The Simulated Universe
The Simulated Universe argument suggests that the universe we inhabit is an elaborate emulation of the real universe. Everything, including people, animals, plants, and bacteria are part of the simulation. This also extends further than Earth. The argument suggests that all the planets, asteroids, comets, stars, galaxies, black holes, and nebula are also part of the simulation. In fact the entire Universe is a simulation running inside an extremely advanced computer system designed by a super intelligent species that live in a parent universe.
In this article, I provide an exposition of the Simulated Universe argument and explain why some philosophers believe that there is a high possibility that we exist in a simulation http://mashreq.edu.sd/ . I will then discuss the type of evidence that we would need to determine whether we exist in a simulation. Finally, I will describe two objections to the argument before concluding that while interesting, we should reject the Simulated Universe argument.
The possibility that we exist in a simulated universe is derived from the idea that it is possible for a computer to simulate anything that behaves like a computer. A computer can run a simulation of any mechanistic system that follows a pre-defined series of rules. Now, because the Universe is a rule following system that operates according to a finite set of physical laws that we can understand, it follows that it can be simulated by a computer.
The proponents of the Simulated Universe argument suggest that if it ispossible for us to simulate a universe, then it is likely that we actually exist inside a simulated universe. Why do they have this belief? Well, proponents of the Simulated Universe argument suppose that if it ispossible for us to build such a simulation, then we will probably do so at some time in the future, assuming that our human desires and sensibilities remain much the same as they are now (Bostrom 2001:pg 9). They then reason that any species that evolves within the simulation will probably build their own Simulated Universe. We know that it is possible for them to do so, because they exist, and they are inside a simulated universe. It is possible to continue this nesting of universes indefinitely, each universe spawning intelligent species that build their own simulations. Now, given the near infinite number of child universes, it is more likely that we exist in one of the billions of simulations rather than the one parent universe. This becomes especially apparent when we consider the possibility that within these universes there may be many worlds with intelligent life, all creating their own simulations.
So how does this all work? Well, when you look at a computer running a simulated universe it is not the case that you can switch on a video screen or computer monitor to peak inside the universe. The computer does not contain virtual reality creations of people living out their lives in their world. It is not like playing a videogame such as "The Sims" or "Second Life". There are no graphics involved. From the outside looking in, all you see are numbers. That's all it is. Complicated manipulation of numbers. As with all software, these numbers are instantiated through the computer hardware. They are stored on permanent storage devices such as Hard-drives, and they are moved into RAM to be operated upon by the Central Processing Units (CPUs). The numbers in a simulated universe programrepresent the laws of physics in the universe. They also represent matter and energy in the universe. As the program runs, the numbers are manipulated by the program rules--the algorithms representing the laws of physics. This manipulation yields different numbers which continue to be operated on by the program rules. Large data structures of numbers are moved around within the computer's memory as they interact with other data structures. As the simulated universe grows, these structures become increasingly complex but the laws that govern their behavior remains constant and unchanged.
So, from the designer's point of view the simulated universe contains nothing other than complicated data structures. But for the creatures that exist inside the simulated universe it is all real. They look out of their windows and marvel at beautiful sunsets. They walk around outside and enjoy the smell of freshly cut grass. They may study the stars in their sky and dream about one day visiting other worlds. For the inhabitants of the simulated universe everything is solid and tangible. But just like the real universe, it is all reducible to numbers and rules.
It is important to note that the computer is not simulating every subatomic particle in the universe. In his 2001 article, Nick Bostrom points out that it would be infeasible to run a simulation down to that level of detail. He suggests that the simulation need only simulate local phenomena to a high level of detail. Distant objects such as galaxies can have compressed representations because we do not see them in enough detail to distinguish individual atoms (Bostrom 2001:pg 4).
This is a point that we can take further. Perhaps the entire universe, including local phenomena, is compressed in some way. The simulation could be "interpreted" by its inhabitants as being made from individual atoms and subatomic particles, while in reality it is completely different. If we look at modern physics, we see that this is a reasonable possibility. Consider the indeterminacy principle in quantum physics. An observer cannot measure the position and momentum of a particle simultaneously. Furthermore, it seems that subatomic particles have no definite position or momentum until an observation is made. This is because subatomic particles do not exist in the sense we are used to experiencing on the macro level. Given the fact that we do not directly see subatomic particles we can conclude that their existence is an interpretation of a reality of which we have no direct access. In a simulated universe, this reality could take the form of data arrays which represent matter and energy.
The Original Simulated Universe
The Simulated Universe argument is not new. Frank Tipler put forward the idea of a Simulated Universe in his 1994 book The Physics of Immortality. He suggests that we may all become immortal when we are recreated inside a simulation of the universe at some time in the distant future. Tipler argues that at some point in the future, humans (or some other advanced species) will develop the technological ability to simulate the universe. Humans that reach such a point in evolution will, according to Tipler, have an extremely advanced sense of morality. They will recognize a moral problem with the notion of intelligent conscious beings living their lives and then dying. So to correct this moral problem they will recreate everyone that came before and let them live an immortal life inside a simulated reality.
There are problems with this view. The first, and most obvious, problem relates to the moral dilemma that these super advanced humans finds themselves in. Why do we assume that there is a moral problem with people dying and no longer existing. Sure, from our perspective it seems wrong, but from the perspective of humans with a super-evolved moral sense it may be more problematic to recreate us.
The second problem with Tipler's idea is one of implementation. In order to recreate humans that once existed, future humans would require knowledge of each human being's unique properties. This includes their personality, their memories, and the structure of their brains. It is unlikely that future humans will be able to gather this sort of information. The best they could do would be to create a new universe from scratch, switch it on and hope for the best. Their simulation will unfold according to the preset collection of rules that they built into it. After time, their universe will evolve and planets may form within it. Life could evolve on those planets and one day become intelligent enough to build its own computer simulations of the universe.