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There are four profound problems: 1. The first is philosophical. GR is classical, with smooth continuous fields, locality and determinism*. QM has super

There are four profound problems: 1. The first is philosophical. GR is classical, with smooth continuous fields, locality and determinism*. QM has superposition, entanglement, non-locality and indeterminism. GR seems more intuitive, but QM seems more of an irreversible revolution, so slight win. 2. The second is philosophical. GR provides equations for how spacetime is warped by matter and energy (background independent). QM assumes a static background 'stage' of spacetime (wavefunction is a function of spaces, Schrodinger Equation is a wave equation wrt time, so background dependent). GR seems deeper, QM seems superficial. GR wins this hands down, QM has to change or be extended to make it background-independent (perhaps see String Theory). 3. The third is philosophical. QM has a 'measurement problem'. Wave: the Schrodinger Equation is linear, unitary, time reversible and (hence) information preserving. Particle: measurement is discrete, discontinuous, non-linear and information destroying. So there is either a bizarre mismatch between the two parts of the theory, or you strike down measurement, and propose the Many Worlds interpretation, which punts all the measurement problems into other causally disjoint 'worlds', without a clear way to establish probabilities. This is purely a problem with incomplete/incoherent explanation by QM. The fact that physicists cannot agree on an interpretation is damning (is the wavefunction real? is Hilbert space real? what is measurement?) 4. The last is practical. QFT is just Fourier Analysis where it true, and a terrible hack everywhere else: double quantization, renormalization of infinities, energy cut-offs, virtual particles, incomplete Standard Model (neutrinos?), why 3 generations, what is the vacuum (dark energy). My scorecard is 40:60 draw in QM's favor, GR total win, and two QM no-contest own-goal losses. So a clear GR win, in the sense that a new integrated theory of Quantum Gravity will have: - a copy of GR, even if it is emergent from discrete substrate - radically overhauled version of QM (philosophical, explanatory and model details), even as predictions don't change much, and some important philosophical revolutions are preserved My own personal pure guess is that the next level substrate is discrete. The two signposts are: holography, dimensional reduction and AdS/CFT-ishness; and the huge clue that quantum entanglement seems to create relativistic spacetime (but perhaps not proper time).

nico 2y ago
Thank you for the detailed explanation. These are fascinating topics What do you think would make a bigger impact in terms of our understanding of the universe?
mikhailfranco 2y ago
I pondered a little bit more to uncover why I felt this way about GR and QFT. I am sure there are no realized infinities, and I don't think nature can have an if statement. It can have hysteresis curves, with some extreme exponent, but it cannot have a conditional. A square wave is an infinite Fourier Series, but infinite does not exist, so it is truncated, and there are no zero-step jumps. No Dirac Delta Function. Quantum jumps are layered over tunneling and decaying exponentials, but they do not need step changes or conditional laws. So GR is pure in this sense (except singularities, but all bets are off, and I don't think they exist - no infinities, no infinitesimals that actually become zero). Singularities are not a prediction of GR (despite Penrose, whom I admire enormously), they are just a realm without solutions, a Terra Incognita, where we know we need a better theory. One final thought... the Heisenberg Uncertainty Principle (HUP) is just Fourier Analysis. Every physicist and electrical engineer, just says, "yes ok", and moves on, even though there are various mystical properties ascribed in pop-sci woo-woo explanations. The one finding of the Wolfram Physics project that made me sit up and pay attention, is that they derived HUP as composed of two different structures of ambiguity (simplifying enormously: across and ancestrally within the branchial space). That sounds ~right to me, and indicates some profound insight they are generating from discrete combinatorial approaches.

nico 2y ago

Thank you for the detailed explanation. These are fascinating topics What do you think would make a bigger impact in terms of our understanding of the universe?

mikhailfranco 2y ago

I pondered a little bit more to uncover why I felt this way about GR and QFT. I am sure there are no realized infinities, and I don't think nature can have an if statement. It can have hysteresis curves, with some extreme exponent, but it cannot have a conditional. A square wave is an infinite Fourier Series, but infinite does not exist, so it is truncated, and there are no zero-step jumps. No Dirac Delta Function. Quantum jumps are layered over tunneling and decaying exponentials, but they do not need step changes or conditional laws. So GR is pure in this sense (except singularities, but all bets are off, and I don't think they exist - no infinities, no infinitesimals that actually become zero). Singularities are not a prediction of GR (despite Penrose, whom I admire enormously), they are just a realm without solutions, a Terra Incognita, where we know we need a better theory. One final thought... the Heisenberg Uncertainty Principle (HUP) is just Fourier Analysis. Every physicist and electrical engineer, just says, "yes ok", and moves on, even though there are various mystical properties ascribed in pop-sci woo-woo explanations. The one finding of the Wolfram Physics project that made me sit up and pay attention, is that they derived HUP as composed of two different structures of ambiguity (simplifying enormously: across and ancestrally within the branchial space). That sounds ~right to me, and indicates some profound insight they are generating from discrete combinatorial approaches.