The attributes of humanity--the quality or state of being human--have always been claimed exclusively by the homo sapiens. Human beings delight in distancing themselves from animals, robots, machines, or other beings without that amicable trait called true emotion. However, recent modern texts such as Philip K. Dick's novel Do Androids Dream of Electric Sheep and its subsequent film adaptation Blade Runner have called these notions into question with their portrayal of fictional androids, or replicants. These so-called "humanoid robots"(13) are treated as inferior species and used for slave labor on planetary colonies. Are they capable of humane behavior, and if so what constitutes humanity? The key differences between novel and adaptation show that Androids believes that there are certain human qualities that simply cannot be manufactured, while Blade Runner turns the concept around and implies that humanity can be acquired, that the true nature of humanity might not lie simply with one's biological characteristics.

The first important difference between Androids and Blade Runner is the way they show how the androids or replicants interact with each other. In the novel, androids are portrayed as ruthless and mercenary toward each other, seemingly incapable of "empathy"(26). Dick explains that "the emphatic faculty probably [requires] an unimpaired group instinct"(26) and that "predators"(27) like the androids could not survive with such an instinct because it blurs "the boundaries between hunter and victim"(26). Therefore, according to the novel, the androids do not look out for each other because of a built-in survival mechanism. At several turns in the novel one can see this mechanism at work. Rachael Rosen ultimately has no qualms about helping Rick hunt down her own kind, even a Nexus-6 type who looks exactly like her, because "androids have no loyalty to one another and I know that that goddamn Pris Stratton will destroy me and occupy my place"(167). One can see Rachel's survival instinct overpowering her initial anxiety over Pris's appearance. Later, when Rick buys Luba Luft an art book, Luba says resentfully: "An android would never have done that"(117). Another example is when the androids seek refuge with J.R. Isidore and Roy Baty muses that if Isidore were an android, "he'd turn us in about ten tomorrow morning"(144). Even with the group that had escaped from Mars together, Dick does not describe them as interacting with an affection that would come with old friendship. When Roy and Irmgard are reunited with Pris, he smiles a "crooked, tuneless smile" and Irmgard asks "How are you"(134), the kind of question one would expect from a passing acquaintance, not from a long lost friend. Isidore points out that it is "as if a peculiar and malign abstractness pervaded their mental processes"(137). The androids' biological inability to truly care deeply about one another explains why they will never be able to understand the empathy of Mercerism; Roy's attempt at an android equivalent of Mercerism never succeeds, and the androids remain lonely.

By contrast, Blade Runner treats the subject completely differently. It endows the replicants with fiery primitive passions that the human beings in the film--Rick, Tyrell, J.F. Sebastian--seem to lack, a passion that can be inferred from their unconventional clothing, their abrupt movements, their strong appearance. More importantly, they seem to harbor genuine affection towards one another, or at least an affection that the film has articulated more clearly. The Roy of the film gets choked up when he tells Pris that the other replicants have died, whereas the Roy of the novel "[delivers] the news as if, perversely, it pleased him to be telling this"(136). When Leon witnesses Rick killing Zhora, he tries to kill Rick in revenge; later Roy would break one of Rick's fingers for each of his dead friends. Finally, when Roy finds Zhora's dead body, the sight jars him so that he feels compelled to touch his lips to her bloody body. During this relatively subdued moment of the film the soundtrack is silent, leaving Roy to his tender mourning, lending the moment a quiet sincerity. Afterwards, language deserts Roy and he can only express his sorrow with the primitive howl. The film does a much better job of articulating Roy's sorrow, whereas in the novel Dick provides allows only one line when Irmgard dies: "Roy Baty, in the other room, let out a cry of anguish"(197). The violent passions in these replicants, particularly those that are stirred up in response to a friend's death, contrast sharply with the novel's portrayal of the androids as stoic, apathetic beings.

Another difference between the two kinds of humanoid robots is their connection to the past, to memories: the androids have a tenuous connection to the past; the replicants, more human-like, cling to it stubbornly. Although Androids's Rachael Rosen does recollect her past, the memory that the Association implanted for her seems deliberately sterilized of any association with humanity. Eldon Rosen explains that she had grown up on a spaceship until the age of fourteen, "living off its tape library and what the nine other crew members . . . knew about earth"(46). Firstly, she grew up at an isolated location, separated from the majority of humanity; secondly, the description of her education seems cold and bookish because she did not learn from nurturing parents but from tapes and crew members, people who could hardly provide her the emotional warmth of a family. In contrast, Blade Runner's Rachael has memories of a childhood that would sound familiar to any human being, a childhood represented by faded black and white photographs of the happy past, a childhood of summer adventures and youthful transgressions. When Rick informs her that those memories are implants, her anguish is palpable and real. Her emotions here are underscored by the lingering close up shot, the low-key lighting, and the melancholy piano notes. And yet, she does not let go of her past. She clings to it as any human being would. Instinctively, she gravitates toward the piano that her mother had taught her how to play: she still feels that connection despite what Rick has told her. Even Leon, the most brutish of the replicants, seems to long for or treasure that connection between mother and child: it is only when Dave Holden asks him about his mother that he finally loses control. Later as a fugitive, Leon attempts to go back to his room to retrieve his "precious photographs," mementos from the past. The androids in the novel do not have such tender moments as the humans disallow them any biological or mental aspirations towards humanity. Even when the androids do remember, their memories are seldom happy. One gets the feeling from the film that the replicants' humanistic memories and the way they cling to them are essential to their humanity.

