TYRELL: She's beginning to suspect, I think.
DECKARD: I don't get it, Tyrell. How can it not know what it is?
Deckard is still thinking of the replicants as things—indicated by the fact that he refers to Rachael as "it." He hasn't observed the genuine humanity of the replicants yet, and he's puzzled by the fact that Rachael seems so real.
RACHAEL: May I ask you a personal question?
RACHAEL: Have you ever retired a human by mistake?
RACHAEL: But in your position that is a risk...
TYRELL: Is this to be an empathy test?
Even though Rachael isn't a human, she's questioning Deckard's own sense of empathy. She's hinting that a failure of empathy might be at work in his own view of things, since he makes his living by killing escaped replicants, who are nearly identical to humans.
TYRELL: Rachael is an experiment, nothing more.
RACHAEL: You know that Voigt-Kampff test of yours? Did you ever take that test yourself?
Rachael is questioning Deckard's own sense of identity. How does he know he's not a replicant with implanted memories? Could he pass the test he's administered to her? Given some interpretations of the movie, Rachael's suggestion might be right on: it's subtly hinted at different moments that Deckard might actually be a replicant.
ROY: "Fiery the angels fell; deep thunder rolled around their shores; burning with the fires of Orc."
Roy identifies with the fallen angels who rebelled against God, misquoting a line from William Blake's America: a Prophecy. In this case, Roy is rebelling against the scientist who created him, Dr. Eldon Tyrell.
ROY: We're not computers, Sebastian, we're physical.
PRIS: I think, Sebastian, therefore I am.
The replicants are actually biological—they're not made from metal and wires like classic robots. They're physically human. Pris quotes René Descartes's famous line—"I think, therefore I am"—to argue that she's equal to a human since she can experience reality and contemplate it in the same way.
DECKARD: You ever tell anyone that? Your mother, Tyrell? They're implants. Those aren't your memories, they're somebody else's. They're Tyrell's niece's. Okay, bad joke, I'm sorry... No, really, I made a bad joke. Go home, you're not a Replicant... (sigh) You wanna drink? I'll get you a drink.
Deckard tells Rachael the truth—before feeling bad and claiming that he made it up. Memories form the bedrock of identity in Blade Runner, and Rachael's entire world is founded on this fictitious bedrock.
DECKARD: Tyrell really did a job on Rachael. Right down to a snapshot of a mother she never had, a daughter she never was. Replicants weren't supposed to have feelings. Neither were blade runners. What the hell was happening to me? Leon's pictures had to be as phony as Rachael's. I didn't know why a replicant would collect photos. Maybe they were like Rachael. They needed memories.
This quote is from the voiceover—which isn't included in every cut of the movie. Here, Deckard is musing on why the replicants need memories and are collecting photos—it's like they're trying to create identities in the short amount of time they still have, thereby treasuring their lives even more.
TYRELL: After all, they are emotionally inexperienced with only a few years in which to store up the experiences which you and I take for granted. If we gift them with a past... we create a cushion or pillow for their emotions and consequently we can control them better.
DECKARD: Memories. You're talking about memories.
Tyrell thinks about memories entirely as a means of control. He's indifferent to the fact that he's messing with the replicants' whole sense of reality—while at the same time giving them a basis for their human feelings.
RACHAEL: I didn't know if I could play. I remember lessons. I don't know if it's me or Tyrell's niece.
Rachael's world is in tumult after Deckard tells her that she's a replicant. She's unsure whether the things she knows about herself are really things about her or about someone else. If her entire sense of self comes from Tyrell's niece's memories, it would almost be like she doesn't have any sense of self that she can genuinely call her own.
ROY: I've seen things you people wouldn't believe. Attack ships on fire off the shoulder of Orion. I've watched c-beams glitter in the dark near the Tannhäuser Gate. All those... moments will be lost in time, like tears...in rain. Time to die.
When Roy remembers the things that have happened to him in his life, he apparently isn't remembering any false or implanted memories. He's remembering his actual experiences as a soldier, grounding himself firmly in his true identity. Poignantly, he imagines death sweeping away the memories that make up that old identity as if they were "tears in rain." These memories die with him.
DECKARD: I don't know why he saved my life. Maybe in those last moments he loved life more than he ever had before. Not just his life, anybody's life, my life. All he'd wanted were the same answers the rest of us want. Where did I come from? Where am I going? How long have I got? All I could do was sit there and watch him die.
These next two quotes are both from the voiceover versions of Blade Runner. In this one, Deckard suggests that the reason Batty refused to kill him was because his own impending death made him treasure life more—his own and everyone else's.
DECKARD: I watched him die all night. It was a long, slow thing... and he fought it all the way. He never whimpered, and he never quit. He took all the time he had, as though he loved life very much. Every second of it... even the pain. Then, he was dead.
This voiceover quote doesn't really seem to match up with the movie itself. When Batty releases the dove, this seems to be the moment at which he dies, since the whole thing is chock full of symbolism. Nevertheless, this description shows Batty using his own terrible suffering to affirm life and give it a meaning.
ROY: We've got a lot in common.
SEBASTIAN: What do you mean?
ROY: Similar problems.
PRIS: Accelerated decrepitude.
Sebastian has a disease called "Methuselah Syndrome" which involves aging prematurely. So in this way, he's similar to the replicants, who have a shorter-than-normal lifespan—a mere four years.
TYRELL: What…? What seems to be the problem?
TYRELL: Death. Well, I'm afraid that's a little out of my jurisdiction, you...
ROY: I want more life, fucker.
