A replicant is a bioengineered or biorobotic being created in the film Blade Runner (1982). The Nexus series—genetically designed by the Tyrell Corporation—are virtually identical to an adult human, but have superior strength, agility, and variable intelligence depending on the model. Because of their physical similarity to humans, a replicant must be detected by its lack of emotional responses and empathy to questions posed in a Voight-Kampff test. A derogatory term for a replicant is "skin-job." (Note: This term reappears in the reimagined Battlestar Galactica in derogatory reference to Humanoid Cylons – who could also be considered a type of replicant.)
Philip K. Dick's novel Do Androids Dream of Electric Sheep? which inspired Blade Runner used the term android (andy), but director Ridley Scott wanted a new term that did not have preconceptions. As David Peoples was rewriting the screenplay he consulted his daughter who was involved in microbiology and biochemistry. She suggested the term "replicating" which is the process of duplicating cells for cloning. From that, one of them (each would later recall it was the other) came up with replicant and it was inserted into Hampton Fancher's screenplay.
Replicants in the film 
Replicants became illegal on Earth after a bloody mutiny by Nexus-6s off-world. The Tyrell Corp./Rosen Assoc. discovered that the longer a Nexus-6 lived the more life-experience it gained. With these memories they often developed their own emotional reflexes, and the longer they lived the more independent and unstable their personalities became. So, Tyrell added a "fail-safe device" to Nexus-6 models: a built-in four-year lifespan to prevent them from developing their own "emotional responses." This was especially necessary for Mental-A models whose intellectual capacity at least matched those of their genetic designers.
However, Tyrell later tells Roy that the preset life-span is inherently dependent on Nexus-6 biology. Noting that "the candle that burns twice as bright burns half as long", Tyrell explains that the reason Nexus-6 replicants do not live longer is not due to some sort of kill switch, but because they physically cannot—the result of the superhuman capabilities engineered into them. Roy suggests several means of extending his lifespan (demonstrating that he possesses at least equal knowledge to that of his creator about his physical construction), but Tyrell reveals that he already tried each of these suggestions, failing in every attempt.
Special police units (Blade Runners) are sent to investigate, test and ultimately "retire" (kill) replicants found on Earth. Because the escaped replicants are the latest Nexus-6 generation Deckard had no experience with them, and wasn't even sure if the Voight-Kampff test would work.
Escaped replicants (all Nexus-6 Physical-A models):
- Roy Batty (played by Rutger Hauer) is a self-sufficient combat model for the colonization defence program. (Mental-A)
- Pris Stratton (played by Daryl Hannah) is a prostitute referred to as a "basic pleasure" model for military personnel. (Mental-B)
- Zhora Salome/Luba Luft (played by Joanna Cassidy) was retrained for political homicide, operating in a "kick murder squad." (Mental-B)
- Leon Kowalski/Max Polokov (played by Brion James) is a combat model or loader for nuclear fission. (Mental-C)
- Hodge was killed in an electrical field at the Tyrell Corporation.
- Mary/Irmgard Batty, the 6th replicant. Actress Stacey Nelkin was cast in the part of Mary but the character was cut from the film early on in principal photography due to budget constraints. This created a plot hole and speculation among fans as to whether Deckard was the 6th replicant with new memories. However, in the 2007 Final Cut, Captain Bryant's dialog was altered, so he now mentions two Replicants killed by the electric field, rather than just one as in the 1982 U.S. theatrical version. In the original workprint version, Bryant also mentions two Replicants killed.
- Rachael (played by Sean Young) is a prototype Nexus-6 with implanted memories from Eldon Tyrell's niece.
Tyrell developed Rachael as an experimental replicant with false memory implants, so she would think she was human. Tyrell said that these memories would act as a "pillow" to cushion her developing emotions. As a result, Rachael behaved in a far more "human" manner than any previous replicant. Normal replicants aren't very empathetic or "human" in character, and are emotionally unstable, because over 4 years, they develop the same experiences humans develop over decades. Thus, Leon who is only two years old is somewhat immature; while four year old Roy Batty who is feeling the effects of his impending death shows a range of emotions. Roy appears capable of love, guilt, sorrow, and empathy (although these emotions confuse him to a degree). According to Deckard, a normal replicant can usually be discovered using the Voight-Kampff test after being given about 20-30 questions, cross-referenced. However, Rachael answered over 100 questions before Deckard realized she was a replicant. In particular, the question that finally revealed she was a replicant involved a reaction to people "eating raw oyster and boiled dog": it is implied that Rachael simply didn't have enough life-experience to know that this wasn't considered socially permissible.
The theatrical cut's voiceover ending said that as an experimental replicant Rachael didn't have the pre-determined four-year lifespan, but the Director's Cut left that ambiguous.
In Do Androids Dream of Electric Sheep? the Rosen Corporation simply did not know how to manufacture an android capable of living longer than four years.
Was Deckard a replicant? 
Blade Runner's dark paranoid atmosphere – and multiple versions of the film – adds fuel to the speculation and debate over this issue.
In the book, Rick Deckard (the main character) is at one point tricked into following an android, who believes himself to be a police officer, to a faked police station. Deckard then escapes and "retires" some androids there before returning to his own police station. However, Deckard takes the Voight-Kampff test and it fails to indicate that he is an android.
Harrison Ford, who played Deckard in the film, has said that he did not think Deckard was a replicant, and also states he and the director had discussions that ended in the agreement that the character was human. However, according to several interviews with director Ridley Scott, Deckard is indeed a replicant. He collects photographs, seen crowding over his piano, yet has no obvious family, beyond a reference to his ex-wife (who called him cold fish). In a scene where Deckard talks with Rachael, their eyes both appear to shine in the way indicative of Replicants.[original research?]
