The best cerebral sci-fi movies are so intellectually challenging because, while the reality they portray isn't yet possible, it certainly isn't implausible. Unlike fantasy where you can quickly reject the film's challenges as mere whimsy, science fiction has the ability to sink its teeth into you with the very real possibility that one day the problems the film portrays may become real. The ability to challenge the viewer in a way that's new but believable is the hallmark of the best cerebral sci-fi movies.

Blade Runner is a powerful but subtle film. In this wonderfully detailed rendering of a cyberpunk future, Rick Deckard works as a Blade Runner. The function of a Blade Runner is to identify, hunt down, and "retire" androids known as replicants. At the beginning of the film, a group of replicants have escaped an off world colony and travel to earth in search of their maker. In the process of hunting them down and killing them, Deckard meets a replicant named Rachael, who so perfectly replicates a human being that she doesn't even know that she isn't one. Battling with his own fears that he is also a replicant, Deckard falls in love with Rachael and refuses to kill her. Evidence mounts during the film that Deckard is actually a replicant and that he doesn't know it. Ultimately he kills all the off world replicants only to find himself on the run with Rachael from other Blade Runners. Blade Runner is a dark look at what makes us human. It is also a meditation on personal identity, love, and the search for meaning. While Blade Runner has been recut many times, you'll want to watch the only version that Ridley Scott ever endorsed, Blade Runner: The Final Cut. This Philip K. Dick book to film adaptation is without question one of the best cerebral sci-fi movies, if not the best.

When you watch 2001: A Space Odyssey, you're unlikely to take away everything. This film, based on one of the best Arthur C. Clarke books, is so full of mind-numbingly complex themes that it will definitely take several viewings to appreciate it all. The film meditates on human evolution in a variety of different ways. It begins with the dawn of man and the discovery of tools. During this scene we are introduced to the massive black monolith that appears at each of the film's major turning points. From there it leaps forward to man's journey into space. At each step the film questions what human beings have been, are, and will be. While most of this theme deals with human characters it also introduces an artificial intelligence that surpasses human intelligence and challenges what human beings are, or may represent what they are to become. In the final sequence of the film the characters and settings disappear and we are left with nothing more than an infant floating in a bubble in space, peering down at the earth. You'll watch this film several times before you have any concrete idea what it all means. Don't miss 2001: A Space Odyssey, one of the best cerebral sci-fi movies.

Where other films on this list pose questions that might only be possible in the worlds of science fiction, Eternal Sunshine of the Spotless Mind deals with a remarkably banal problem. Are our painful relationships worthwhile? Do we grow from the pain and loss? When we fall out of love were we ever actually in love? Instead of attempting to grapple with these questions in a regular drama, Eternal Sunshine of the Spotless Mind makes use of an imaginary technology that allows people to erase the memories of their previous lovers completely. After a passionate but tumultuous relationship, Clementine Kruczynski and Joel Barish have their memories erased. Soon after, they meet on a beach and begin a relationship with no knowledge that they had already been together for two years. When they finally discover the truth will they accept that they aren't right for each other or will they try again? The question is so simple and elegant. If you could go back and do it all over again, would you?

Moon is a slow-burning film and one of the best cerebral sci-fi movies. Sam Bell is a solitary Helium-3 miner on the moon who works a three-year contract at Sarang Station. After an accident with a harvester nearly kills him and leaves him unconscious for some time, Sam awakens in the station. He has no memory of the accident but is greeted by his AI assistant GERTY. He overhears GERTY speaking with someone on Earth and realizes that GERTY plans to hold him at Sarang Station until a rescue team arrives. Sam devises a means of escape and finds the damaged harvester. In it he finds the still unconscious body of what he soon discovers is his clone. When he brings him back to the station, the two must work quickly to discover their origin and evade capture and likely death at the hands of the rescue team. Sam's life falls apart in these final moments of the film as he realizes that his memories of his family and home are all false, and that he is only one of many clones being recycled through a mining program. Moon explores not only questions of human identity, but also the ethical problems of cloning. See it for yourself and come to your own conclusions.

Just like some of the best cerebral sci-fi movies before it, Inception asks a very simple but perplexing question. What is reality? The answer that Inception provides is much less clear-cut than the answer given by films like The Matrix. Reality is not just a single layer of illusions removed, it is layer upon layer of confusion. Inception never really answers the question fully. Instead, it poses it brilliantly in a way that leaves one questioning. The concept behind the film is that Dominick Cobb and his team can penetrate people's dreams and steal their secrets, or maybe even implant ideas in their minds. In order to return to his children and resolve the issues stemming from the death of his wife, Dominick agrees to take a job that involves implanting an idea many layers of dreams within someone's mind. The only problem is that as the film goes on Dominick's reality, just like the reality of the dream worlds being presented to us, becomes less and less clear. The film ends on the uncertainty of whether Dominick ever actually returns to his children. Watch it closely and you can't help but be gripped by this cerebral film.

