Usuario:J. Manolo G. P./Taller/9

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No tiene equipos en las grandes ligas profesionales estadounidenses, pero si una gran representación a nivel universitario con los Mountaineers de la Universidad de Virginia Occidental, y también los Thundering Herd de la Universidad Marshall, ambos compitiendo en la División I de la NCAA.

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Realidad simulada

(This line of thought is continued in Platonic simulation theories).

Computability of physics

A decisive refutation of any claim that our reality is computer-simulated would be the discovery of some uncomputable physics, because if reality is doing something no computer can do, it cannot be a computer simulation. In fact, known physics is held to be computable.^[1]

The objection could be made that the simulation does not have to run in "real time".^[2] But it misses an important point: the shortfall is not linear, rather it is a matter of performing an infinite number of computational steps in a finite time.^[3] This objection does not apply if the hypothetical simulation is being run on a hypercomputer, a machine more powerful than a Turing machine.^[4] Unfortunately, there is no way of working out if computers running a simulation are capable of doing things that computers in the simulation cannot do. No one has shown that the laws of physics inside a simulation and those outside it have to be the same, and simulations of different physical laws have been constructed.^[5] The problem now is that there is no evidence that can conceivably be produced to show that the universe is not any kind of computer, making the Simulation Hypothesis unfalsifiable and therefore scientifically unacceptable, at least by Popperian standards.^[6]

CantGoTu Environments

The concept of a CantGoTu Environment takes the ideas embedded in the Diagonal Argument of George Cantor, the Undecidability theorems of Kurt Gödel, and the limits of computability highlighted by Alan Turing, and applies them to Virtual Reality environments. The argument is set out in The Fabric of Reality (1997) by David Deutsch, and runs thus:

Imagine a computer built to render every possible Virtual Reality. Suppose all possible environments produced by this generator can be laid out sequentially, as Environment 1, Environment 2, etc. Take time slices through each of these of equal duration. (Deutsch specifies one minute, but this could, in principle be anything, e.g. Planck time.) Now construct a new environment as follows. In the first time-period, generate in the environment anything which is different from Environment 1, and in the second time period, anything different from Environment 2, and so on. This new environment cannot be found in the sequential layout of environments specified earlier, as it differs from all possible environments by what happens in one particular time-slice. Hence this means that no such universal VR generator can be created, and there are environments which effectively can never be rendered by any means (since there are infinitely many).^[7]

[Yet if all possible virtual reality initial conditions have been simulated and still it is possible to create a reality that plays out differently to those already created (despite starting at an initial condition common to one of those already in existence) then that extra environment must obey slightly different cause and effect laws of reality, or else it would simply play out in the same way as one of those already simulated. This implies that the argument by Deutsch is only valid if the laws that govern each virtual reality may be different: i.e. they would have to allow inconsistencies such as objects suddenly disappearing or appearing out of nowhere for every time an environment transitions from one time slot to another. If instead one simply assumes that there are infinitely many possible initial conditions, since they vary by infinitesimally small amounts, then (even if all follow the same laws) there will be infinitely many possible virtual realities that could be generated, which leads to the same conclusion as Deutsch.]

However, later on in the book, Deutsch goes on to argue for a very strong version of the Turing principle, namely: "It is possible to build a virtual reality generator whose repertoire includes every physically possible environment."

However, in order to include every physically possible environment, the computer would have to be able to include a full simulation of the environment containing itself. Even so, a computer running a simulation need not have to run every possible physical moment to be plausible to its inhabitants.

Computational load

Virtual people

A 2007, 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.^[8]^[9] To simulate an entire galaxy would require more computing power than can presently be envisioned, assuming that no shortcuts are taken when simulating areas that nobody is observing.

