Here are 3 good reasons reasons why:
- Memory implants: In the original Blade Runner movie, we see that replicants are given implanted memories to help them blend in with human society. In Blade Runner 2049, we learn that these implanted memories can be so vivid and realistic that the replicants themselves can't always distinguish them from real memories. Deckard is shown to have vivid memories of a child, which turn out to be implanted. This strongly suggests that he is a replicant.
- DNA: In a scene in Blade Runner 2049, Deckard's DNA is tested and found to be identical to the child that he remembers. This is a strong indication that his memories were implanted and that he is, in fact, a replicant.
- The film's themes: Blade Runner 2049 explores themes of identity, memory, and what it means to be human. The revelation that Deckard is a replicant adds another layer to these themes and raises questions about what it means to be alive and conscious.
“The fact that it’s a question is what’s important. The puzzle of Blade Runner, one of the many reasons it’s the classic it is, is that the chasing for authenticity is both baked into the narrative of the story and the meta-narrative of the film that there is no authentic answer to that question.
Which just meant that telling the further story, that had to be baked into the story as well, that everyone who watches it has that question of which version should I watch, what does that mean, and the answer is you don’t get to know.
Generally American audiences are very uncomfortable with that level of irresolution. Blade Runner challenges that and it’s not just an American favorite, it’s a global favorite.”
Ultimately, we consider the director's vision the key to understanding this question. While the original script writer asserts Deckard is human, director Ridley Scott put in the whole Unicorn riddle to make it clear Deckard was indeed a replicant. 2049, as a film, dances around this point.
