Understanding and explaining the complexity of the world around us by the set of ‘rules’ lies in a very foundation of science. But satisfactory unifying theory (fundamental theory of physics) is still, if existing, out of our reach. Or are we on a path to it?
Two weeks ago, The Wolfram Physics Project was launched aiming to make this tempting idea a reality. As explained by Stephen Wolfram in his announcement, finally we may have such path, and its beautiful. Working his whole life on a discrete model in computation and physics, Wolfram found that even when the underlying rules for a system are extremely simple, the behavior of the system as a whole can be essentially arbitrarily rich and complex. He argues that fundamental theory would have rules which operate at some lower level, and all of physics would just have to emerge.
The idea of computational reality was presented in 2002 by Wolfram in his book ’A new kind of science’, saying that nature runs its course the same way that computation is run – rules for any system are programs and behavior of the system is computation itself.
Think of some simple rule, for example, each man ever born will have two children and one friend that he will be in contact (this is just made up relation simulating some more explicit relation rule). Start with two connected friends and apply the rule to them. Then let this rule be repeated over and over again, for as long as there is a world - to each child same rule applies. If you are a part of some cycle in this repetition experiment, what you see is reach and complex network of many people. But all that complexness is the result of a simple primal rule repeated in the discrete steps over a long period of time. This can also be represented by graphs –math structures used to model the abstract relations between abstract elements. In fact, many of the complex constructs resulting from nearly a thousand rules are already a part of the Registry of Notable Universes. The visualizations can also be found on the project page . The idea is of course not as simple as this, and is dealing with abstract objects underneath space and time and basically everything we know. In addition, the models involve rewriting rules for collections or relations, rather than updates of values in pre-existing arrays of cells. The fact that the theory is setting a framework for natural sciences (one alternative to mathematics) is also a shortcoming, since proving it wrong is not that straightforward.
After the publication of his book in 2002, Wolfram met criticism from the scientists around the world, arguing that the predictive power of traditional equations is what makes them the best representation of reality there is, classifying his theory as a post-hoc speculation. In his review in Applied Mechanics Reviews(vol. 56, no. 2, pp. B18–B19, March 2003) Mohamed Gad-el-Hak sad: “The pattern-generating capabilities of discrete cellular automata are to supplant the difficult-to-solve or even yet-to-be-found continuum equations of traditional science. But just because the patterns of cellular automata can resemble those of the natural world does not mean that nature must work that way. "
To be honest to these remarks, as explained in the Project manifest, many complex phenomena may stay out of reach of this theory:
“It is intended to be an underlying theory of the whole universe, in perfect detail. If one could run the model long enough, then it is intended to reproduce everything about the universe, including the writing of this answer. However, the amount of computation required to do this would be immense—and the phenomenon of computational irreducibility implies that there cannot in general be shortcuts.”
Now, 18 years after the book, Wolfram is setting up a project to build upon his model. The whole project, code, resources, including papers showing how some parts of present physical theories, including quantum mechanics, can evolve from his model, are published in open-access as a call to the scientific community and anyone wanting to be a part of this effort to see if out in this computational universe of simple rules we can find our physical universe. The tools for the Wolfram Physics Project are built with the Wolfram Language, free to use in Wolfram cloud.
And the project builds upon the basic idea by tackling some of the accepted physical theories. The work of Jonathan Gorard shows some Quantum Mechanical Properties of this Wolfram Model, this new discrete spacetime formalism based on hypergraph transformation dynamics. He shows how wave-particle duality is just one of many immediate consequences of the principle of multiway relativity, how entangled states can be defined, and also how the model satisfies a multiway form of the uncertainty principle . For example, it shows how observer interaction leads to collapsing the evolution of the universal wave function, a phenomenon seen in the double-slit experiment. Here, the observer is any persistent structure within a multiway system that perceives a single, definitive evolution history. From such observer vantage point, the remainder of the universe would also be causal invariant, and any attempt of showing that, in fact, it is not would fail. It is yet to be seen what the opinion of physicists around the world would be on this subject. The fact that Project is self-publishing its findings in real-time can be seen as an advantage, and truly open-access policy. However, it is already raising doubts in Academia (trained by years of peer-review to put its trust in official publishers) that such communication of finding is not validated. The publication method should not, I believe, be an excuse not to critically access this or any other findings. Also, for those of you looking for the explanation of the big picture the upcoming days give a lot to look at and work on, by joining any of the Project parts or rethinking everything you taught you knew. Because ultimately, even if our point of view collapses the rest of the world to our perception, both physically and mentally, that doesn’t mean that we should stop trying to work our way to the fundamental understanding of What Is.