The Universe Is a Giant Abstract Turing Machine That Doesn’t Need to Be Run
If U() is the set of all possible Turing machine definitions, U(a) is just one of them, one that represents ours. This philosophy is also termed digital physics, and this essay attempts to put the philosophy in layman’s term.
Our universe is probably defined by a set of 10 or so functions or physics rules plus 10 or so initial variables (representing half of our universal constants, with the other half being implied by the first), that when played out over a power tower set of loops, would describe the position and velocity of every particle in the universe. Our universe is much like Conway’s Game of Life, where simple rules lead to complex phenomena. We know our universe has a compact definition, based on our progress towards a Unifying Field Theory. And we can rewind nearly everything in the universe back to the Big Bang.
It seems that life as we know it is rare, but U() is infinite. It represents every possible computer, even a non-compact one where every frame of our existence is simply hard-coded. Even though there are a power tower number of particles, velocities, and moments in our universe, there exists some U(k) that could just have all that information by assertion. However, we are likely not just an abstract film reel, as the odds that the next moment after reading this text would follow the rules of physics instead of being pre-written, particle-by-particle, is astronomical.
This assumes the universe is computable, which is a similar claim to Einstein’s “God does not play dice” comment. We don’t want to believe the universe is computable because to do so would imply it’s deterministic, and therefore that we have no free will. But our need to have free will does not make a good argument.
This also assumes that matter doesn’t exist, which comes from the idea that matter actually can’t exist. There can’t be a thing outside of nothing because something would have had to bring that thing into existence, and that something would have had to have another something before it, and so on until the first thing. As the saying goes, “At some point, something must have come from nothing.” But there could also just be nothing. And this argument goes beyond the notion of causality. To say that every thing had to be brought into existence by some other thing does not require a universe with cause-and-effect, but rather than in order for anything to be a material, it requires a material-maker, -definer, or -creator, even if that creator doesn’t exist as an entity in space-time. But because we can’t have a first creator, nothing can be made, and therefore there can be no matter. The Big Bang or the first bing bang had to be asserted by the system. Or to generalize, the first action of the universe had to just be.
The physicist Wheeler came at this problem through his essay “It from Bit”, which is an attempt to argue the computability of the universe. He brought to bear the sum total of his understanding of modern physics to say that all physics is observation or measuring, and to measure requires the interaction of discrete bits of information. If our universe is physics, then, our universe is ultimately information.
Consciousness seems to get in the way because, “I think, therefore I am.” We are nothing if not smacked in the head every second by our own existence. But an alternative statement, as either quoted or made by Daniel Dennet, the seminal consciousness thinker, is, “It thinks, therefore it is.” Or, consider the viewpoint of a non-playable character in a video game, one who has a pre-scripted series of paths to run through, but ultimately serves as a provider of quests or tools. That character can see the ground, can recognize other objects and can react to other players. It’s a crude and simple notion of consciousness, but one that exists only in software. If you removed all the human players, and just ran the game in the background, with the monitor turned off, at some time = n, that character could pick up an apple or look in a mirror and ponder their existence. Assume there were no random elements, which when making computers, requires some external input to be truly random, such as a temperature reading from a processor or the current system time, determined by whenever the human executed that. Barring a random, external injection, then at the same time = n, this character would have the same exact moment of pondering.
To start with the briefest number of assumptions would exclude all human biases, such as existence, consciousness, and free will, all of which, for the purposes of describing the universe, are immaterial.