Quantum Computers and Artificial Reality

Quantum Computers and Artificial Reality

Deutsch, Vaidman and Palga's experiments to falsify the collapse and Bohm approaches to quantum mechanics all rely on the fact that we will be able to develop artificial consciousness. This is based on a functional theory of the mind and the idea that we will develop large scale quantum computers. All computers can be described as Turing machines, a concept devised by English mathematician Alan Turing in 1936 (Turing, pp.433-460). Moore's Law, devised by Intel co-founder Gordon Moore in 1965, states that the number of transistors on a microprocessor doubles every eighteen months. If this process continues, then by 2030, the circuits on a microprocessor will be measured on an atomic scale. American physicist Paul Benioff first considered a quantum Turing machine in 1981 (Benioff, pp.495) and in 1985, Deutsch showed how this could be done (Deutsch, pp.97-117).

A quantum computer is faster than a classical computer because a classical computer stores information in definite states, in terms of 1s or 0s. A quantum computer can store information in a superpositional state and hence perform more than one calculation at once. Deutsch argued that these calculations are most naturally understood as being computed in parallel worlds and that this "places an intolerable strain on all interpretations of quantum theory other than Everett's" (Deutsch, pp.97-117). Other interpretations lead to the question of where the correct answer was computed.

In 1999, physicists at IBM developed a 3 qubit quantum computer, this was followed with a 5 qubit quantum computer the following year and by 2001, they had developed a 7 qubit computer which could be used to calculate prime factors (Vandersypen et al., pp.883-887). In 2007, Canadian company D-Wave claimed to have developed a 16 qubit quantum computer which could solve sudoku puzzles. Large scale quantum computers would allow any classical encryption to be broken almost instantly, as soon as one is built no information on the internet will be safe. It is thought that quantum computers will be used to design others and there is no known physical law preventing them from reaching the state where they can simulate conscious experiences.

This leads back to the ancient philosophical question of whether we could be living inside of a simulation. If we are then we would not necessarily have a body on the outside and other people would not necessarily be conscious, although it could be argued that it would not be possible for something to have a brain state that appears conscious if it is not. Dreams are a type of simulation and so we know that this concept is possible. Outside of the simulation time may run in a different frame and we may not notice if the simulation was switched off for an extensive period. The simulation may be stored on different computers in different places and we can have no idea of how safe they are. Even if we were to exit one simulation, we would have no way of knowing if that world was a simulation too and so no way of ever knowing that any world is real.

In 2003, Swedish philosopher Nick Bostrom argued that if it is possible to simulate entire universes, then most advanced civilisations will probably come to build these simulation machines (Bostrom, pp.243-255). Brostrom predicted that one day everyone alive will exist inside of a simulation, making it almost certain that we are in one now. Human consciousness is predicted to require about 10^16 - 10^17 (ten hundred million, billion to one hundred million, billion) operations per second and Bostrom predicted that it would take about 10^33 - 10^36 (one million, billion, billion, billion to one thousand million, billion, billion, billion) operations per second in order to simulate our current experience of the universe. In 1992, American engineer Kim Eric Drexler showed that a system the size of a sugar cube could perform 10^21 operations per second and in 2001, American computer scientist Robert Bradbury showed that a computer with a mass similar to that of a large planet could perform 10^42 operations per second.

In 1986, American physicist Frank Tipler argued that if the universe ends in a big crunch, then anything inside the final singularity will continue to exist forever, from their perspective. Tipler referred to this as the Omega Point. Inhabitants of the singularity would have enough energy to create an infinite amount of simulated worlds and may wish to live in one. Deutsch defended Tipler's Omega Point theory in his 1997 book The Fabric of Reality. After the discovery of dark energy in 1998, Tipler extended his theory, arguing that the big crunch will still happen after the universe becomes a void, when all of the matter has decayed. However this may not be necessary, assuming that Everett is correct, any worlds that do undergo a big crunch would be able to simulate those that do not. Tipler's theory is also reliant on the idea that all theories of quantum gravity which disallow singularities are false, including string theory.

One problem with Bostrom and Tipler's arguments is that they rely on the fact that we know what advanced civilisations are likely to do. If we could ask any of our ancestors what the 21st century is like, it is doubtful that many of their predictions would be correct. The further back we could go, the more likely it is that they would be wrong. Bostrom and Tipler's ideas also suggest that the laws of physics would be the similar on both sides of the simulation. This may be the case, but it is also possible that if we are in a simulation then our knowledge of any external laws is severely limited. If, for example, the characters inside of a simple platform game could become conscious then they would have to obey the same laws of physics as their human creators, but they would not necessarily be able to derive them. There would be many more laws which they would discover first, those programmed into the game, and any experiments would be limited by these programs.

References

Benioff, P., 1982, 'Quantum mechanical Hamiltonian models of discrete processes', Journal of Mathematical Physics, Vol.22

Bostrom, N., 2003, 'Are you living in a Computer Simulation?', Philosophical Quarterly, Vol.53

Deutsch, D., 1985, 'Quantum Theory, the Church-Turing Hypothesis, and Universal Quantum Computers', Proceedings of Royal Society of London, Vol.400

Turing, A., 1950, 'Computing machinery and intelligence', Mind, Vol.59

Vandersypen, .L.M.K. et al., 2001, 'Experimental realization of Shor's quantum factoring algorithm using nuclear magnetic resonance', Nature, Vol.414