Stephen Wolfram Battles the Theory of Everything
~ a surprisingly coherent path toward understanding the Universe ~
I can feel your reservations regarding Wolfram’s recent claim of a new way to find a fundamental, all-encompassing theory of physics. We hear that a lot. And, Wolfram’s track-record for verbose grandeur, mentioning the foundational work of others only as an aside, has been a valid lingering criticism. Yet, he has been doing a different kind of scientific experiment, using computer simulations of numerous sorts of universes, and the appearance of new kinds of looking are precisely when people discover revolutionary new things. Is that what Wolfram found? Not precisely, but we can cover the gist of his team’s work, and see what might grow from his unique approach.
Universal Rules
Physicists keep looking for the most fundamental laws. Some small set of rules that combine to generate space, time, energy, mass, gravity, magnetism, etc. No scientist expects that, upon finding those rules, we would then be able to ‘simulate everything’ or ‘predict the future’ or ‘know all truths’. Nope. They’re just looking for the most basic instructions that create a cosmos like ours. Like knowing the general way in which electrons are zipping where in a computer, instead of knowing what the software is about to do. That’s all.
Yet, having those rules would give us a reverberating certainty: we can use simulations of these rules, at small scale, to probe reality in ways that no massive, trillion-dollar equipment could. This would generate a panoply of insights, which have a habit of becoming valuable new industries a few decades later. Worth more than a winning lottery ticket, if you wear your generations-long bifocals. So, a lot of people keep looking.
For the most part, physicists have been doing that search from our size down and our size up. We figure out what we can see, and as soon as we can see smaller stuff or bigger stuff, we find equations for that new stuff.
Stephen Wolfram is taking a different approach: he created a simple-universe-rule language, allowing the creation of billions of BILLIONS of different ‘theories of everything’, as well as measurement of the properties that emerge in each of those possible universes. His reasoning for this is simple: Each starting rule generates a universe with properties which are distinct; this distinction is sufficiently large that we can find a universe-rule which needs to match our world in just a FEW places; and with ONLY those matches, we are likely to have found our own real cosmic generator.
I should emphasize that Wolfram is not simply cobbling-together all the disparate behaviors he wants; each universe-rule is one single rule that acts upon a network of dots and edges. Iterating that single transformation creates a lattice of ‘space’ that can be sliced according to causality to form ‘time.’ Due to the fact that he can check these potential-universe-rules quickly, Wolfram is able to weed-out billions of rules at a time, focusing analysis on the most promising candidate universe-rules. Computers are running a simulation which discards hypotheses; that’s science, sans cyclotron.
So, Did He Find Our Universe?
No. But look at this one:
Turns out, Einstein’s Relativity occurs in a wide swath of universe-rules. And many rules are sufficiently complex to generate ‘particles’ with conserved properties, especially momentum and rest mass, the exchange of energy, and light’s speed limit. Even quantum vacuum fluctuations’ production of virtual particles is a common occurrence. Additionally, his rule-generating language produces universes with Feynman-esque branches of particle interactions which merge later into an ‘observed state.’ Everett’s many-worlds interpretation AND wave-function collapse seem to be the trunk and tail of that elephant. So, those facts about our world don’t actually narrow things down much, which itself is a surprising insight!
Yet, our universe has many particularities — the interactions between particles of each universe-rule are radically distinct from each other. If we find a universe that makes quarks and electrons behave as they do here, then we’re probably done.
What Does this All Imply?
There are a few strange conclusions, consistent for the vast majority of interesting universe-rules: the cosmos may still be hyper-expanding, either at the ‘edges’ or ‘within’, forever. And, it creates more matter and energy along the way. Not a ‘conservation of energy’ with a ‘fluctuation of energy that averages-out to zero’ like we’ve been taught. It just keeps making more and more, as a natural unfolding of the rule that forms the space.
So, the explosion of stuff may be ongoing, far beyond where we can ever see. There are possible universe-rules which allow the generation of ‘negative mass/energy’ states, too. Just to get you excited. Wormholes aren’t out-of-the-question, either, because the universe-rules can create graphs with connections between otherwise disparate regions — a leap past all the space in-between.
Another peculiar assertion of Wolfram’s: in many universe-rules, intricate correlations may exist between parts of the space-time graph, yet those relationships can only be observed with explicit and exact simulation of the entire process, at the smallest scale. No shortcuts or simplifications are granular enough to catch these ripples. (Fundamentally, these universe-rules are acting cryptographically upon their minuscule states.) So, any attempt to extract these features by measuring statistical quantities will fail. The universe will remain probabilistic to us, because there are coincidences at the sub-atomic level that we will never be able to prove, though we may notice their gentle ‘noise’ impacting our instruments.
Most compelling was his explanation for how, just as the speed of light limits motion of information in space and time, there is an analogous limit to the cause and spread of quantum entanglement, as well as the pace of decoherence and measurement.
What’s Missing?
In particular, I did not see an explicit explanation for the feedback mechanism from mass-in-motion as a pattern of node activity, because it must cause a tilt in the ‘foliation of the time-like layers of the hypergraph.’ Yeah, and I mean every word of it. Whatever causes that feedback must also be a rule of the system; a rule where the pattern of node activity directs the foliation rule perceived by that pattern… Which implies a super-system for Wolfram’s language of universe-rules, where those feedback mechanisms may differ. Later, he supposes that different observers operate upon their personal foliations, without mentioning a feedback between the observed quantities and irregularities of the hypergraph which would allow a graph structure to change its own foliations. Same problem, there.
Additionally, some of his quantities extracted from these evolving graphs seem a bit forced, in order to find a correspondence with reality, without an explanation for why a particular extracted value should be experienced as one of the properties of a real object. The example that sticks with me: Wolfram envisions that the branches on the ‘multiway graph’ should each be endowed with an energy based upon their ‘angle’, and that this angle, accumulated over the course of a path, should be multiplied by the length of that path, to determine the probability of that arrangement occurring in a quantum measurement (the transition amplitudes). Where did this hat-rabbit ‘angle’ come from? How does this multiplication create a disparity in likelihood? That sounds like another missing rule in a super-system. He combines that measurement with the divergence at each point along those paths, to form quantum path-integrals — which does seem proper, if we assume the earlier axiom of “angles-being-energy,” though it is merely one possible universe-rule.
I have other quibbles — the assumption that ‘light speed’ corresponds to the space-time increments themselves, rather than perhaps only being the ‘greatest tilt observed in normal foliations’ within only the standard ‘vacuum state’ graph connectivity. Under unique local graph connection patterns, other ‘particles’ and ‘velocities’ may be possible.
Yet, none of these invalidates Wolfram’s work — the sheer diversity of universe-rules guarantees that many of them have the capability to describe any given cosmos, so ours is included, if it does follow rules at all. The quest is for the simplest rules that do so. And, in that respect, I still see Stephen Wolfram on the right track, and I expect that time will tilt more physicists toward this particular form of simulation-based experimentation. Much can be learned this way, like looking through a new sort of microscope.
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