After Spatial linked that YouTube video of that guy Lang, I've looked into his theory of everything, namely ctmu.
Despite the fact that philosophy stackexchange ridicules the guy, and there are a bunch of undergraduate physics students who are quick to say he's wrong, he's not doing things at random, and I think he genuinely is attempting to solve some profound issues in philosophy. I can't say I understand the entire theory, but I think I get why he says some of the things he says. After skimming through his theory, I've stopped to think about some of the philosophical issues I've brushed off in the past as irrelevant.
Why is this? For most of my life, I've held a deep conviction that science attempts to find the truth about the world. So I hold kind of like the common sense view of science. So for example when I talk about electrons, I assume electrons are "real" entities that exist in the world, or at least approximate something real in case we lack a complete description. The purpose of scientific inquiry, to me, is to discover the ultimate truth about the world. This was what originally drove me to science. However, as of late, I've started to profoundly question that belief, because of what I see as deeply concerning issues with science.
It's worth mentioning what brought up these thoughts. This weekend, I was preparing a book chapter on connecting Bayesian hypothesis testing with table top quantum experiments. I wanted to explain how one can conclude that, say, it is more likely that the electrons have a quantity called spin and exist in a superposition of states, than local hidden variable theories make a prediction regarding the correlation of spins, how to connect that with experimental design, and how to translate the digitized results to a likelihood ratio of the two hypotheses under a bayesian lens.
I wanted to break down the issue to parts, so I tried to explain the issue in simpler terms, by using a story how when I was a kid my friend told me that there are dinosaurs in our family's garage. I believed my friend, until my mom forced me into the garage and showed me that there were no dinosaurs. The problem here can be broken down to different components, namely the evidence for the two hypotheses, Occam's penalty, prior for the two hypotheses, and prior information that was accessible to me and my mom.
The evidence of seeing the empty garage is what convinced me that there were no dinosaurs there, combined with all my past experience that I could trust my sensory experiences, and the assumption that the nature of reality was what my sensory experiences purported it to be. While my mom had lived much longer than I had and was therefore more convinced that no dinosaurs existed, I had no such strong prior information, which is why I believed my friend. One could have also applied Occam's razor here, that it's probabilistically a much simpler hypothesis that my friend was lying than that there was a string of extremely unlikely random coincidences that not only made dinosaurs not extinct but also placed them in our family's garage.
Likewise, I can apply Bayesian hypothesis testing to an experimental design regarding tests for Bell's inequality. I wanted to make the argument rock solid, to show exactly what science can answer probabilistically, so that I could defend how science discovers true things about the world. However, I found out I can't do that, because there are very concerning issues with the presupposition that appear to defeat the entire purpose of the classical view of science.
To understand why that is, let me take one of the presuppositions of Lange's CTMU. He defines reality as things that can in principle be perceived, as per his M=R principle. This sounds random and inane without the right context, because the first question anyone would ask is, what about things that cannot be perceived? Couldn't reality be divided to things that we can perceive, like matter or bacteria, and things we cannot perceive, like the collapse of the quantum wave function? The answer is the seemingly absurd, well, we define reality as those things we can perceive. The reality as described in the brain in a vat scenario cannot be perceived so it's not part of reality. It's a profoundly anti-realist position in my opinion, because realism assumes that the scientific theories we use to describe reality are, well, real, not just that science produces useful predictions for measurements, which are real and can be perceived. So when science says there are things like electrons, we are not just referring to the mathematical framework that correctly predicts the interaction between electrons and our experimental devices, but literally that there such things as electrons, and its not just a matter of electrons being useful fiction that helps us predict experimental results.
So why would anyone define reality in the way Langan does? Isn't it really stupid? Well, no. To understand why it might not be silly, it's illustrative to understand the classical position and why it runs into issues.
My deeply held belief is that we can discover the Truth with the scientific method. Our scientific theories approximate this truth and as we gain more information, we get closer to the Truth using the scientific method. So for example we can test if P is true or false, where P could be a statement that electrons exist, using standard hypothesis testing. This is the common sense scientific view.
The view runs into issues with this assumption that we get closer to the Truth using the scientific method. In particular, uppose that we are a brain in a vat (another version of we live in the matrix), hooked to a computer. The computer feeds back information and sensory experiences that make our experience of reality "as if" we lived in a naturalistic world with the physical rules we experience every day, while the outside world is infinitely more complex. All our attempts at discovering the truth would be really about discovering the rules of the computer, as opposed to discovering the Truth. So the assumption that, just because our approximate theories are highly predictive, doesn't mean that what we're doing is inching closer to the truth. Langan's CTMU gets away from this issue by positing that reality are those things we can perceive. So the universe beyond our sensory experience posited by the brain in a vat hypothesis is by definition not part of reality. Constructivist view gets away by saying that the aim of science is to make successful predictions, not discover truth.
You might think this is a trivial or a purely philosophical issue. However, take quantum wave function collapse as a practical example. We posit that electrons are described by probability waves that are localized when we measure them. So, before the measurement, they are described by wave theory. When we make a measurement, the wave function collapses and we get a measurement in alignment with any theory that describes the electron as a particle. According to the current theory of quantum mechanics, we never observe the wave function actually collapse. We just observe the consequences after the collapse. Hence, does there exist such a thing as a wave function or a state vector? We can only really be sure that our theory is good at making predictions, but is the theory about electron waves just useful fiction?
We can be sure that the meausrement results are correct. However, in this case, there are many entirely different, mutually exclusive descriptions of what is really happening "under the hood" that all predict the same experimental results: Many world theories (quantum decoherence) pilot wave theory (non local realist theory), Copenhagen interpretation (constructivist view), and superdeterminism (global conspiracy). Given that we can only rely on measurements, and given that all these theories produce virtually identical predictions, and are mutually exclusive, how can we assert that science is converging on truth through inspection of evidence? The local realist would assert that given enough time, we will find out which one is the Truth, but would do so without evidence.
Ive thought about some of the solutions posited by scientific realists, but I find them unsatisfactory. They appear to be as faith based as religion. The main contender in mainstream science appears to be scientific constructivism or pragmatism, but those appears to defeat what the purpose of science was in the first place, answering truth claims.
