That’s the thing, though. Any physical object could be scanned for. (Even non-magnetic stuff.) With the technology levels displayed in the movie, MRI stuff should be childs play, and no need for a VK.
Full spectrum medical scanners were shown in Star Trek: The Motion Picture being used on the Ilea replacement-droid, so the concept was out there in Hollywood land.
Right, either they are A: humans (more or less) or they are B: androids who can dip their hands in boiling water with no ill effects. They can’t be both. Anyone whose skin was so tough as to easily withstand boiling water could be detectable without any psychological testing.
I don’t think the movie gives us enough information to know what kinds of scans could be performed or whether this would be easier/cheaper than administering the VK test.
I concede the point.
R.U.R. Rossum’s Universal Robots. By Karel Capek in 1921. Everybody remembers that the play invented the word robot, but almost nobody knows what it was about (including me until I read it recently).
The robots that the play is about are artificial humans, made from a protoplasm-like substance and anatomically simplified to be able to easily manufacture. They are incapable of being told apart from humans from mere appearance, but at first they do not have emotions or even feel pain. In fact, they have a limited lifespan as well and no reproductive ability. Over the course of the play they are given more and more humanity. They are taught to use weapons and replace all the world’s soldiers. They then rebel and kill off every human in the world, except one. However, the secret of their protoplasm is also destroyed so they’re now screwed. In an epilogue, it turns out that the last model robots have the ability to feel love for one another and that magically gives them the power to have babies. Adam and Eve - yes, literally with those names - will repopulate the world.
I don’t remember if any biography talks about Dick reading the play (or seeing one of its many revivals) but the coincidences are thick on the ground, even more so in the movie version which discards most of Dick’s boring obsession with animals. The play’s moral is that humanness isn’t about physiology but emotions. If you look at it that way, the replicants are as human as the humans. Or as not-human as the humans, which I think is more Dick’s view of the world.
For that matter, Deckard is briefed on the escaped replicants and shown production-line pictures of each. How hard would it have been to give those same pics to the Tyrell corporate security people, who could’ve spotted recent-hire Leon instantly?
Seems to me to be one of those plot holes that’s not a plot hole. Tyrell might know full well who and where each of the replicants are, but for whatever reason consider it convenient or less messy to have a captured and re-programmed replicant believe he’s a cop and go off murdering the others, rather than having their human staff go and do the work. “You’ve done a man’s job, sir!”
No, they’re biological androids. The movie’s “Voight-Kampff test” scene is meant to draw attention this by suggesting a crucial difference (empathy) in the Replicant’s psychological makeup. When Leon realizes what the test is and that he is failing it, he kills the Tyrell employee administering it to him.
If anyone disagrees with my assessment, feel free to tell me.
I concur with Astral Rejection’s take, though I’d add that possibly there are passionate humans still around - they’ve just all migrated to the offworld colonies. The bummed-out losers who couldn’t summon the energy and pass the physicals remain on Earth, wallowing in its rain-soaked smog-choked decay.
Minor correction: Leon kills “Holden,” another cop/Blade Runner.
When Bryant has Gaff fetch Deckard and bring him in, Deckard tells Bryant something along the line sof “Give it to Holden, he’s good.”
Bryant: “I did. He can breathe okay, as long as no one unplugs him.”
ETA: added relevant bit from Theopane’s post.
I really doubt that Tyrell Corp. would be inclined to let a replicant whom they employ, Leon, shoot and nearly kill an LAPD detective, Holden, on the corporate premises.
I prefer the term “Artificial Person” myself. 
That didn’t happen in the movie I saw.
I agree with most of your comments on the film. In particulasr at the start i felt Leon could well respond this way if autistic. Autistics are humans - is the film suggesting some autistic behaviour can be deemed inhuman, preventing people recognising they are simply a minority part of a normal distribution curve?
Right. Any creature that can stick his hand into boiling water like that has to have different DNA.
Which asks the question: why not just test the replicants with a drop of boiling water?
Yeah, that scene always bugged the hell out of me.
Read the book way back when, and saw the movie when it first came out … here’s how I explain the Replicants: they aren’t clones exactly, they are assembled from biological “parts”, grown in vats separately. The organs and bones, etc., are mass produced by specialists. Combining the parts results in a being with no parent except perhaps the original cell donations upon which the genetic code for the vat “meat” is based.
Since we don’t know what progress will be made in medical and genetic science, we can’t presume that humans, having perhaps had medical procedures involving replaced organs or novel cell or virus therapy, can be reliable differentiated from Replicants. Maybe the tests to identify manufactured pseudo-humans give false positives for transplant patients with “grown” organs or limbs.
I wouldn’t be too sure that human tissue couldn’t be resistant to freezing temps, like the liquid nitrogen that Batty reached into, or to the boiling water Priss grabbed the egg from.
Again, futurist medical treatments may involve genetic changes in human patients that mimic the altered flesh or tissue of the Androids.
The movie mostly features replicants. What actual humans do we see who don’t display expected emotion? Vague references to jadedness aren’t good enough. Who exactly doesn’t emote in exactly what way? Most of the humans we see are hard boiled cops, extras who are given about as much chance to display emotion as any extra is, and Tyrell. They may not be emoting much, but in what way would you expect them to?
Tyrell had some replicant in him, mostly in his eyes.
There are humans with only human DNA who are insensitive to pain. This recent New York Times piece on the subject actually opens with a story about a girl reaching into a pot of boiling water.
Seems like it would be pretty easy for a replicant to feign pain in this situation, provided they can sense changes in temperature. They apparently cannot bluff their way through the VK test, though. Even Rachel was identified as a replicant through the VK test, it just took longer than usual.