Tyrell says death is out of his jurisdiction because he's subject to death himself. But he's only playing humble, since he personally had the audacity to create the replicants and determine what their lifespans would be, limiting them to a mere four years. So, he's perfectly willing to play God. Speaking of which, aren't Roy's sentiments things we can all sympathize with? A lot of people would probably like to ask God (or whoever) why they have to die, too.
TYRELL: The light that burns twice as bright burns half as long, and you have burned so very very brightly, Roy. Look at you. You're the prodigal son. You're quite a prize!
ROY: I've done questionable things.
TYRELL: Also extraordinary things. Revel in your time!
ROY: Nothing the god of biomechanics wouldn't let you in heaven for.
Roy reacts to Tyrell's consolations by killing him. Tyrell didn't create Roy to "revel in his time" and celebrate the brief moment given to him—he created him to serve as a slave. Tyrell calls Roy "the prodigal son" because the prodigal son returned to his father after running away and leading sinful life—and was rewarded for returning. Part of the irony here is that Tyrell won't reward Batty and can't extend his lifespan.
ROY: I've seen things you people wouldn't believe. Attack ships on fire off the shoulder of Orion. I've watched c-beams glitter in the dark near the Tannhäuser Gate. All those ... moments will be lost in time, like tears...in rain. Time to die.
Whereas Roy had previously raged against his mortality, he now accepts it with grace. He seems overcome by wonder at his own brief life, which makes him more forgiving.
GAFF: It's too bad she won't live. But then again, who does?
Gaff implies that the replicants' time-limited lives just present a more intense version of the human predicament. We all have an expiration date.
DECKARD: "Skin jobs." That's what Bryant called Replicants. In history books he's the kind of cop who used to call black men "niggers."
This is from the voiceover version of the film. There's a bit of irony here, and it might demonstrate what some people don't like about the voiceover. While Bryant considers the replicants to be even less than second-class citizens—this makes him akin to a contemporary racist—it's important to remember that Deckard's job is to kill replicants for the crime of trying to escape from slavery. So, it's not like he's necessarily more enlightened than Bryant—at least not at the beginning.
BRYANT: Stop right where you are! You know the score, pal! You're not a cop, you're "little people."
In this society, blade runners like Deckard aren't considered to be a super-cops or anything. They're doing dirty work, considered somewhat distasteful.
TYRELL: Commerce is our goal here at Tyrell. "More human than human" is our motto.
Tyrell has created an entire class of slave laborers purely from commercial motives, which demonstrates his own wickedness. He's one of the businessman-tyrants who've helped engineer this nightmarish future version of L.A. Also, his replicants are "more human than human" in that they're biological creatures who've been engineered to function better than humans do. But is reaping profit really what makes us human?
DECKARD: The charmer's name was Gaff. I'd seen him around. Bryant must have upped him to the Blade Runner unit. That gibberish he talked was city-speak, guttertalk, a mishmash of Japanese, Spanish, German, what have you. I didn't really need a translator. I knew the lingo, every good cop did. But I wasn't going to make it easier for him.
In Blade Runner's version of L.A., the society is so linguistically and ethnically diverse that it's become a fusion of tons of cultures all intermingled at once. But the movie doesn't depict this in a positive way (compare Star Trek and its World Federation, for example). All these diverse communities seem to be trapped in a grimy, decaying underworld, without great opportunities for social advancement.
ROY: Quite an experience to live in fear, isn't it? That's what it is to be a slave.
Threatening Deckard with death, Roy tries to get him empathize with his own experience—to understand what he's had to endure throughout his entire life. Apparently, Deckard gets the message.
TYRELL: Commerce is our goal here at Tyrell. "More human than human" is our motto.
In Blade Runner's vision of the future, genetic engineers are able to toy with human life for the sake of making money, which shows that commerce has become more important than life itself, in a way. No character in the movie demonstrates that evil better than Tyrell.
ROY: Chew, if only you could see what I've seen with your eyes!
Chew created Roy's eyes—but he doesn't know what it's like to experience reality through them. Chew views these eyes as a technology he's created, whereas Roy uses them to experience reality.
SEBASTIAN: They're my friends. I make them.
Sebastian lives surrounded by bizarre, semi-human toys, which he created himself, apparently out of biological material. It's prophetic, in a way: Sebastian is like someone in the present day who only has virtual friends online or in video games but not in real life. He's a somewhat sad and sympathetic character for this reason.
DECKARD: Replicants are like any other machine. They're either a benefit or a hazard. If they're a benefit, it's not my problem.
This quote demonstrates that Deckard hasn't really seen the true humanity of the replicants yet. He still views them the same way that everyone else does, as tools and biological machines. But falling in love with Rachael and receiving mercy from Roy helps change his perspective.
RACHAEL: I'm not in the business. I am the business.
Rachael points out that she—an apparently conscious being, not particularly different from other humans—has been turned into a commodity. Even though she's alive, she's completely enslaved to the money interests that have created her.
RACHAEL: Do you like our owl?
DECKARD: It's artificial?
RACHAEL: Of course it is.
In Blade Runner's version of 2019, many animals have become extinct—hence, the ones we encounter in the movie, from Tyrell's owl to Zhora's snake, are all artificial, the animal equivalents of replicants. In Philip K. Dick's novel Do Android's Dream of Electric Sheep?, owls are the first species to go extinct.
TYRELL: I'm surprised you didn't come here sooner.
ROY: It's not an easy thing to meet your maker.
TYRELL: What can he do for you?
ROY: Can the maker repair what he makes?
Tyrell can't repair Roy and extend his lifespan to a normal human length: he's a deeply flawed creator. In this case, his creation (Roy) rebels against him and kills him in retribution. The replicant technology created by Tyrell has stopped being technology and has gone out of his control—the replicants have transcended their slave-like status and demonstrated that they're real people, more or less.