuse of Nature's and Man's creations, to progress and decay. More specifically, Isager writes that "the guiding principle in Pliny's treatment of Greek and Roman art is the function of art in society", while Pliny "uses his art history to express opinions about the ideology of the state".