The simulation hypothesis proposes that all of reality, including the earth and the universe, is in fact an artificial simulation, most likely a computer simulation.
Some versions rely on the development of a simulated reality, a proposed technology that would seem realistic enough to convince its inhabitants the simulation was real. The hypothesis has been a central plot device of many science fiction stories and films.

There is a long philosophical and scientific history to the underlying thesis that reality is an illusion. This skeptical hypothesis can be traced back to antiquity; for example, to the "Butterfly Dream" of Zhuangzi, or the Indian philosophy of Maya.Simulation Hyposthesis There is a long philosophical and scientific history to the underlying thesis that reality is an illusion. This skeptical hypothesis can be traced back to antiquity; for example, to the "Butterfly Dream" of Zhuangzi, or the Indian philosophy of Maya.Simulation Hyposthesis There is a long philosophical and scientific history to the underlying thesis that reality is an illusion. This skeptical hypothesis can be traced back to antiquity; for example, to the "Butterfly Dream" of Zhuangzi, or the Indian philosophy of Maya.Simulation Hyposthesis There is a long philosophical and scientific history to the underlying thesis that reality is an illusion. This skeptical hypothesis can be traced back to antiquity; for example, to the "Butterfly Dream" of Zhuangzi, or the Indian philosophy of Maya.Simulation Hyposthesis Many works of science fiction as well as some forecasts by serious technologists and futurologists predict that enormous amounts of computing power will be available in the future. Let us suppose for a moment that these predictions are correct. One thing that later generations might do with their super-powerful computers is run detailed simulations of their forebears or of people like their forebears. Because their computers would be so powerful, they could run a great many such simulations. Suppose that these simulated people are conscious (as they would be if the simulations were sufficiently fine-grained and if a certain quite widely accepted position in the philosophy of mind is correct). Then it could be the case that the vast majority of minds like ours do not belong to the original race but rather to people simulated by the advanced descendants of an original race. It is then possible to argue that, if this were the case, we would be rational to think that we are likely among the simulated minds rather than among the original biological ones. Therefore, if we don't think that we are currently living in a computer simulation, we are not entitled to believe that we will have descendants who will run lots of such simulations of their forebears. Simulation Hypothesis Many works of science fiction as well as some forecasts by serious technologists and futurologists predict that enormous amounts of computing power will be available in the future. Let us suppose for a moment that these predictions are correct. One thing that later generations might do with their super-powerful computers is run detailed simulations of their forebears or of people like their forebears. Because their computers would be so powerful, they could run a great many such simulations. Suppose that these simulated people are conscious (as they would be if the simulations were sufficiently fine-grained and if a certain quite widely accepted position in the philosophy of mind is correct). Then it could be the case that the vast majority of minds like ours do not belong to the original race but rather to people simulated by the advanced descendants of an original race. It is then possible to argue that, if this were the case, we would be rational to think that we are likely among the simulated minds rather than among the original biological ones. Therefore, if we don't think that we are currently living in a computer simulation, we are not entitled to believe that we will have descendants who will run lots of such simulations of their forebears.

Reality is the sum or aggregate of all that is real or existent, and as opposed to that which is merely imaginary. The term is also used to refer to the ontological status of things, indicating their existence. In physical terms, reality is the totality of the universe, known and unknown. Philosophical questions about the nature of reality or existence or being are considered under the rubric of ontology, which is a major branch of metaphysics in the Western philosophical tradition. Ontological questions also feature in diverse branches of philosophy, including the philosophy of science, philosophy of religion, philosophy of mathematics, and philosophical logic. These include questions about whether only physical objects are real (i.e., Physicalism), whether reality is fundamentally immaterial (e.g., Idealism), whether hypothetical unobservable entities posited by scientific theories exist, whether God exists, whether numbers and other abstract objects exist, and whether possible worlds exist. Simulated reality is the hypothesis that reality could be simulated—for example by quantum computer simulation—to a degree indistinguishable from "true" reality. It could contain conscious minds which may or may not be fully aware that they are living inside a simulation. This is quite different from the current, technologically achievable concept of virtual reality. Virtual reality is easily distinguished from the experience of actuality; participants are never in doubt about the nature of what they experience. Simulated reality, by contrast, would be hard or impossible to separate from "true" reality. There has been much debate over this topic, ranging from philosophical discourse to practical applications in computing. Dreaming / A dream could be considered a type of simulation capable of fooling someone who is asleep. As a result, the "dream hypothesis" cannot be ruled out, although it has been argued that common sense and considerations of simplicity rule against it. One of the first philosophers to question the distinction between reality and dreams was Zhuangzi, a Chinese philosopher from the 4th century BC. He phrased the problem as the well-known "Butterfly Dream," which went as follows: Once Zhuangzi dreamt he was a butterfly, a butterfly flitting and fluttering around, happy with himself and doing as he pleased. He didn't know he was Zhuangzi. Suddenly he woke up and there he was, solid and unmistakable Zhuangzi. But he didn't know if he was Zhuangzi who had dreamt he was a butterfly or a butterfly dreaming he was Zhuangzi. Between Zhuangzi and a butterfly there must be some distinction! This is called the Transformation of Things. (2, tr. Burton Watson 1968:49) The philosophical underpinnings of this argument are also brought up by Descartes, who was one of the first Western philosophers to do so. In Meditations on First Philosophy, he states "... there are no certain indications by which we may clearly distinguish wakefulness from sleep", and goes on to conclude that "It is possible that I am dreaming right now and that all of my perceptions are false". Chalmers (2003) discusses the dream hypothesis and notes that this comes in two distinct forms: Both the dream argument and the simulation hypothesis can be regarded as skeptical hypotheses; however in raising these doubts, just as Descartes noted that his own thinking led him to be convinced of his own existence, the existence of the argument itself is testament to the possibility of its own truth. Another state of mind in which some argue an individual's perceptions have no physical basis in the real world is called psychosis though psychosis may have a physical basis in the real world and explanations vary. The dream hypothesis is also used to develop other philosophical concepts, such as Valberg's personal horizon: what this world would be internal to if this were all a dream. Nested simulations / The existence of simulated reality is unprovable in any concrete sense: any "evidence" that is directly observed could be another simulation itself. In other words, there is an infinite regress problem with the argument. Even if we are a simulated reality, there is no way to be sure the beings running the simulation are not themselves a simulation and the operators of that simulation are not a simulation. "Recursive simulation involves a simulation or an entity in the simulation, creating another instance of the same simulation, running it and using its results" (Pooch and Sullivan 2000).