In answer to this objection, Bostrom calculated that simulating the brain functions of all humans who have ever lived would require roughly 10³³ to 10³⁶ calculations.^[10] He further calculated that a planet-sized computer built using known nanotechnological methods would perform about 10⁴² calculations per second — and a planet-sized computer is not inherently impossible to build, (although the speed of light could severely constrain the speed at which its subprocessors share data). In any case, a simulation need not compute every single molecular event that occurs inside it; it may only process events that its participants can actively perceive. This is particularly the case if the simulation contained only a handful of people; far less processing power would be needed to make them believe they were in a "world" much larger than was actually the case.

Brain-computer interface

Some ^[¿quién?] have argued that a dream is a reality being simulated for certain parts of the dreamer's brain by other parts of the dreamer's brain — possibly showing that a 'computer' less powerful than a whole human brain can simulate oft-believable realities for the senses. Similar arguments would apply to vivid recollections, imaginings, and especially hallucinations. However, all of these things are usually less vivid and do not have to consistently obey the laws of physics, which our world does and which constraint presumably requires more computational power. (Another point some^[¿quién?] have made about hallucinations is that the hallucination cannot be interacted with in a rich, vivid way requiring simulation of multiple senses, possibly because the brain knows it does not have the computing power to support such interaction.)

Additionally, it's possible that the parts of our brains that question the validity of a situation are impaired when we sleep. The believability of a simulation is an important influence on the results it generates.

Validity of the arguments

In any case, it is perhaps erroneous to apply our current sense of feasibility to projects undertaken in an outer reality, where resources and physical laws may be very different. It also assumes designers would need to simulate reality beyond our natural senses.

Also, a simulated reality need not run in real time. The inhabitants of a simulated universe would have no way of knowing that one day of subjective time actually required much longer to calculate in their host computer, or vice-versa. Isaac Asimov pushed the limits of this by claiming^{[cita requerida]} that, unbeknownst to the inhabitants, the simulation could even run backwards, or in pieces on different computers, or with a million generations of monks working weekends on abacuses — all without the simulation missing a beat 'in simulation time'.

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, ad infinitum. Given the premises of the simulation argument, any reality, even one running a simulation, has no better or worse a chance of being a simulation than any other.

Occam's razor

It has been noted that there is no definitive way to tell whether one is in a simulation. It is generally the case that any number of hypotheses can explain the same evidence.^[11] This situation often prompts the use of a heuristic rule called Occam's razor, which prefers simpler explanations over more complex ones, and is often implicated in skeptical criticisms of far-fetched hypotheses.^[12]^[13]^[14]

Since it is a heuristic rule, and not a natural law, it is not an infallible guide as to what is ultimately the truth, but only what is usually best to believe, all other things being equal. If we assume Occam's Razor applies, then it would tell us to reject simulated reality as being too complex, in favor of reality being what it appears to be.^[15]

Scientific and technological approaches

Software Bugs

A computed simulation may have voids or other errors that manifest inside. A simple example of this, when the "hall of mirrors effect" occurs in the first person shooter Doom, the game attempts to display "nothing" and, obviously fails in its attempt to do so. If a void can be found and tested, and if the observers survive its discovery, then it may reveal the underlying computational substrate. However, lapses in physical law could be attributed to other explanations, for instance inherent instability in the nature of reality.

In fact, bugs could be very common. An interesting question is whether knowledge of bugs or loopholes in a sufficiently powerful simulation are instantly erased the minute they are observed since presumably all thoughts and experiences in a simulated world could be carefully monitored and altered. This would, however, require enormous processing capability in order to simultaneously monitor billions of people at once. Of course, if this is the case we would never be able to act on discovery of bugs. In fact, any simulation significantly determined to protect its existence could erase any proof that it was a simulation whenever it arose, provided it had the enormous capacity necessary to do so.

To take this argument to an even greater extreme, a sufficiently powerful simulation could make its inhabitants think that erasing proof of its existence is difficult. This would mean that the computer actually has an easy time of erasing glitches, but we all think that changing reality requires great power.

