Ridley Scott’s Blade Runner was a game changer in the world of science-fiction. In 1982, the same year that kid-friendly films like E.T. were released conveying the adventures of a cuddly extra-terrestrial, Scott’s vision of the near-future was introducing thought-provoking questions about the advancement of artificial intelligence, humankind’s desire to play God, and what constituted being “human” with the rise of genetic engineering.

Set in 2019 Los Angeles after the degradation of Earth from a nuclear war, resources are scarce and anyone wealthy enough to do so ventures off-world. Off-world planets are colonized by replicants, synthetic beings created for the purpose of slave labor and dangerous activities unfit for humans. After a replicant revolt, they’re forbidden from returning to Earth, but a few escape in a shuttle intent on making a better life for themselves. Deckard is the “Blade Runner” sent to “retire” them, along the way discovering more about his own humanity as he hunts those considered “more human than human.” Here are five things that are scientifically accurate about the film — and five that make no sense.

SCIENTIFICALLY ACCURATE: SYNTHETIC ORGAN PRODUCTION

In Blade Runner, Roy Batty pays a visit to the scientist behind the replicant’s synthetic eyes. This man deals in eyes, but the rest of replicant’s organs are synthetic as well. Today, the technology and science exists to generate organs in a lab that gives hope to those on lists for organ transplants.

Referred to as “bioartificial organ manufacturing technologies,” organ substitutes (or artificial organs) will soon be made from cells designed to adapt to the tissue around them and become part and parcel with the individual who needs them. Stem cell research has been instrumental in 3D-printing bio-organs today, such as the thyroid gland.

MAKES NO SENSE: A NUCLEAR HOLOCAUST

Blade Runner takes place in 2019, and the world has been made into an over-crowded, gritty, dystopian environment. In Philip K Dick’s book Do Android’s Dream of Electric Sheep?, this is due to the “World War Terminus,” a nuclear war that left the world almost uninhabitable. If you’re wealthy, you move off-world.

The film never exactly explains why there was a nuclear war, or who started it. As it stands with the state of nuclear weaponry in the world, 90% of which is owned by the United States and Russia, both countries are aware that a nuclear holocaust would make the world uninhabitable due to ensuing firestorms, nuclear winters, and radioactive fallout. Ergo, how would all of this advanced technology from the Tyrell Corp even exist?

SCIENTIFICALLY ACCURATE: ARTIFICIAL INTELLIGENCE

While we’re nowhere near able to make a replicant as advanced as Roy Batty and those seen in the film, the fields of robotics has made significant strides in recent years. Sophia, the social robot programmed with hundreds of different algorithms and 50 facial expressions does a good job of “replicating” a human’s appearance enough to interact with her comfortably.

Of course, we as a society have to be ready for such advancements. Even with artificial organ transplants, at what point is a human still a human? What will rights and civil liberties look like as we make advancements in the technology of artificial intelligence to the point that, as the Tyrell Corp says, there are individuals among us that “look more human than human?”

MAKES NO SENSE: LIVING OFF-WORLD

After the nuclear war that devastated the planet, humans had two choices: either scramble for resources on their home planet, or look to outer space for other livable conditions on a new planet. Thanks to the Tyrell Corp and its replicants, other planets can be colonized with minimal danger to humans, allowing them to live off world.

How far away are they from Earth? How far can humans get in this near future? The film takes place in 2019, and we have only just been able to land a chemical-rocket without ditching it out to see on its de-burn into our atmosphere. And is there a lottery to get off-world or is it simply a matter of being able to afford the space travel?

SCIENTIFICALLY ACCURATE: A KILL SWITCH

Because of the possibility of replicants going rogue, Tyrell Corp put in a limited lifespan (four years) to act as a sort of “kill switch.” Some replicants had displayed erratic behavior around that time, particularly where emotional overload was concerned. Their actions could be dangerous to humans since they were so much stronger and faster, so it also served to make humans more comfortable with the replicant presence.

Today, genetic engineers that have been working with T-cell therapy have already considered this. Since they work with manipulating T-cells outside the body that are then put into a human, there is a chance they’ll eventually go rogue or reject their new environment. They could become cancerous and start an attack on the human body.

MAKES NO SENSE: ATTACK SHIPS OFF THE SHOULDER OF ORION

Roy Batty, a Nexus-6 replicant designed to be a perfect soldier for Earth’s military, has a poetic monologue towards the end of the film. He explains to Deckard that he’s seen things he can’t possibly imagine, like “attack ships off the shoulder of Orion” and something about “glittering C-beams”.

This is fantastic for world-building purposes and painting a vivid picture of the sort of interstellar battles Roy Batty has been in during his short four-year life span, but it doesn’t explain how as a society, after a nuclear holocaust, we would have the technology at all to build space ships (not chemical-rockets) capable of engaging in skirmishes with…aliens? What exactly were they fighting out there in the off-world colonies?

SCIENTIFICALLY ACCURATE: THE VOIGHT-KAMPFF TEST

In Blade Runner, the fictional Voight-Kampff test is used to identify if an individual is a replicant or a human. It’s designed to trigger emotions in the subject, which replicants wouldn’t be able to have. Through a series of questions and images, it monitors the subject’s physiological response, such as reaction time and pupillary movement.

Neuroscientists today use a test that’s very similar. A database called the International Affective Picture System contains emotionally disturbing pictures and some neutral ones, and is used to measure a person’s emotional response by their reactions. These days it can also be coupled with brain scans, something that wasn’t around when Philip K. Dick wrote the novel on which Blade Runner is based.

MAKES NO SENSE: REPLICANT AUTONOMY

Unlike the android Ash of Ridley Scott’s Alien, replicants like Roy Batty are more biological in nature. When you cut them open, you won’t see wires, motors, and metal, but soft, genetically-engineered tissue. That being said, there’s no mention of what “powers” a replicant.

They appear human, but don’t require “sleep” or “food” or “social contact” to exist. They are efficient slave laborers, soldiers, and pleasure bots precisely because they’re more effective at their tasks than humans ,who would require time away from their work. Even our most advanced robots today can’t handle certain physical environments, never mind be nimble, store power, and move autonomously for days on end.

SCIENTIFICALLY ACCURATE: MEMORY IMPLANTATION

One of the biggest ways a replicant differs from a human is their memories. As they were never “born” and had no childhood, but emerge as fully-formed adult humans in appearance when they’re constructed, they have to have memories implanted. This is a way for them to have an “anchor” on their emotions, which would override their systems otherwise.

Today, cognition researchers use memory implantation as a technique in relation to cognitive psychology. They make subjects believe a memory happened to them that never actually did. These implanted memories prove how easy it is to distort a human’s memory of a past event, casting doubt over the repressed therapy techniques of digging for memories that may not be valid. At that point, would a human and a replicant be so different if they both believed their memories to be true?

MAKES NO SENSE: AI KILLING HUMANS

The robot-doomsday scenario is a mainstay in the sci-fi genre. In films like Terminator and I, Robot, the artificially intelligent beings turn on their human creators and threaten to wipe out humankind. It always boils down to the robot/AI/replicant either becoming “self aware” and wanting to preserve itself over humans who wish to destroy it, or deciding humans should be destroyed because they’re inefficient/a danger to themselves (think Ultron in Avengers).

However, the crucial issue with the scenario is that while AI is still programmed by humans, AI doesn’t think like humans. Humans can learn from very few examples of failure, but AI must replicate scenarios over and over to learn patterns not to repeat. In this way, they are far from developing consciousness. We should be more afraid of how humans would use AI, than how it would use itself.