In 2003, philosopher Nick Bostrom proposed a trilemma that he called "the simulation argument". Despite the name, Bostrom's "simulation argument" does not directly argue that we live in a simulation; instead, Bostrom's trilemma argues that one of three unlikely-seeming propositions is almost certainly true: The trilemma points out that a technologically mature "posthuman" civilization would have enormous computing power; if even a tiny percentage of them were to run "ancestor simulations" (that is, "high-fidelity" simulations of ancestral life that would be indistinguishable from reality to the simulated ancestor), the total number of simulated ancestors, or "Sims", in the universe (or multiverse, if it exists) would greatly exceed the total number of actual ancestors. Bostrom goes on to use a type of anthropic reasoning to claim that, if the third proposition is the one of those three that is true, and almost all people with our kind of experiences live in simulations, then we are almost certainly living in a simulation. Bostrom claims his argument goes beyond the classical ancient "skeptical hypothesis", claiming that "...we have interesting empirical reasons to believe that a certain disjunctive claim about the world is true", the third of the three disjunctive propositions being that we are almost certainly living in a simulation. Thus, Bostrom, and writers in agreement with Bostrom such as David Chalmers, argue there might be empirical reasons for the "simulation hypothesis", and that therefore the simulation hypothesis is not a skeptical hypothesis but rather a "metaphysical hypothesis". Bostrom states he personally sees no strong argument for which of the three trilemma propositions is the true one: "If (1) is true, then we will almost certainly go extinct before reaching posthumanity. If (2) is true, then there must be a strong convergence among the courses of advanced civilizations so that virtually none contains any individuals who desire to run ancestor-simulations and are free to do so. If (3) is true, then we almost certainly live in a simulation. In the dark forest of our current ignorance, it seems sensible to apportion one's credence roughly evenly between (1), (2), and (3)... I note that people who hear about the simulation argument often react by saying, 'Yes, I accept the argument, and it is obvious that it is possibility #n that obtains.' But different people pick a different n. Some think it obvious that (1) is true, others that (2) is true, yet others that (3) is true." As a corollary to the trilemma, Bostrom states that "Unless we are now living in a simulation, our descendants will almost certainly never run an ancestor-simulation." Criticism of Bostrom's anthropic reasoning Bostrom argues that, if "the fraction of all people with our kind of experiences that are living in a simulation is very close to one", then it follows that we probably live in a simulation. Some philosophers disagree, proposing that perhaps "Sims" do not have conscious experiences the same way that unsimulated humans do, or that it can otherwise be self-evident to a human that they are a human rather than a Sim. Philosopher Barry Dainton modifies Bostrom's trilemma by substituting "neural ancestor simulations" (ranging from literal brains in a vat, to far-future humans with induced high-fidelity hallucinations that they are their own distant ancestors) for Bostrom's "ancestor simulations", on the grounds that every philosophical school of thought can agree that sufficiently high-tech neural ancestor simulation experiences would be indistinguishable from non-simulated experiences. Even if high-fidelity computer Sims are never conscious, Dainton's reasoning leads to the following conclusion: either the fraction of human-level civilizations that reach a posthuman stage and are able and willing to run large numbers of neural ancestor simulations is close to zero, or we are in some kind of (possibly neural) ancestor simulation. Some scholars categorically reject or are uninterested in anthropic reasoning, dismissing it as "merely philosophical", unfalsifiable, or inherently unscientific. Some critics reject the block universe view of time that Bostrom implicitly accepts and propose that we could be in the first generation, such that all the simulated people that will one day be created don't yet exist. The cosmologist Sean M. Carroll argues that the simulation hypothesis leads to a contradiction: if a civilization is capable of performing simulations, then it will likely perform many simulations, which implies that we are most likely at the lowest level of simulation (from which point one's impression will be that it is impossible to perform a simulation), which contradicts the arguer's assumption that advanced civilizations can most likely perform simulations.

