Wiki:
...the question of whether Deckard is intended to be a human or a replicant has been an ongoing controversy since the film's release.[63] Both Michael Deeley and Harrison Ford wanted Deckard to be human while Hampton Fancher preferred ambiguity.[64] Ridley Scott has confirmed that in his vision Deckard is a replicant.[65][66] Deckard's unicorn dream sequence, inserted into the Director's Cut, coinciding with Gaff's parting gift of an origami unicorn is seen by many as showing that Deckard is a replicant—as Gaff could have accessed Deckard's implanted memories.[55][67] The interpretation that Deckard is a replicant is challenged by others who believe the unicorn imagery shows that the characters, whether human or replicant, share the same dreams and recognize their affinity,[68] or that the absence of a decisive answer is crucial to the film's main theme.[69] The inherent ambiguity and uncertainty of the film, as well as its textual richness, have permitted viewers to see it from their own perspectives.
