Philip K. Dick (author of Do Androids Dream of Electric Sheep, the book the film is based on)- he wrote the original role of Deckard as a human. "The purpose of this story as I saw it was that in his job of hunting and killing these replicants, Deckard becomes progressively dehumanized. At the same time, the replicants are being perceived as becoming more human. Finally, Deckard must question what he is doing, and really what is the essential difference between him and them? And, to take it one step further, who is he if there is no real difference?"