Hidden messages or "Easter eggs"

The simulation may contain secret messages or exits, placed there by the designer, or by other inhabitants who have solved the riddle, in the way that computer games and other media sometimes do. People have already spent considerable effort searching for patterns or messages within the endless decimal places of the fundamental constants such as e and pi. In Carl Sagan's science fiction novel Contact, Sagan contemplates the possibility of finding a signature embedded in pi (in its base-11 expansion) by the creators of the universe.

However, such messages have not been made public if they have been found, and the argument relies on the messages being truthful. As usual, other hypotheses could explain the same evidence. In any case, if such constants are in fact infinite, then at some point an apparently meaningful message will appear in them (this is known as the infinite monkey theorem), not necessarily because it was placed there.

The Easter Egg Theory also assumes that a simulation would want to inform its inhabitants of its real nature; it may not. Otherwise, if we consider that the human race will eventually be capable of creating intelligent programs (i.e. machines) living inside a virtual subspace of our "real" world, then an interesting question would be to define whether or not we will be capable of suppressing from our sentient robots their capability of knowing their artificial nature (see Do Androids Dream of Electric Sheep?).

Processing power

A computer simulation would be limited to the processing power of its host computer, and so there may be aspects of the simulation that are not computed at a fine-grained (e.g. subatomic) level. This might show up as a limitation on the accuracy of information that can be obtained in particle physics.

However, this argument, like many others, assumes that accurate judgments about the simulating computer can be made from within the simulation. If we are being simulated, we might be misled about the nature of computers.

Taken one step further, the "fine grained" elements of our world could themselves be simulated since we never see the sub-atomic particles due to our inherent physical limitations. In order to see such particles we rely on other instruments which appear to magnify or translate that information into a format our limited senses are able to view: computer print out, lens of a microscope, etc. Therefore, we essentially take on faith that they're an accurate portrayal of the fine grained world which appears to exist in a realm beyond our natural senses. Assuming the sub-atomic could also be simulated then the processing power required to generate a realistic world would be greatly reduced.

Digital physics and cellular automata

In theoretical physics, digital physics holds the basic premise that the entire history of our universe is computable in some sense. The hypothesis was pioneered in Konrad Zuse's book Rechnender Raum (translated by MIT into English as Calculating Space, 1970), which focuses on cellular automata. Juergen Schmidhuber suggested that the universe could be a Turing machine, because there is a very short program that outputs all possible programmes in an asymptotically optimal way. Other proponents include Edward Fredkin, Stephen Wolfram, and Nobel laureate Gerard 't Hooft. They hold that the apparently probabilistic nature of quantum physics is not incompatible with the notion of computability. A quantum version of digital physics has recently been proposed by Seth Lloyd. None of these suggestions has been developed into a workable physical theory.

It can be argued that the use of continua in physics constitutes a possible argument against the simulation of a physical universe. Removing the real numbers and uncountable infinities from physics would counter some of the objections noted above, and at least make computer simulation a possibility. However, digital physics must overcome these objections. For instance, cellular automata would appear to be a poor model for the non-locality of quantum mechanics.

Other issues

Non-player characters or "bots"

Some of the people in a simulated reality may be automatons, philosophical zombies, or 'bots' added to the simulation to make it more realistic or interesting or challenging. Indeed, it is conceivable that every person other than oneself is a bot. Bostrom called this a "me-simulation", in which oneself is the only sovereign lifeform, or at least the only inhabitant who entered the simulation from outside.

Bostrom further elaborated on the idea of bots:

In addition to ancestor-simulations, one may also consider the possibility of more selective simulations that include only a small group of humans or a single individual. The rest of humanity would then be zombies or "shadow-people" – humans simulated only at a level sufficient for the fully simulated people not to notice anything suspicious. It is not clear how much [computationally] cheaper shadow-people would be to simulate than real people. It is not even obvious that it is possible for an entity to behave indistinguishably from a real human and yet lack conscious experience.^[10]

The idea of "zombies" has a well known corollary in the video game industry where computer generated characters are known as Non-Player Characters ("NPCs"). The term 'bots' is short for 'robots'. The usage originated as the name given to the simple AI opponents of modern video games.===Subjective time=== A brain-computer interface simulated reality may be required to progress at a rate that is near realtime; that is, time within it may be required to pass at approximately the same rate as the outer reality which contains it. This might be the case because the players are interacting with the simulation using brains which still reside in the outer reality. Therefore, if the simulation were to run faster or slower, those brains could notice because they were not contained within it.