Let’s delve into the top reasons why we may be living in a simulation after all:
1. Pixels, Resolution, Virtual and Augmented Reality One of the main arguments that Musk makes is that a more advanced civilization will have games that are of very high resolution — so high that we would be unable to distinguish between the “real” world and a “simulated one”. Today we are already seeing with Virtual Reality that “full immersion” is possible. Anyone who has played a convincing VR game will realize that it’s possible to forget about the real world and “believe” the world you are seeing is real. As a great example, I was playing a prototype of a Ping Pong VR game last year (built by Free Range Games), and even though it wasn’t realistic resolution, I lost myself and thought I was playing ping pong for real. So much so that I set the paddle on the ping pong “table” and leaned against the table. Of course it was a VR table so it didn’t really exist — I ended up dropping the paddle (actually the Vive controller) onto the floor. As I leaned into the “table” I almost fell over before realizing that there was no table. In other words, to quote from the Matrix, there is no spoon.

2. An Open World and the Illusion of Infinite Possibilities. Early video games were very linearly structured, such as space invaders or Pac-Man. There was a limited set of “motions” that were allowable using some “input” control, and there were specific objective as part of the each level, and you progressed linearly through the levels. As video games evolved and 3d models of a “world” became commonplace, video games took an evolutionary leap. It seemed from the player’s perspective that you could move around and do anything. Examples of open world video games range from GTA (Grand Theft Auto) and WOW (World of Warcraft), or the Sims, which simulated life and eventually Virtual Worlds like Second Life. Of course the idea that he world is infinite and that we can do “anything” inside the world is a carefully crafted illusion. Game designers know that’s not true. Using 3D modeling we can have a world that is generated and looks infinite but is really a set of maps and rules. In any game, no matter how “open” it appears, there are underlying tasks, or quests, or accomplishments, which are mapped out by the game designers. Is it possible that we have a similar illusion of “open-ness” in life?

3. The Collapse of the Probability Wave, Future Selves, and Parallel Universes
In Quantum physics one of the most intriguing ideas is the probability matrix, which is an interpretation of how subatomic particles can exhibit properties of both a wave and a solid particle at the same time. At the level of an electron or a photon, the wave is interpreted as a set of probabilities of where the particle might be at any given time. When we observe a particular possibility, then the probability wave is said to “collapse” and we see a single particle in a particular location. Some interpreters have taken this to the macro level to say that there are a set of probabilities in which we exist both in the present and in the future. Which of the possible paths do we follow? There isn’t a good explanation; how the probability wave collapses is one of the biggest mysteries in Quantum Physics. The best answer physicists have come up with is that consciousness somehow determines the collapse. Physicist Fred Alan Wolf, for example, says that information from these possible futures is coming to us in the present and that we send out an “offer wave” into the future, which is interacting with the “offer waves” coming from the future to the present. Which possible future we navigate to depends on which choices we make, and how these two waves super-pose on each other (or cancel each other out).

These are just some of the reasons why we may be living in a Video Game after all, the Great Simulation. I haven’t even gotten into some of the more esoteric or psychological reasons (which would take a whole book unto itself). As computer science and artificial intelligence rapidly advance their capabilities, it may be possible to create a simulated world that looks and feels as real as our own. Video games, which started out with simple rules about what can be done and simple 2d worlds, have advanced rapidly into a MMORPG (massive multi-player online role playing games) with millions of players interacting in a simulated world. As computer technology advances, the chances of creating a billion player plus simulated world like our own is rapidly approaching. Moreover, Quantum Physics gives us a description of the univere (or multiple universes) that doesn’t make sense from the perspective of an “objective reality” but requires observation by some consciousness. These sometimes incredible findings defy common sense, unless we are living inside a video game rather than a physical reality and consciousness is the equivalent to us “logging into” the system. Eastern traditions, particularly Buddhist traditions, have long contended that we are living in world of illusion, and that we go through multiple lives trying to work out our individual quests, all of which are stored beyond the “rendered world”. There is a giant system that not only stores this but creates new situations for us to get our “achievements”. Sure sounds like a Video Game to me. All of these areas, Computer Science/Artificial Intelligence, Quantum Physics, and Eastern spiritual traditions point to one likely scenario: That we are living inside a very sophisticated Video Game, which I call The Great Simulation. Like all simulations, our world may only be real while the “simulation” is running. This reminds me of a quote from the British intellectual, Havelock Ellis, about dreams. He said:“Dreams are real while they last. Can we say any more of life?” Can we indeed??