Another interesting item that came out the Scott Aaronson thread mentioned in last post was a question to Scott about David Tong’s views on “physics laws can’t be simulated on a computer.”.
It turns out that there an unsolved puzzle that doesn’t allow the Standard Model to be simulated on a computer. I’ll let Tong explain it:
The difficulty lies with electrons, quarks and other particles of matter, called fermions. Strangely, if you rotate a fermion by 360 degrees, you do not find the same object that you started with. Instead you have to turn a fermion by 720 degrees to get back to the same object. Fermions resist being put on a lattice. In the 1980s Holger Bech Nielsen of the Niels Bohr Institute in Copenhagen and Masao Ninomiya, now at the Okayama Institute for Quantum Physics in Japan, proved a celebrated theorem that it is impossible to discretize the simplest kind of fermion.
https://www.scientificamerican.com/article/is-quantum-reality-analog-after-all/
Scott mostly dismissed the problem at first as a technical matter, but then later found the topic intriguing and one he might later post on. He still thinks its a technical; matter however, if it isn’t just technical it would mean:
“Reality is ultimately analog rather than digital. In this view, the world is a true continuum”.
Prasanna who posed the original question provided a video link. While I’m not a fan of videos, I found this one particularly interesting. The core explanation begins around 24 minutes, but there is a lot leading up to it, some of which I will need to listen to again. By the way, some of the question at the end are also really interesting.
The answer to whether we are living in a matric would be “no” if reality is analog. More correctly, it should be said we would not be living in a digital simulation.
A couple of things that caught my attention even though they are probably well-known to many.
Protons are an emergent phenomena. They emerge actually from thousands of quarks, but there happens to be small difference in the types of quarks and that number is usually what people use when they talk about the number of quarks in a proton.
Photons and gravitons are both massless. This allows them to travel at the speed of light. Odd isn’t it that the particle of gravity itself has no mass? Also, so interesting that gravity and the speed of light both have such prominent roles in Relativity. Is there some deeper connection?
The way he described reductionism made it seem to me that it might be better called “constructionism”. We can derive larger things with smaller things (although even that is practically impossible in most cases), but we can’t go the other way. We can’t look at the big things and derive the small things.A corollary is effects of the smaller things wash out as things get bigger. This is usually stated in the context of quantum fluctuations, but it might be more universally true. For example, we can derive biochemistry from chemistry but we can’t derive chemistry from biochemistry.
Broad Speculations 
Very interesting. I am still waiting for someone to explain how time is a dimension, how it can be welded to space dimensions, and how it can expand and contract, as if it were a thing. So many strangenesses, so little time!
Thanks, James!
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Yeah, time doesn’t seem like a dimension sometimes to me either.
Sometimes I can almost grasp it. I am not sure this is correct, but, since the photon and graviton both move at a finite speed (the same), then time is entangled with gravity which is entangled with space.
If you read this to the end, you noticed something interesting about protons. I know you and I have had discussions about the mysteries of protons before. That the protons is emergent from quarks might expect the mysteries in some way.
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Or, a simpler explanation is that time makes the equations match the results.
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The following is my meagre understanding of ‘Time’ as a dimension:
Space – Time is 4 dimensional. Space is 3 dimensional – length, breadth and height. Time is the 4th dimension. There is no gravitational force in Space – Time. Gravitational field is actual Space – Time (curved) and the electromagnetic field is located within it.
‘Time is nature’s way of ensuring that not everything happens at once’. Our current reality is here; in a cross-section of time from a 5th dimensional vantage point. Could God (or The Logos according to Greek Philosophy) be that which created time – life?
Without mass travelling through Space then there would be no time to observe. Mass that is not moving is not creating time. So if everything stood still and the Earth stopped rotating at midnight then there would be no time.
Mass needs Space to travel in, so that we can measure and label it. If not, everything would exist in the eternal – here and now.
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“Gravitational field is actual Space – Time (curved)”
This is what I was trying to get at.
I’m not sure you’re right but your explanation sounds better than mine!
“the electromagnetic field is located within it”
Right. There is in reality only one EM field (its particle the virtual photon) – one field for any particle.For example the electron also really has one field with the individual electrons like wiggles in it. I think Tong talks about that somewhere in the talk.
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I am sure that I do not completely comprehend the physics. However, this sounds similar to the epistemological conclusion Hilary Putnam expressed way back in 1981. “There is no God’s Eye point of view that we can know or usefully imagine. There are only the various points of view of actual persons reflecting various interests and purposes that their descriptions and theories subserve.”
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The physics isn’t too dense in the article or the video, but likely you and I for sure will need to read or listen a few times.
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I haven’t watched the video yet but I’ll say some things for now about this in case my answers change.