It is possible that time passes slower or quicker for brains in a dream state (i.e., in a brain-computer interface trance); however, the point is that they still function at a finite, biological speed, and the simulation must track with them. Unless those interacting with the simulation are augmented and capable of processing information at the same rate as the simulation itself.

A virtual-people or emigration simulated reality, on the other hand, need not. This is because its inhabitants are using the simulation's own physics in order to experience, think, and react. If the simulation were slowed down or sped up, so also would the inhabitants' own senses, brains, and muscles, as well as every other molecule inside. The inhabitants would perceive no change in the passage of time, simply because their method of measuring time is dependent on the cosmic clock that they are seeking to measure. (They could perform the measurement only if they had some access to data from the outer reality.)

For that matter, they could not even detect whether the simulation had been completely halted: a pause in the simulation would pause every life and mind within it. When the simulation was later resumed, the inhabitants would continue exactly as they were before the pause, completely unaware that (for example) their cosmos had been paused and archived for a billion years before being resumed by a completely different director. A simulation could also be created with its inhabitants already possessing memories as though they had already lived part of their lives before; said inhabitants would not be able to tell the difference unless informed of it by the simulation. (Compare with the five minute hypothesis and Last Thursdayism).

One practical implication of this is that a virtual-people or a hybrid simulation does not require a computer powerful enough to model its entire cosmos at full speed. Per the Turing completeness theorem, a simulation can progress at whatever speed its host computer can manage; it would be constrained by available memory but not by computation rate.

Recursive simulations

A simulated reality could contain a computer that is running a simulated reality. The 'parent' simulator would be simulating all of the atoms of the computer, atoms which happen to be calculating a 'child' simulation. By way of illustration: imagine that a human is playing a game of The Sims in which one of the player's Sims (simulated people) is playing a computer game in the game. Alternatively, imagine a Java Runtime Environment running a virtual computer on a "real-world" computer that itself is located within a simulation.

This recursion could continue to infinitely many levels — a simulation containing a computer running a simulation containing a computer running a simulation and so on. The recursion is subject only to one constraint: each 'nested' simulation must be:

smaller than its parent reality, because its own memory must be a subset of the parent's;

...and must be at least one of the following:

slower than its parent reality, because its own calculations must be a subset of the parent's; or
less complex than its parent reality, via simplifications of processes that are computationally intensive in the parent reality; or
less complete than its parent reality, via approximations of objects that nobody is observing.

The latter is the basis of the idea that quantum uncertainties are circumstantial evidence that our own reality is a simulation. However, this assumes that there is a finite limitation somewhere in the chain. Assuming an infinite number of simulations within simulations, there need not be any noticeable difference between any of the subsets.

Religious parallels

Archivo:SimulatedReality MormonPlanOfSalvation.jpg

The Mormon plan of salvation, an emigration type of simulated reality

This line of thought is paralleled in some religions. Mormonism in particular features a "Plan of Salvation" which teaches that humans are spiritual beings who are visiting the Earth in a temporary limited form, for the purpose of learning certain lessons which only mortality can teach:

"Training for eventual salvation began for each person at the time of his spirit birth. Following a long period of pre-existent, probationary schooling, this earth was created to be a place where the hosts of spirits who keep their first estate might come, receive mortal bodies, and undergo further testing and trials. {Moses 4:1-4, Abraham 3:22-28}
At death the eternal spirits go to a spirit sphere to gain further experience and then finally they come up in the resurrection, stand before the judgment bar, and are awarded their places in the kingdoms of glory which are prepared. {Alma 40; 41; Doctrine and Covenants 76.} (McConkie 1966)

However, Mormonism does not support the theory that the world is a simulation.