Furthermore in the Director's Cut police officer Gaff (played by Edward James Olmos) leaves Rick Deckard an origami Unicorn a day after Rick dreamed of one. Just before Deckard finds the unicorn, Gaff says to him in passing, "It's too bad she [Rachael] won't live...then again, who does?". A unicorn can also be seen briefly in a scene in J. F. Sebastian's home, amongst scattered toys (to the right of a sleeping Sebastian, while Pris snoops around his equipment). Unicorns also appear several times in the dream sequences of the director's cut, and as it is explained in the film; Rachael's memories are known by her creators, e.g. the memory Rachael has of the spiders (as explained to her by Deckard in the movie). That Gaff is leaving origami unicorns at Deckard's house, implies that Gaff is aware of the content of Deckard's unicorn dream.
The dream may not be uniquely Deckard's, as the unicorn does appear in J.F. Sebastian's house. As J.F. co-designed the Nexus-6 (and other) replicants, one could take the opinion that the unicorn dreams are a "personal touch" added to some or all Nexus-6's (and above) "brains." Since we are not privy to the dreams of the other replicants, this is unknown - however it does add weight to the argument. From this one could also speculate that Gaff himself is a replicant and may share in the same imbedded memory.[original research?]
Paul Sammon, author of Future Noir: The Making of Blade Runner, has suggested in interviews that Deckard may be a Nexus-7, a next-generation replicant who possesses no superhuman strength or intelligence, but brain implants that complete the human illusion. This view is shared by Ridley Scott. Sammon also suggests that Nexus-7 replicants may not have a preset lifespan (i.e., they could be immortal). If so, this may suggest that Rachael is also a Nexus-7.
Further, Sammon stated that Ridley Scott thought it would be far more provocative to imply that Deckard was a replicant, without giving a definitive answer. This ties back into the central theme of "what is it to be human?" What is important is not so much whether Deckard is a replicant or not, but that very possibility and uncertainty further blurs the line between humans and replicants.
In a related comment, when Scott was asked about the possibility of a Blade Runner sequel in October 2012, he said, "It's not a rumor—it's happening. With Harrison Ford? I don't know yet. Is he too old? Well, he was a Nexus-6 so we don't know how long he can live. And that's all I'm going to say at this stage."
Organic or mechanical? 
Although the press kit released to the media for the film explicitly defined a replicant as, "A genetically engineered creature composed entirely of organic substance", a question commonly posed is the physical make-up of the replicants themselves. In the opening crawl of the film, replicants are said to be the result of "advanced robot evolution." The crawl also states that they were created by "genetic engineers." Characters mention that they have eyes and brains like humans, and they are seen to bleed when injured (although they can take a lot more damage than humans can). The film explicitly shows that at least their eyes are created and stored separately, so there must be some "assembly" required. An alternative explanation could be that they are cyborgs, having both human and machine parts. That the (apparently) only way of telling a replicant from a human is to ask a series of questions and analyse emotional response would suggest they are entirely, or almost entirely, organic. If they had any significant level of non-organic parts than something as simple as an x-ray scan would show them not to be human (unless their creators designed the non-organic parts to have almost exactly the same structure and density as the organic components they were replacing, which would be both infeasible and highly improbable but not completely out of the question).
The original novel makes mention of the biological components of the androids, but also alludes to the mechanical aspects commonly found in other material relating to robots.
In May 2012, Ridley Scott confirmed that the replicants were biological in nature, and contrasted them to the androids in the Alien series. "Roy Batty was an evolved... He wasn't an engine. If I cut him open, there wasn't metal, he was grown... and then within twenty years you get the first bill not passed in the Senate where they applied for replication of animals, sheep and goats and cattle and animals and they turned it down, but if you can do that, then you can do human beings. If you go deeper into it and say 'Yeah, but if you are going to grow a human being, does he start that big and I've got to see him through everything?' I don't want to answer the question, because of course he does... Ash in Alien had nothing to do with Roy Batty, because Roy Batty is more humanoid, whereas Ash was more metal".
- Interview with David Proples in Sacrificial Sheep: The Novel vs. the Film. Enhancement Archive of Blade Runner Ultimate Collector's Edition
- "Blade Runner riddle solved". BBC News. 2000-07-09. Retrieved 2007-08-02.
- "Blade Runner Interview with Ridley Scott and Sean Young".
- Sammon, Paul (2002) BRmovie.com — Interview with Paul M. Sammon, sections 13 and 17
- Sammon, Paul (2002) BRmovie.com — Interview with Paul M. Sammon, sections 13
- Sullivan, Kevin P. (October 12, 2012), "Ridley Scott Gives 'Prometheus 2' And 'Blade Runner 2' Updates", MTV Movies Blog, retrieved October 13, 2012
- BRmovie.com: BR FAQ: Blade Runner Terminology
- Weintraub, Steve 'Frosty' (31 May 2012). "Ridley Scott Talks PROMETHEUS, Viral Advertising, TRIPOLI, the BLADE RUNNER Sequel, PROMETHEUS Sequels, More". Retrieved 2 June 2012.
Further reading 
- Glaser, Horst Albert and Rossbach, Sabine: The Artificial Human, Frankfurt/M., Bern, New York 2011 "The Artificial Human"
- BRmovie.com - The Blade Runner FAQ – What are Replicants?