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Comment by davesque | Hacker News Reader

Sort of off topic, but sometimes pondering these low-level physics questions forces me into a philosophical state of mind. It seems like asking questions about basic particles is representative of a mode of thinking that drills down ever further, trying to find some kind of conceptual bedrock. But it always seems possible to ask again, "What lies underneath this? What is the cause of this thing's existence?" In any case, it seems either that you have found the one thing that underpins everything else or you have found the collection of things that all endlessly perpetuate each other. Both of those possibilities seem somehow unsatisfactory or impossible. There must always be something else. Could it be that this conceptual craving is somehow just a side effect of how our minds are built? Or is it fundamental to reality in some way?

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I don't know, but let me point the obvious: it feels very weird that fundamental things are so complicated.

Somehow I want to think that there's a much simpler layer underneath and all this imperfection comes as a second order side effect.

Plato's cave seems the relevant meme. But is it really complexity a side effect or, as you suggest, is simplicity a side effect of our minds' pattern matching preferences?

I can sympathize with this. I love discovering some generalization that subsumes all the complexity. But what if we follow this to its extreme? Suppose we find the one perfect symbol that precipitates all other concepts? What then does that symbol even do but just reflect or perturb its environment? Isn't that just like moving the goalposts? Makes me think of the concept of Kolmogorov complexity. That's the idea that the informational content of some signal is equivalent to the length of the shortest computer program that can produce it. But what interprets the program? And how complex is that thing? It's all circular. And I'm not sure there's really a way out of that. It's just an inherent feature of looking at the universe conceptually.

This evokes thoughts of 3-LISP and what is, to me, one of the most compellingly titled papers in CS: "The Mystery of the Tower Revealed"[0]

[0]https://dl.acm.org/doi/10.1145/319838.319871

> is simplicity a side effect of our minds' pattern matching preferences?

That's a good point and I tend to think so. Think about this: pretty much everything (any object or property we observe) is an abstraction. People talk about people who are bad at abstracting and we know what they mean, but actually everyone is abstracting everything. Our actual experience without abstraction is just a bunch of unassociated colors and sensations and whatnot.

The thing that really matters when breaking thing apart into ever smaller things is not really if we are accessing ever deeper level of reality.

What matters is: can we use this newly discovered sub-structure to do something we couldn't before.

The answer to this was a clear and resounding "yes" when we reached the level of molecules (chemistry, which allows us to do a great many useful things), still "yes" at the level of the atom (atomic energy, transistors, etc...).

It is however unclear that QCD, quarks and inner proton structure reality level have yet produced anything usable to implement our will upon the world.

It may yet happen, but to answer your questions: once the depth we dig at stops producing anything usable by an engineer (string theory, quarks both currently fall into that bucket I think), not entirely sure the digging is philosophically valuable in any way.

I think your reply gets at the answer to my own question that I tend to lean towards. And that is that craving further concepts is an inherent problem that follows from being a thinking being. What you say seems like part of the answer, which is that one needs to make a conscious decision not to be bothered by the fundamental lack of a justification for reality. Just focus on what your knowledge enables you to do. But it still seems sad on some level that we're "condemned" to coast through this world that is so rich in detail but seemingly lacking in purpose.

LEDs and most modern microprocessors make no sense without quantum mechanics, for one.

Neither do magnets.

Not sure why you would bring that up.

I never said quantum mechanics was useless.

That's actually specifically why I mentioned transistors.

However, I don't believe QCD has yet produced anything tangibly usable to do stuff in the world.

The proof is in the pudding: if QCD ever does produce something useful, I'll happily recant.

But my general point was that as we dig deeper and deeper, what we get is exponentially diminishing returns, up and until the point when we'll research stuff that's maybe logically coherent, intellectually satisfying but plainly useless, just like string theory currently seems to be.

Ah, I misunderstood and phrased it badly.

My point was that when quantum mechanics first was proposed early last century, I can’t imagine anyone would have even considered LEDs as a thing even in their wildest dreams, yet it was obvious once further progress occurred, and was key in understanding and developing them past the initial ‘that’s odd….’ stages.

We don’t know yet if something similar will come out of QCD (understandable and usable ‘high temperature’ superconductors? Quark matter computers? Super high strength materiel derived from some kind of degenerate matter?) but it definitely seems less likely by the day.

It does at least have falsifiable predictions, so it’s about a billion miles ahead of string theory!

It’s also possible we’ll need another 50 years of engineering or a world war (I hope not) to dig deep enough into areas to discover another, simpler, way to think about it that is more useful.

I think you may have some hindsight bias here. I do not think that when chemical and atomic structures were discovered/understood that knowledge was immediately put to use. Nuclear physics dates back to the late 1800s, it wasn't until the 1940's where that knowledge was put to practical use. I wouldn't expect anything different with QCD. In fact, I would expect it to take significantly longer to develop practical applications of the theory given how much more complex it is.

Fair point, not knowing when something might come in handy.

I still believe looking for things we can use should be a guiding light.

Very limiting to couple the pursuit of knowledge to application, commercial exploitation, or laying our "will" on the world.

>commercial exploitation

Why would you bring that into the conversation?

Did I mention anything about money?

> Very limiting to couple the pursuit of knowledge to application

Didn't say that either.

I said "useful", and what I meant was "can the knowledge gained be used by us to implement change now or at some point in the future".

As pointed out by another poster, the interesting talking point is that it is hard to guess beforehand whether knowledge gained will ever be useful.

I nevertheless believe in the principle that research should be directed by the hope of discovering something useful, not by the mere pleasure of finding some sort of satisfying "explanation" to the way things work.

But hey, if mine does satisfy you, please let us know what criteria you would use to discover when you've squarely left the area of worthy research to enter that of intellectual onanism.

There are books on the topic e.g., "The End Of Physics" by D.Lindley.

There are two questions:

- whether there are laws that describe everything there is to know (e.g., the answer is yes for chess—there are rules that describe it). It is the "fundamental" dimension (particle physics at the moment)

- whether there is something to do once we know all the laws. The answer is yes ("knowing rules do not make you a grandmaster") e.g., we likely know all of the fundamental physics required for turbulence or brains but it doesn't solve these fields (there are interesting unresolved problems). It is the "applications" dimension.

https://www.quantamagazine.org/contemplating-the-end-of-phys...

The never-ending chain has bothered me too. I realized that if there is a theory of everything, it needs to prove itself. As far as I know, that’s a logical contradiction. Maybe resolving that contradiction is the door to moving forward. Is the concept of a “theory of everything” invalid? Is modern logic insufficient to find it?

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