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 theater is frequent. Works, early and contemporary, include:

Literature

This is an alphabetical list (though chronological may be better), pay attention where you add your entries

Accelerando (2005) by Charles Stross
Breakfast of Champions (1973) by Kurt Vonnegut Jr. In this novel, Vonnegut's character Kilgore Trout, an amateur Sci-fi writer, writes a story that mocks individualism by suggesting that there is only one human man and one God, and the rest of humanity are robots, made to test the man's reactions; hence, a kind of simulated reality.
The Circular Ruins by Jorge Luis Borges (not simulated reality, but subjective idealism/solipsism).
The Cookie Monster (2004), by Vernor Vinge
Darwinia (1998) by Robert Charles Wilson
Diaspora (1997) by Greg Egan
Discourse on Method (1637) by René Descartes
The Electric Ant- short story by Philip K. Dick.
Eternity (novel) (1988) by Greg Bear, in particular his introduction of the Taylor algorithms as a means of determining the simulated nature of an artificial environment.
Feersum Endjinn (1994) by Iain M. Banks (his later novel, The Algebraist, posits a religion that believes our universe is virtual).
Flight: a Quantum Fiction novel (1995) by Vanna Bonta, posits that our universe is a virtual metaverse whereby collective and individual consciousness creates reality on the quantum level.
Forever Free (1999) by Joe Haldeman
The Futurological Congress (1971) by Stanislaw Lem
Get Real: A Philosophical Adventure in Virtual Reality (1998) by Philip Zhai
The Girl Who Was Plugged In (1974) by James Tiptree Jr.
Glasshouse (2006) by Charles Stross
Idlewild by Nick Sagan; this novel contains a simulated school inside a simulated world
Illusions (1977) by Richard Bach
Irreversible (2008) by Liz Maverick : a young woman relives the most perfect week of her life over and over without being conscious of it, the subject of a corporate experiment to create and maintain a time loop. The week is totally manufactured, with actors hired to play friends and colleagues, medication designed to keep her tranquil, and an entire set of "stage hands" working to keep up the authenticity of the sets as they change for various occasions.
Loop (1998) by Koji Suzuki
The Man in the High Castle (1962) by Philip K. Dick
A Maze of Death (1970) by Philip K. Dick
Moongazer (2007) by Marianne Mancusi : a post-apocalyptic underground society decides to pacify its citizens by plugging them into a simulated version of New York City before the war, meanwhile telling the people that they are actually traveling to an alternate reality where they can escape their constricted lives.
Neuromancer (1984) and Mona Lisa Overdrive (1988) by William Gibson
Otherland (1998) by Tad Williams
Permutation City (1994) by Greg Egan
The Metamorphosis of Prime Intellect (1994) by Roger Williams
The Reality Bug, a novel by D. J. MacHale, is set on a world destroyed by simulated reality.
Realtime Interrupt, a novel by James P. Hogan, is set in near future, a cyber reality with its creator trapped inside.
The Remnants series by K. A. Applegate is set on a ship which creates virtual landscapes.
Riverworld (1979) by Philip José Farmer
The Seventh Sally and The Princess Ineffabelle(from the cyberiad) by Stanislaw Lem
Simulacron 3 (1964) by Daniel F. Galouye
Snow Crash (1992) by Neal Stephenson
Sophie's World (1991) by Jostein Gaarder
The Three Stigmata of Palmer Eldritch (1965) by Philip K. Dick
The Trouble with Bubbles (1953) by Philip K. Dick
Time Out of Joint (1959) by Philip K. Dick
Ubik (1969) by Philip K. Dick
Valis (1981) by Philip K. Dick
The Veldt (1951), short story from The Illustrated Man by Ray Bradbury
Vurt (1993) by Jeff Noon
The Wonderland Gambit (1995) by Jack L. Chalker
Words Made Flesh (1987) by Ramsey Dukes
"They", a 1941 short-story by Robert Heinlein, focuses on a man who believes the universe was created to deceive him.

Film, plays & TV series