Simulated reality describes a hypothetical environment that, although experienced as real, is actually a highly detailed simulation of reality.
Unlike the currently technologically achievable concept of virtual reality, which is easily distinguished from the experience of "real" reality, a simulated reality would be very hard, if not impossible, to tell apart from "real" reality. Hyperreality describes postmodern ideas regarding the perceptions of reality which in some ways parallel this concept.
The modern conceptual version of simulated reality involves a thought experiment along the lines of imagining that the person experiencing the simulated reality is somehow interfacing with a computer of considerable power that is regulating the rules of the simulation, and provides the subject with sensory input. A deeper thought experiment may even assume that the subject experiencing the simulation is itself simulated within the simulation, and may have no physical existence at all outside of the simulation.
This is a precise modernization of the Eastern supposition that "we are just the dreams of a god", in which the god can be considered a primitive anthropomorphism of the simulating mechanism, for example a computer running a physics model.
One practical, one philosophical, and one ethical question arise immediately:
- is it, even in principle, possible to tell whether we are in a simulated reality or a real one?
- is there any difference between the two?
- how should we behave if we knew that we were living in a simulated reality?
Simulated people in simulated reality
Several people have pointed out that if a human brain is analyzed in sufficient detail, the mechanism of that brain might be electronically simulated. The result would behave as an electronic duplicate of the original human brain, as occurs in mind transfer. Whether the speed is similar to the normal speed of a brain would affect how it could interact with the real world. Gathering enough detail is neither possible nor practical, at present in the early 21st century. Science fiction authors have noted various difficulties which such a being may encounter, such as its existence being legally recognized, the right to own property, and the relationships with the original and other duplicates of itself.
Is this a simulated reality?
The simulation argument, claimed by the philosopher Nick Bostrom, investigates the possibility that we may be living in a simulation. The argument attempts to prove the disjunction of three hypotheses (that is, that at least one of the following three propositions must be true), that:
either
His argument uses the premise that given sufficiently advanced technology, it is possible to simulate entire inhabitated planets or even larger habitats or even entire universes as quantum simulations in time/space pockets, including all the people on them, on a computer, and that simulated people can be fully conscious, and are as much persons as non-simulated people are.
If we then assume that the human race could reach such a technological level without destroying themselves in the process (i.e. we deny the first hypothesis); and that once we reached such a level we would still be interested in history, the past, and our ancestors, and that there would be no legal or moral strictures on running such simulations (we deny the second hypothesis) - then
- it is likely that we would run a very large number of so-called ancestor simulations;
- and that, by the same line of reasoning, many of these simulations would in turn run other sub-simulations, and so on;
- and that given the fact that right now it is impossible to tell whether we are living in one of the vast number of simulations or the original ancestor universe, the likelihood is that the former is true.
Assumptions as to whether the human race (or another intelligent species) could reach such a technological level without destroying themselves depend greatly on the value of the Drake equation, which gives the number of intelligent technological species communicating via radio in a galaxy at any given point in time. The expanded equation looks to the number of posthuman civilizations that ever would exist in any given universe. If the average for all universes, real or simulated, is greater than or equal to one such civilization existing in each universe's entire history, then odds are rather overwhelmingly in favor of the proposition that the average such civilization is living in a simulation, assuming that such simulated universes are possible and such civilizations would want to run such simulations.
A number of criticisms of the simulation argument exist.
The disjunctive logic of Bostrum's "Simulation Argument" fails to recognize a fourth hypothesis:
No life, in any universe, has evolved sufficiently to be able to create the technology required to support such a simulation.
As of 2006, the computational requirements for Molecular dynamics are such that it takes several months of computing time on the world's fastest computers to simulate 1/10th of one second of the folding of a single protein molecule.
Some consider the Simulation Argument to be little more than a modern, perhaps more plausible, rehashing of the idea put forth in the middle ages, most notably by René Descartes - that perceived existence is the result of the workings of a deceiving god or an evil demon. Hilary Putnam postulated a "brain-in-a-vat" scenario.
Others see the proposition itself as being rather metaphysical, having little to no real life applicability since the claim is essentially unprovable in any concrete sense - any "evidence" that is directly observed could be another simulation itself. This is akin to an infinite regress problem with the argument. Even if we are a simulated reality, there is no way to be sure the people running the simulation are not themselves a simulation, and the operators of that simulation are not a simulation, ad infinitum. Given the premises of the simulation argument, any reality, even one running a simulation, has no better or worse chances of being a simulation than any other.
Another criticism is that reality is only what is perceived as reality. Even if this is a "simulation", it is still the only "Reality" we have ever known, and we have no example of a non simulated reality to compare it to, so this is still, in a sense, "reality" as we understand it. Reality simply becomes defined down to a narrower scope, with a bigger super-reality "above" it.
Another criticism that can be made is that the argument relies on probability when not all possible outcomes are known. The conclusion that we might be living in a simulated universe makes the assumption "there can be large number of simulated universes and one physical universe" is not necessarily true. There are other possibilities and hence probability cannot be applied to only a subset of the outcomes.
The standard rebuttal for this appears to be that if we use the rules of our own apparent reality, then we know that there can be a large number of simulated universes, because we're capable of producing that with only a slight improvement in our technology... while if we stipulate that the simulating universe's rules might not be the same as ours, then we are already admitting that we are not the top level reality. The criticism depends on bringing our own reality's logic into question in the first place.
Either way, even if this is a simulated reality, our actions in it still have the same consequences for us as they would in a "real" reality. it is questionable as to whether there is any real difference for us if we are in a simulation or not. This reality can still affect us and is as dangerous as any physical realm would be.
Birth In A Simulated Reality
Another question raised about simulated reality is what would happen if a human is 'born' in simulated reality. This does not mean the physical process of creating a human in reality, but rather interfacing an infant with the simulation. The simulation would not have to be as realistic, or even close, to reality, because the human will grow to accept it. If the human subject has no memories of 'actual' reality, he will assume the simulation is true, considering the subject has nothing to compare it with.
Also, what would happen if the human, which grew up to accept the simulated reality, were brought out of the simulation?
Theological models of a simulated reality
Several theological models feature a simulated reality as a key concept. These include:
The Dreamtime, a very important concept in Aboriginal mythology .
Simulated reality in fiction
Simulated reality is a theme that pre-dates science fiction. In Medieval and Renaissance religious theatre, the concept of the world as a theater is frequent. Works, early and contemporary.
