Recently, there has been widespread confusion about digital physics relating it to the simulation argument.
Digital physics, the hypothesis that the universe is a kind of digital computer is most likely true. Simulation argument is not. It is a very naïve metaphysical argument based on ancient fallacies of solipsism and creationism.
Some physicists, apparently, seem to think that if they can prove digital physics, this would mean that we are living in a simulation. I believe that the philosophical illiteracy of those physicists may be betraying them. Not quite understanding what the digital physics hypothesis is, they have succumbed to a trivial error. And although they have the technical means to investigate the granularity of the universe, they do not have the means to understand a simple conceptual hypothesis.
It is somewhat alarming about the cultural degeneration our society is going through when physicists are talking about “simulators”, i.e., alien programmer deities outside our realm. This interview vividly demonstrates their philosophical ineptitude.
The more interesting thing is that the press immediately made this a popular news item, and now every half informed person in the world is talking about this. Therefore, I thought a theoretically informed explanation from the high floating auto-erotic circle might be in order.
Digital Physics can be true without needing any simulators whatsoever. If it is true, it is probably going to turn out to be a low-level computer architecture that has a Planck-scale structure. It is hypothesized to be a Reversible Universal Cellular Automaton (http://en.wikipedia.org/wiki/Reversible_cellular_automaton), although I have considered Graph Automata as more fitting as it could correspond to a space-time lattice. Cosmology in digital physics can be likened to an evolutionary programming system, in which programs evolve due to mutations. The mutations can be deterministic or non-deterministic. However, in the end, the universe is merely an evolving program on a digital computer, if digital physics is true. Particles, stars, galaxies, they would have all evolved as surviving programs in an immense computer system.
This evolutionary interpretation is obviously much more scientific than positing some “simulators”. I shall not further investigate why Bostrom’s simulation argument is wrong-headed, which I’ll save for another essay, perhaps. For now, suffice it to state that I do not consider it scientific because it is based on many metaphysical assumptions, like any other variant of intelligent design, i.e., creationism.
However, the concern of Dr. Silas Beane about simulators “faking” real physics using discretization is naïve at best to say. It depends on this childish notion that “real physics must be continuous”. He believes that if we were not living in a simulation, our physics would be continuous, and there would be no granularity to the universe. This is a muddled view of physics, to say the least. It not only fails to take into account the founding idea of digital physics, as envisioned by the great Konrad Zuse and one of our favorite MIT scientists Ed Frenkin, but it also fails to adhere to the vision of Hooft (see the wikipedia article on his holographic principle and Wheeler (see this book excerpt about his “It from bit” slogan). When we talk about the holographic principle, we do not mean to say that the hologram, or The Great Universe Computer rests in a computer laboratory in some Really Continuous Exotic Universe. On the contrary, Digital Physics claims that such an exotic continuous universe does not exist at all! There is no lab, the digital physicists proclaim: the universe is the computer.
That is to say, the memory cells of the computer correspond to physical states. Its operations / transition rules, the description of its computer architecture correspond to physical laws. And the programs in its memory are physical objects / processes / events. There is no simulation. Programs are things. Computations are events. We are programs. And that is all that there is to the universe.
This cold, hard, scientific world-view is unfortunately very difficult to appreciate for the philosophy community usually compromised by dualists and vitalists. It surely requires letting go of much fantasy that contaminates our common sense; it is not as exciting as a world in which you can expect to find an infinite expanse of space on your fingertip, or where you can carve up a sphere and obtain two identical spheres of the same size. Indeed, the fantasies about Continuum and all sorts of Exotic Universe imaginations depend on our misdirected mathematical ventures. For at least one minor difficulty with continuum: the mathematical continuum permits discontinuous functions. Physically, if discontinuous functions existed, they would be fun to watch. Some physical process, like fire, would start, and then it would transform into something else, say, like a bird, instantaneously, just like magic. That is of course merely an example. However, interestingly, if simulators existed, they would be able to use a Continuum without any discontinuous functions, which is possible with the set of Computable Reals, or set R_c (see the wikipedia article on computable numbers). That would be a perfect continuum with no imperfections detectable by the simulated. (Extra credits to readers who can spot the related computable mathematics theorem.) That is to say, Dr. Beane is making this ridiculous commentary on his otherwise valuable, perhaps revolutionary work, only because he fails to apprehend the philosophical and mathematical underpinning of digital physics. However, I am confident that he can be debugged.