I begin from the premise that I’m a product of an absolute causal world, and not because I can know this to be true, but rather because if false then it would be impossible to figure things out to the extent of such a causal void. From the position that there is a causal world which produces me, such a world must inherently be a continuum. This is to say that one thing must inherently lead to a causal other from the premise. Here our perceptions of discrete existence should merely be considered epistemic illusions.
So now for this “matrix” business. If they’re talking about the famous movie, strictly speaking I can’t deny the possibility. All of my consciousness (and you’re part of it) could be fabricated by means of messing with my brain to put me in a fabricated world. What I experience would still be real, as well as causal, and even if the things that I perceive don’t otherwise exist (like you). So in that case I’ll say that I’m enjoying my red pill and thus have no need to take a blue (not that I have reason to suspect that you and all the rest are mere fabrications).
What I think they might have instead wanted to reference is whether or not consciousness can exist by means of computer information processing alone. Could I (for example) merely be a product of “ones and zeros” and so have no other substrate from which to exist? My information argument suggests that this is a non-causal position. This might be most concisely illustrated with my thumb pain thought experiment. https://cemifanpage.wordpress.com/2023/11/04/post-4-should-information-need-to-inform-in-order-to-exist-as-such/
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None of this really gets into the topic of consciousness.
Any digital simulation, however, clearly wouldn’t work if reality cannot be broken into discrete units.
But it could be that the distinction between digital/analog, quanta/continuum is somewhat like the wave-particle duality.
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I’ve now listened to the video (while doing mundane things like brushing my teeth, driving, and whatnot). I actually think I nailed it. David Tong gets into consciousness here by trying to address the possibility that he’s “digital” (or you, or I…). Each of us highly doubt this (unlike Elon Musk). I think he made a common technical mistake by referencing The Matrix however. One needn’t be digital in that case since brain based consciousness was displayed in those’d movies. Here digital consciousness is not mandated. If there happens to be a popular enough movie about having your mind/self uploaded to the internet, then I think people ought to start referencing that one to lessen confusion here. Thus there wouldn’t be any brain physics to constrain the digital mind dream. Surely The Matrix people would have gone that way as well, except that it was simply too cool to display wired up bodies for Hollywood to pass.
The way David goes about demonstrating the falseness of a discrete rather than continuous reality, is through some evidence about how things work and lots of esoteric physics and math. Can’t say on all that, but good enough.
I don’t quite demonstrate the empirical falseness of discrete rather than continuous reality. I instead argue that ontologically a continuous reality would be a causal sort, while a digital reality would not be. And of course many would argue that there’s nothing non-casual about reality ultimately existing digitally anyway, so what makes the most sense?
In the end I doubt that either his or my approach will convince many. On this matter people today tend to just believe what they want to believe. Just as we once learned how to make fire however, this situation should change once we learn how to make consciousness. That should tell us if it’s ultimately just made of “ones and zeros”, or rather that there’s a continuous causal sort of physics by which consciousness exists.
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I don’t know that he demonstrated the falseness of discrete reality but he explained a problem where the lattice mathematics used for quantizing doesn’t work for a left-handed and right-handed fermions. Until the problem is resolved somehow the Standard Model can’t be simulated on digital computer.
It could even be tied to the problem of why almost all the mass in the universe is matter and there is not an equal amount of antimatter.
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The statement “reality is analog” strikes me as one we can’t make. Reality at the fundamental physics level does seem continuous, but we can’t be sure it isn’t discrete below the level we’re able to measure. The discreteness might be at or below the Planck scale.
But I don’t think it helps with knowing whether we’re in a simulation anyway. Any digital system can simulate an analog one. (You do it every time you stream an old movie.) Even if it were an issue, we can never know when the sim might be lying to us (assuming we’re biological beings in a matrix type environment) or simply not allowing us to perceive any limitations (if we ourselves are part of the sim).
I think our only way to know is if the sim or its owner contacted us directly. Overall I think us living in reality is more parsimonious than us in a sim of that reality, but that’s not the categorical dismissal many are looking for.
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Reality is analog is what Tong is arguing. But only if the described problem doesn’t have a resolution or can be confirmed as a real problem. In that case, we would be sure it isn’t discrete below what we are measuring.
Aaronson thinks the problem will be solved. Somebody else pointed out a proposed solution that involves an additional dimension (also my favorite unconventional solution to where consciousness is located).
The simulation part actually isn’t the main thrust of the article or the video. It’s the physics problem. However, as I commented below, any digital simulation, however, clearly wouldn’t work if reality cannot be broken into discrete units.
Aaronson’s comment on the video:
“It’s a beautiful lecture, clear and full of insights. I’d recommend it to anyone, regardless of what quibbles I have with the broader conclusions that Tong draws”.
But also
“In the end, then, I reject the contention that this is able to tell us much about the truth or falsehood of the simulation hypothesis. And having listened to Tong’s lecture, it sounds like he himself doesn’t take that contention too seriously either (he described his title as shameless clickbait)”!
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