The universe that we live in right now might ‘only’ be a computer simulation. In theory, given sufficiently advanced technology, the universe, or a reasonable approximation of it can be the subject of a simulation being carried out by a society whose technology rivals what is depicted in Science Fiction stories. In fact, assuming that type II civilizations (societies that have energy outputs on the same magnitude of that of entire stars) exist, and that they are interested in simulating a universe with comparatively primitive, intelligent life, the probability that we do indeed live in a simulation of the universe is infinitesimally far from 100%. However, since these assumptions are, by their very nature, impossible to prove, it is equally impossible to prove that our universe is indeed being simulated. Nonetheless, in the case of humanity, it is quite likely that if the human race advances to a point where it reaches a level of technical advancement where the computing power required to conduct this type of simulation can be made available to researchers, those researchers would not hesitate to conduct simulations of the universe.
A field of research that would be interested in using this type of simulation is physics. The most intuitively available experiments could be research on origins theories. Physicists would set the simulators to attempt to simulate the behaviour of the universe during the Big Bang, or other theories regarding the beginning of the universe. These simulations could help eliminate theories that would not create a universe with similar behaviour to our own and perhaps prove that one theory accurately describes how the universe began. The simulations could also be used to test different unified theories of physics. For example, if a universe was created, and given the rules of physics as described by string theory (as one example), one could see if the theory could adequately describe all types of actual physical phenomena observed until that moment. Like the origins simulations, it would be able to possibly prove or discredit some of the unified theories of physics. The wealth of possible experiments that could be done with these computational simulations is enormous, giving physicists plenty of excuses to play with this possibility. Yet, these simulations would probably not include the development of life on planets, as intelligent life—especially in civilizations at least as technically advanced as today’s human society—could have effects on planetary bodies that the rules of physics might not be able to predict.
These simulations could also be used to study the evolution of life. One of bigger questions in biology is how sentience arose from species that were not self-aware. Humanity today is unquestioningly sentient, but were the Homo Erectus, or the Neanderthals? What is known is that about 40-50 thousand years ago, the sophistication of human tools started to rapidly increase, along with the development of clothing, art and burial traditions. What is not known is why or how this “Great Leap Forward” occurred. The simulations would probably be able to simulate the conditions of the development of intelligence in order to create a more comprehensive knowledge of how intelligence might evolve in species, including whether or not any extraterrestrial planets might have intelligent life on it. The answers to a number of questions about the development of life from mere minerals and the development of human-level intelligence in species might be more accessible using these simulations.
The third prominent choice for the simulation of a universe is anthropology. Universe simulations could be used to study how people in comparatively primitive societies might behave. A computer simulation would allow observation of human behaviour and perhaps thought without any danger for interference. This is something that should appeal strongly to anthropologists, for whom study requires minimal observer affect, in order to preserve culture. These simulations could theoretically take sufficient parameters to model civilizations of the past for accurate study, rather than creating one with similar circumstances. This could allow for a depth of study—resulting in a depth of knowledge—that most anthropologists can only wistfully dream of today. Anthropological researchers would use the simulations to achieve an unprecedented possibility of analysis of human civilization and behaviour in almost any situation. The level of these simulations, like those of possible biological experiments, would involve simulating a universe with intelligent life; creating a similar situation to the one that today’s society might be in today. That society, once it develops a similar technological base to the one that has evolved on earth today, might also discover that since there is a possibility that, at some point in their technological development, they could simulate a universe, there is a high probability that their universe is indeed simulated.
The three fields of research outlined above are not the only disciplines of study that could utilize the ability to simulate an approximation of the universe, yet they are perhaps the most universally applicable fields that would be involved in such experiments. It is likely that technologically advanced species, as with our own, would value each of these fields: physics to explain the workings of the universe, biology to explain the evolution of life, and an equivalent to anthropology to account for the development of their civilization. Therefore, not only would our species, if it reaches a level of technological prowess that allows it to conduct simulations of a universe of sufficient scale to allow for the development of intelligent life inside, leap at the opportunity, it is probable that if another species that values the scientific knowledge of the origins of its society, or the development of intelligent life, it would do so also.