Tonight on GeekNights, Rym begins a series of short episodes where he talks about something that's stuck in his craw. Join us in the forum thread to prove him wrong or ask questions. Whatever threads get the most engagement will lead to "part two" episodes of those topics going deeper.
This is why you can't let Scott go out of town. Mods asleep, post quantum physics.
Live Stream:
I think this is a really interesting topic and it was fun to hear some of your takes on it. I’ve similarly grappled with questions of consciousness and what the hell this reality is or means, but usually more from a philosophy angle rather than pure physics (I double majored in computer science and philosophy in college). There are a few things that are stuck in my craw about it, and I’ll sort of spew them out.
Many Worlds
Many worlds seems kind of reasonable when you’re thinking about the interference pattern appearing to photon detectors sort of disconnected from where they’re emitted and then split by the slits, but then there’s the fact that you can recreate the experiment pretty easily and actually see the wave interference. I like the part in this video where she’s tracing the beams back to the point where they split, and she talks about how this made her feel like the wave behavior is real, it’s actually there and you can easily see it; it’s not just an artifact of the math. I have a hard time squaring the raw physicality of the wave behavior here with many worlds.
Broken Causal Chains
You talk about a simpler way of viewing the wave behavior, as broken causal chains where many possibilities are all equivalent because they have the same result. But this is also difficult to make fit with physicality of wave behavior. After all, the wave behavior itself seems to have plenty of causal power; just look at the number of YouTube videos it has caused to be made. This isn’t just the universe saying these things don’t matter. It feels like a more substantive, somehow tangible assertion that certain things fundamentally can’t be known, as if secrets are an actual elementary building block with their own specific behaviors.
Penrose
I think that Penrose is grasping at straws with the whole quantum effects in microtubules in neurons in the brain thing. It doesn’t actually solve the mind–body problem, since nothing in the models physics gives us, be it quantum or classical, requires conscious experience. All the equations of physics could chug right along without consciousness having to exist at all. These models don’t care whether consciousness exists or not; they seem to have nothing to say about it at all. They deal with physical facts, and conscious experiences seem to be a totally different kind of thing entirely. I align with the philosopher David Chalmers on this in that I think the “hard problem of consciousness” is truly hard. We’re probably not gonna solve it by just learning more about physics and biology. I have no idea how we could solve it.
Consciousness as Emergent
I think this is just as much grasping at straws as Penrose’s thing is. Regarding the nature of consciousness, I’ve never been able to get past the cogito. In a very pragmatic sense, consciousness seems more fundamental to me than physical reality. I have direct access to my conscious experiences, but I can only infer the existence of physical reality based on a sort of coherence that those conscious experiences seem to have. Thinking physical things are real certainly has the weight of very strong intuitions behind it, but I question whether it actually stands up to logical scrutiny. So to turn around and say consciousness actually emerges from the physical is just too far. You haven’t even convinced me beyond a reasonable doubt that the physical is really real. How then could it be more fundamental than consciousness?
Science and Causality
Here’s a thing I’m adding to the mix that has seemed problematic to me for a while. Science is fundamentally observational, not predictive. By that I mean that if science makes a prediction and the prediction turns out to be wrong, science doesn’t break, it just changes its models to accommodate the new information. So the latest models always take into account everything that has happened so far. If you play this out to the end of time, science will end up with a model that describes everything that happened throughout all of time to the best of our collective knowledge. We’ll never know whether anything could have happened otherwise, because it didn’t happen otherwise. A lot of scientists seem to just assume a fully deterministic material universe, and discard free will on that basis. But because the commonly accepted definition of free will includes that we could have done otherwise, and we’ll never know whether we could have done otherwise because we’ll only ever know what did transpire and never what could have, we don’t exactly know enough to get rid of free will. Determinism itself seems to be on as shaky ground as free will is.
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I guess the upshot of all this is don’t study philosophy if you actually want to know anything because the more philosophy you study the more your confidence in knowing almost anything just crumbles away into the void.
Caveat: I went to undergrad for physics but wasn’t able to finish due to financial issues, the degree I got later in life were for CS. So I’ve done a lot of the math, but higher level stuff like QM, SR, QFT, QCD, etc. are things that I know the basics of but have not done extensive practice with. So with that here’s my 3rd year physics student’s commentary.
So I think a lot of what Rym spoke about is reasonable from a lay “I’ve never done the math but I’ve read a ton about the subject” understanding of QM. Some of the terms were a bit weird, but overall it jives with my understandings.
I think a lot of what Rym’s final thoughts are pushing more into the higher order effects of QM which really isn’t the study of QM et. al. You’re basically saying that QM gets averaged out at higher orders, which is more or less covered in any course on Statistical Mechanics (also, the most famous text for this subject has the best opening line of any text book
Ludwig Boltzmann, who spent much of his life studying statistical mechanics, died in 1906, by his own hand. Paul Ehrenfest, carrying on his work, died similarly in 1933. Now it is our turn to study statistical mechanics. Perhaps it will be wise to approach the subject cautiously.
)
I think the problem with the idea that all those QM effects completely average out isn’t entirely born out. If you’ve ever done any study of dynamics you get to see equations that are highly sensitive to the initial conditions, even when you do simulations of say the solar system something where we know the current conditions pretty well, the outcomes of the equations can vary wildly even after a few time steps. Chaotic Dynamics is a wild thing to try to study and model ( I did a bit of this for a independent study project because my advisor heard me say I wanted to study particle physics and he, as a condensed matter physicist took offense at that and decided to torture me).
My gut says that over all Rym is probably right, because the number of particles we’re talking about are astronomical and one particle, a million particles averaged out over any given area is still an unimaginably small number compared to the ones around it, but I do quibble with his example. Mostly because the number of particles in that small cm^3 of air above the rink being 5C higher than it should have been is also a huge number of particles that are all doing something together.
I think in the next one I’m going to focus solely on superposition. It’ll be easier for me to prep with the correct terminology 