Themes in Blade Runner - Deckard: Human or Replicant?

Deckard: Human or Replicant?

There is a sequence added in the Director's Cut version (that was not in the original theatrical release) where Deckard dreams about a unicorn, and at the end of film finds an origami unicorn that Gaff leaves in Deckard's apartment, possibly suggesting to the viewer (and to Deckard) that Gaff knows about Deckard's dream in the same manner that Deckard knows about Rachael's implanted memories.

Even without considering the unicorn dream scene inserted in the director's cut, there is other evidence which allows for the possibility of Deckard being a replicant, but do not eliminate the possibility of Deckard being human.

• The fact that Deckard's apartment is full of photographs, none of them recent or in color. Replicants have a taste for photographs, because it provides a tie to a non-existent past.
• The scene in which Rachael asks Deckard whether he has passed the Voight-Kampff test himself, and receives no answer.
• The fact that Gaff, who had shown no sympathy for Deckard throughout the film, tells him "You've done a man's job, sir!" after Roy expires, lets Rachael live and does not intervene when she and Deckard leave his apartment.

Relevant opinions from those involved:

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?

• Philip K. Dick wrote the character Deckard as a human in the original novel. The film differs from the book in some ways that provide ambiguity on the issue. For example, the book states explicitly that Deckard passed the Voight-Kampff test, while the movie shows Deckard declining to answer whether he did or not.
• Hampton Fancher (original screenwriter) has said that he wrote the character Deckard as a human, but wanted the film to suggest the possibility that he may be a replicant. When asked, "Is Deckard a replicant?", Fancher replied, "No. It wasn't like I had a tricky idea about Deckard that way." During a discussion panel with Ridley Scott to discuss Blade Runner: The Final Cut, Fancher again stated that he believes Deckard is human (saying that " idea is too complex"), but also repeated that he prefers the film to remain ambiguous: "I like asking the question and I like it to be asked but I think it’s nonsense to answer it. That’s not interesting to me."
• Ridley Scott stated in an interview in 2002 that he considers Deckard a replicant.
• Harrison Ford considers Deckard to be human. "That was the main area of contention between Ridley and myself at the time," Ford told interviewer Jonathan Ross during a BBC1 Hollywood Greats segment. "I thought the audience deserved one human being on screen that they could establish an emotional relationship with. I thought I had won Ridley's agreement to that, but in fact I think he had a little reservation about that. I think he really wanted to have it both ways." (However, in an interview in Wired magazine in 2007, Ridley again states that he believes Deckard is a replicant, and says that Harrison Ford may have given up the idea of Deckard being human.)