Recently, I get involved with Wolfram Physics Project. I did some research, and I wen down with it (oh, well, let's say I've just understood what's at the base of it). Since it's quite intresting I thought to write down two rows, as we could say...
Well, Stephen Wolfram is a reference figure in the programming and maths. He started Wolfram Alpha, a website that ties to give an answer to "every" question, using algorithms to scan an enormous database of informations. He's also responsible of Mathematica, an informatic system, used by scientist in all the world.
Well, the Wolfram Physics Project is an ambitious attempt to develop new physics about our universe. The new physics, he says, is computational. The guiding idea is that everything can be reduced to the application of simple rules to the fundamental building blocks.
Currently our understanding of the universe we live in and the physical rules that govern it is pretty good, but it has a limit. In fact, we have two rather well constructed theories, namely the theory of general relativity and quantum mechanics. They both explain their respective areas of application quite well: Relativity explains gravity and works well with large-scale models of the universe, that is, on very large entities; while Quantum Mechanics explains the relationships between particles on a subatomic scale, and therefore very small entities. So far, everything goes on, but we humans are curious, and we have already discovered that there are cases in which the two theories should be applied together, one example above all: black holes. HUGE quantities of mass (and therefore gravitational effects) enclosed in VERY SMALL dimensions, and therefore subject to quantum effects which - in fact - make us somewhat blind in this regard.
By "Theory of everything" we mean the attempt we are making, as human beings, to converge the two theories into one that is - precisely - able to explain ... EVERYTHING.
Currently the best recognized approach is String Theory, but it is proving somewhat unsatisfactory, for some.
Wolfram's idea, if I have not misunderstood, is to provide an alternative to this theory, and he wants to do it through a branch of mathematics called graph theory. It studies groups of points, or nodes, connected by lines, or edges.
You can think a little about a social network, looking at the figure below: you start with a and the "add three friends" rule is established. At the first step a will add three friends, at the second step all these 4 nodes (therefore including a) will add three friends, and so on ...
Continuing in this way, the network will soon form a very complex graph.
Wolfram's idea is that applying a rule many times creates a complex network of points and connections. His proposal is that the universe can be modeled in much the same way. The goal of physics, he suggests, would be to work out the rules that the universal chart obeys.
The key point is that a complex graph can look like geometry. For example, imagine a cube and a graph that looks like it.
In the same way that a collection of points and lines can approximate a solid cube, Wolfram argues that space itself can be a mesh that unites a series of knots. In short, Wolfram argues that extremely complex graphics resemble surfaces and volumes: adding enough nodes and connecting them with enough lines we would form a kind of lattice. The idea would be, therefore, that the space itself can be thought of as a mesh that combines a series of knots in this way.
You may be wondering what this has to do with the reunification of physical theories. Well, quantum mechanics acts on particles, which are discrete by their nature, while relativity treats the universe and gravity as a thing with continuity (and therefore NOT discrete).
I therefore believe that the basis of the project is the desire to try to see if it is possible to arrive at the theory of relativity and / or its geometry, but starting from a discrete structure, such as graphs. If it were possible, it could be a step forward ...
Stephen Wolfram believes that space itself can be a complex network of points connected together by a simple rule that is repeated several times.
On the site there are numerous examples of how one (or more) rules, applied subsequently, can lead to complex structures.
There are criticisms, some concern the lack of a basis of studies consistent with the path that he would like to take, and others mention the similarity with two other existing approaches to quantum gravity: the theory of causal sets and quantum ring gravity.
However, the project is noteworthy. First of all, Wolfram has a large audience and will do much to spread the approach it supports. Proponents of ring quantum gravity particularly complain about the predominance of string theory within the physical community. Wolfram can help support a paradigm shift in physics.
Secondly, Wolfram offers a very careful overview of the project from the basic principles of graph theory to general relativity. This will make it easier for individuals to keep up with the general approach and potentially make their own contribution.
Thirdly, the project is "open source", so it could attract, and is available, for any citizens with scientific bases, even if they are hobbyists.