The Abyss is a film that combines the best elements of the best cerebral sci-fi movies with the paranoia and fear of the Cold War. When an American nuclear submarine sinks in 1988 the Americans send a SEAL team to pair up with a private drilling rig called Deep Core in order to get ahead of Russian salvage vessels and an impending storm. As the crew of Deep Core and the SEAL team battle the claustrophobia and pressure of life at the bottom of the ocean they face off against the fear of nuclear war and an encounter with an otherworldly being. Ultimately The Abyss is a morality play about the consequences of violence and brinksmanship. While its message is less relevant after the end of the Cold War than it was in 1989, it is still one of the best cerebral sci-fi movies exploring our treatment of humanity from the perspective of aliens resembling angels and gods.

Gattaca is a bit of an unloved child. It failed to achieve box office success though it did garner a cult following soon after. Today it lacks the flash of many of the best cerebral sci-fi movies, but it remains a very powerful story. It just might take you some time to adjust to the film's incredibly polished surface. In the future of Gattaca, eugenics is common. The class system it creates is technically illegal though for all intents and purposes corporations have put it into effect. Vincent Freeman has not been eugenically selected. He is an inferior human in this future society. Yet he poses as a "valid," someone who was genetically selected, by using DNA samples from a paralyzed man. Vincent surpasses what was expected of him and advances at the company Gattaca. His goal is to travel to Titan, one of Saturn's moons. Before leaving he is caught up in a murder investigation where his "valid" brother Anton discovers his true identity. Anton decides to let Vincent go and Vincent soon learns that his DNA donor was not involved in an accident but intentionally paralyzed himself when he didn't place first in a swimming competition. The film comes to its resolution with a number of meditations on what it means to be perfect. This beautiful, polished film explores issues of eugenics and identity wonderfully.

In the future, humanity has blighted the earth. All our technology has come to nothing since the world ran out of food. In this bleak future Joseph Cooper, a former NASA pilot, raises his son and daughter along with his father-in-law. His daughter, Murphy, believes that her room is haunted by a ghost or poltergeist but Cooper explains that there's no such thing. They agree to explore the phenomena scientifically. In doing so, Cooper and Murphy discover that the "ghost" is communicating using gravity. When they interpret a message from the "ghost" as coordinates, Cooper finds the site of a NASA mission to find humanity a new home. Cooper agrees to become involved in the mission, which will travel through a black hole to visit a number of possibly inhabitable planets. However, the enormous gravitational distortion of the black hole means that the mission that will only take him a few years will leave his daughter alone for the rest of her life. I won't give away anything more because this movie deserves to be watched without being spoiled. Interstellar, which has also been deemed one of the best space travel movies and has one of the best sci-fi movie soundtracks, deals with the phenomenon of time travel and human nature as few of even the best cerebral sci-fi movies ever have.

After waking from 2 millennia of space travel at near the speed of light, three astronauts, who have only aged 18 months due to time dilation, discover their ship has crashed in a body of water on an unknown planet. The planet they discover is blighted and nearly devoid of life. In their search for food they discover an oasis where they encounter a group of primitive humans who cannot even speak. During this strange encounter a group of gorillas riding horses, carrying weapons, and speaking English attack the humans, kill some, and capture the rest. This is the world of the Planet of the Apes; one where humans have devolved and apes have surpassed them in evolution. In this world one of the astronauts, Taylor, attempts to convince the apes that he is an intelligent being. They consider him vermin and decide to castrate him. Taylor escapes after convincing only a few of the apes that humans were once intelligent. When he enters the forbidden zone that he is told humans created years ago he eventually discovers the sunken remains of the Statue of Liberty on a beach and realizes that this strange alien planet is actually the Earth after a nuclear holocaust.

Planet of the Apes deals with themes of humanity's treatment of animals, human nature, violence, and the possible consequences of the Cold War. While some of the films in the franchise have not aged well, the original Planet of the Apes is a classic and one of the best cerebral sci-fi movies.

Ex Machina, like Blade Runner, deals with problems that are not new to science fiction. It asks us to consider what makes something a human, or intelligent. Can an android be a person? This problem bookends this list. In Ex Machina, young programmer Caleb Smith wins the opportunity to perform the Turing test on Ava, a beautiful robot with artificial intelligence. The Turing test was proposed by Alan Turing and it works in the following way. If a human judge interacts with a real human, and a computer, through an interface, and the judge cannot reliably determine which is human and which is the computer, then the computer has achieved AI. In the original test the judge is not supposed to receive any visual cues, so the judge would speak to both through a computer terminal. However, Ex Machina bends the rules of this and has Caleb testing Ava in the flesh. The film spirals through a number of twists and turns as the vile, violent, and selfish nature of everyone, including Ava, becomes clear. Soon the film challenges us not to determine whether Ava is a person, but what it means to be human, and whether our vices are an essential part of our personhood. Though this film is fairly new it's still definitely one of the best cerebral sci-fi movies.