“Which ‘theory of physics’ (framework) do you believe in?”
What I believe in most, in physics, is the “Scientific method.” But what is the scientific method? A complete answer would talk about how we learn from experience, from different streams of experience or observation. But for here and now, I make just one point:
A true scientist (a rational or sane person) would simply not feel compelled to make a Commitment of Faith or Belief to any particular theory, in the absence of overwhelming empirical evidence. In fact, a rational or sane person would resist the pressure to make such a commitment, in the absence of really strong evidence to justify it.
In my IJTP paper, I explain why we DO have overwhelming empirical evidence to rule out the
usual Copenhagen version of quantum field theory. At different times, I pay respects to four different posible
theories of physics:
1. The universe as a “Great Mind,” ultimately obeying mathematical laws much closer to what we study in the neural network field than to anything now used in physics.
2. “MW+BPT” – the “many-worlds” theory of physics, as cited in the IJTP paper, with backwards time physics attached. (BPT is essentially a way to represent the boundary conditions at t=±∞.)
3. “CFT+BPT”: classical field theory (Lagrange-Euler field theory, or the extensión of it to mixed forwards-backwards stochastic partial differential equations)
4. Miscellaneous categories of “unknown theories,” like “its form bits” and the kinds of alternative theories which Wolfram and Chua have sometimes discussed.
My IJTP paper basically tells us that MW+BPT really is the most appropriate theory for hardcore practical
Physics today. Given an acceptable Hamiltonian operator, it fully specifies what to predict. It provides mathematically well-defined theories for a much wider range of operators H than what is allowed in conventional
Renormalization theory. And nothing beats it in fitting empirical data from the lab today, at least if we don’t talk about gravity.
But when I form my personal subjective probability estimates today, I don’t really believe that MW+BPT will ultimately turno out to be true. Maybe I’d give it a 2% probability, just to be open-minded, but it’s just so ugly that it’s hard to believe. I treats time as something totally different from space, despite the string hint from special relativity that this isn’t the case. It can’t make up its mind whether space is 3-N or infinite dimensional. It has energy jumping from
hyperplane to hyperplane in Fock space as if the true cosmos were full of weird antennas or pure essence sticking out.
And it is suspiciously similar to the kinds of things which EMERGE in the statistical description of classical fields and particles.
And so, my gut feeling is – 40% probability for some kind of Great Mind theory, 40% for CFT+BPT,
20% for miscellany like number 4. (40+40+20+2+…>100… but none of these subjective probability estimates
is that precise.)
Though I find the Great Mind concept very attractive, as does David Deutsch and many others, I am frustrated by the challenge of trying to translate that concept into an operational framework for doing physics that we can begin to test.
I have tried at times, but never quite gotten there. I was very intrigued by Wolfram’s comment that he can get general relativity as the emergent outcome of a more fundamental probabilistic graph model. But when I tried to track that down,
It didn’t get so far. In sum – Great Mind is a very legitimate area of inquiry, but I don’t see it engaging with physics quite yet. It deserves some kind of active attention now, aimed at making it more viable somehow, but I put my energy more
into MW+BPT and CFT+BPT.
CFT+BPT takes real courage, like believing planets revolve aroound the sun in a culture which has long enshrined the earth as the center of the universe. True science would actively encourage the development of such a clean new
framework, especially now that my IJTP paper disposes of the traditional serious objections. In fact, a true scientist,
like a good market invetsor, would feel a very special duty to fill in this huge hole in today’s physics, exactly
because it is a huge hole. But it is not easy. In an empirical world of bosons and fermions which displays very complex entanglement and coherence effects, how could any CFT model possibly fit empirical data?
In fact, I have spent some time looking into that. I have posted a series of papers at arxiv.org which, in my view, point the way to answering that question – and even to coming to grips with empirical data in nuclear physics which the traditional frameworks have proven unable to come to grips with. There is real empirical content there, and important decisive experiments which need to be performed – if only the pseudo-scientists who object to empirical tests and prefer theological correctness did not get in the way.
Given the complexity of the intellectual politics here, I am mainly working on “one step at a time”
(one revolution at a time, really), and hoping there will be time to pass on enough of the future steps that others can follow up on them. Perhaps the next step is a better understanding of time, which is posible even within the
more conservative MW+BPT framework.