Actual human behavior in both the novel and film serve the artists' different creative intentions. To emphasize the uniqueness of human beings, Dick creates Mercerism, a spiritual cult that the androids cannot decipher or try to emulate. In the end, they resort to mudslinging and tabloid journalism exposés, but Mercerism has the final victory. Just when Isidore's world begins to fall apart, Mercer mysteriously appears to reassure him thus: "From [the androids'] standpoint Buster Friendly's disclosure was convincing. They will have trouble understanding why nothing has changed"(189). Mercerism continues despite the androids' best attempt at sabotage. Mercerism, like humanity, takes on an aura of mystery, and androids are biologically incapable of learning either's secrets. In contrast, by omitting Mercerism from the adaptation, director Ridley Scott deprives the humans in his story of a major tool with which they can separate themselves from the replicants. Animals are another means with which Dick distinguishes human beings from androids. In a world where animals are considered sacrosanct, in a tier above the androids in the social hierarchy, androids are "unable to keep [animals] alive. Animals require an environment of warmth to flourish"(114). Not only do the androids lack that human quality--warmth--that is required to care for animals, the cruelty various androids in the story display towards animals emphasizes their lack of humanity. Pris and Irmgard pluck the legs off a spider for their amusement, much to Isidore's horror; Rachael pushes Rick's goat off the roof without a second thought. The sanctity of animals is another theme that Blade Runner omits in its adaptation, and it accomplishes the same objective as the omission of Mercerism. By taking away not one, but two themes in the novel that serve to distinguish human qualities from mere android existence, Scott strips humanity of its auras of uniqueness and elusiveness, thus facilitating the film's claims that androids are capable of acquiring true human emotions despite their biological makeup.

Turning from the portrayal of androids and replicants in general, one should compare each text's specific treatment of one of the central characters, Rachael. In the end, the spurious humanity of Androids's Rachael dies out in her exiting act of consummate cruelty, while the film's Rachael reaffirms her humanity--despite her biological constraints--with Rick. In the beginning of the novel, Rick administers the Voigt-Kampff test to Rachael. For the first few questions she reacts appropriately, but in the end Rick makes the correct assessment: that while Rachael's response are correct, they are simulated. This scene works as a microcosm for Rachael's character as portrayed by Dick. In the scene where Rachael sleeps with Rick, she almost has Rick--and the reader--convinced that she feels genuine human feelings. She tells Rick that she loves him, and in his inebriated state Rick imagines that Rachael "had become cheerful and certainly as human as any girl he had known"(172). There are even moments in this scene during which Rachael becomes obviously despondent over the fact that she cannot bear children like real woman do, or the fact that androids like herself only have lifespans of two years. However, Dick uses subtle linguistic hints to neutralize Rachael's sexuality and to remind the reader that she really is a piece of machinery, incapable of reproduction. She is described as "childlike," with odd proportions and the stance of a "wary hunter"(164). Her legs have "a neutral, nonsexual quality"(164) and her loins are "pale" and "cold"(171). Despite Rachael's brief moments of self-pity and concern for Rick, in the morning she seems herself again as she coolly reveals to Rick the true purpose of her visit. Pretty soon she has all her attention on Buster Friendly's show as she is assured that Rick will not able to continue as a bounty hunter. Her final act, that of killing Rick's goat, is one that is considered of consummate inhumanity in the universe of the novel.

Compared to Rachael Rosen, the Rachael Tyrell of Blade Runner progresses in an opposite direction, becoming more and more human as the movie continues. When Rachael first appears in the film, she wears clothes that are stiff black--the color of death, or in the replicants' case, of lack of life--and her movements are awkward, wary. But contact with Rick immediately brings out human responses in her. Rick challenges her on the point of her false memories, but later helps her rediscover her humanity when he treats her like a human woman rather than like a replicant. Eventually, Rachael lets down her hair and sheds her awkward clothing. Her profile becomes softer as the camera zooms in on her at the piano, and at that moment she does become "more human than humans."

The film plays with the character of Roy Baty in a similar fashion, endowing him with humane characteristics he did not possess in the novel. The novel describes Roy as the most brutish and mechanical, and less human, of the androids. He has "flat, Mongolian features which gave him a brutal look"(134), "oblique"(134) eyes. There is a moment when Isidore looks at Roy and sees "briefly a frame of metal, a platform of pullies and circuits and batteries and turrets and gears"(139). His presence creates discomfort because he does not often display the human traits that his female companions at times do, and he has no regard whatsoever for Isidore as a human being. With Isidore standing right next to him, Roy suggests to his fellow androids that they kill him and move somewhere else. Even so, Dick allows Roy one moment of tenderness when Rick kills Irmgard.

The film, however, does with Roy what it does with Rachael. Despite retaining the original Roy's brutal characteristics, the Roy in Blade Runner accomplishes what he could not accomplish in the novel: he finally understands what it means to be human, what it means to empathize. Roy is one of the most lively characters in the film, and his life and his love for that life seem to exceed what the other humans in the film have. When he visits Tyrell, his presence--however ominous--infuses the pale, candle-lit, morbid room with color, youth, and life. Like Rachael, he seems capable of feeling genuine affection towards his fellow androids and even eventually toward a human being. With his grief over his friends' deaths working him into a rage, Roy becomes psychopathic and seems bent on killing Rick. However, when he sees Rick hanging onto a beam, struggling to survive, he arrives at a decision that will ultimately make him human. He decides to save Rick. And at that moment, the low angle shot shows a Roy standing tall, a Roy who has become larger and more good than the sum of his entire previous existence. The dove that rests in Roy's arms symbolizes his new found peace. Fittingly, as his send-off Roy recites an impromptu poem that eulogizes a too-brief life--"All those moments will be lost in time like tears in the rain"--and the gesture is so utterly human that Rick stares at him in awe. In the book, Roy spends his entire existence trying to create a drug that will help androids recreate the experience of Mercerism and its empathy; in the film, Roy accomplishes what he could not in the novel simply by discovering his own humanity and making the choice to save Rick.