Comment by FakeComments | Hacker News Reader

Comment by FakeComments | Hacker News Reader

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> I feel like when people say ‘realist’ in this context, they mean someone who believes that ordinary intuitions about the way the world works are how the world must work at all levels.

From the article:

> Like Einstein, Smolin is a philosophical ‘realist’ — someone who thinks that the real world exists independently of our minds and can be described by deterministic laws.

So no, they don’t.

Also, realism is consistent with quantum experiment — non-realism is merely an interpretation that’s had more developers work on it, not somehow a proven component of reality. (Commonly called Copenhagen interpretation; MWI and Bohmian are other interpretations; arguably loop quantum gravity too.)

I agree with Smolin: non-realism is an extraneous assumption meant to preserve locality, but reality is empirically non-local.

Ironically, it’s actually the non-realists who are guilty of what you say — they can’t let go of their Euclidean intuitions, and so come up with nonsense like denying realism. Their entire model is fundamentally predicated on things looking like a smooth Euclidean space at all scales below some threshold — that is, that reality all the way down looks like what we see when we look around.

Non-realists insist on a Euclidean world despite contrary experimental evidence.

If you view energy as distributed across the topology of your space, which often is radically non-Euclidean, you immediately have realism back — the world just is nothing like what’s in front of your eyes. (Enter loop quantum gravity.)

> non-realism is an extraneous assumption

Realism is as much an assumption as non-realism. It doesn't feel that way, because realism fits the common sense of some evolved monkeys. Common sense sometimes is correct, sometimes is not. It doesn't really mean anything when we deal with these matters.

In fact, I would argue that Occam's Razor advises us to prefer non-realism. With non-realism, we are restricted to something we know to exist, by virtue of our human experience: our first-person perception of things. The independent reality, or third-person perspective, is undoubtedly a useful model, but we have no empirical data to suggest it is real. In fact, I would argue that quantum mechanic does raise some serious issues w.r.t. the this model.

Btw, this debate is almost as old as human culture. It was already present in Aristotle (materalism) vs. Plato (idealism). You can also find many traces of it in Eastern thought, e.g. the idea of Maya, or the question of: how can you really know if you are dreaming right now?

> not somehow a proven component of reality

There are no proven components of reality. Proof is something possible in the domain of mathematics, if one accepts certain axioms. Science is not in the business of proving things, it is an empirical endeavor. It gives us theories that resist falsification (until seen) + eternal doubt. Once you abandon doubt, you abandon science.

> Btw, this debate is almost as old as human culture. It was already present in Aristotle (materalism) vs. Plato (idealism).

Materialism vs. idealism is not the same disagreement as realism vs. non-realism. Both materialism and idealism preserve counterfactual definiteness (CFD). The quantum interpretations that give up CFD are a fundamentally new paradigm, and a ridiculous one IMO.

For instance, the mathematical universe hypothesis is a new form of idealism, but it preserves CFD and so is realist.

Thanks you for your reply. I will think more deeply about what you say, but unfortunately I have to work :) A quick reaction follows.

> Materialism vs. idealism is not the same disagreement as realism vs. non-realism.

True, but they are deeply related. Non-realism is only weird if you assume materialism. I'm not sure idealism is sufficiently well-defined that one can say that it preserves (or not) your definition of CFD.

> The quantum interpretations that give up CFD are a fundamentally new paradigm, and a ridiculous one IMO.

How do you interpret delayed-choice quantum eraser experiments? This is not a rhetorical question btw, I am 100% open to reading your take.

> For instance, the mathematical universe hypothesis is a new form of idealism, but it preserves CFD and so is realist.

Only with Tegmarks's later-added assumption that only objects describable by decidable computations are real.

> How do you interpret delayed-choice quantum eraser experiments?

A Bohmian interpretation will suffice to explain how realism tackles it: https://en.wikipedia.org/wiki/Wheeler%27s_delayed-choice_exp...

> In fact, I would argue that Occam's Razor advises us to prefer non-realism.

Can you list these arguments, please? IMHO, Occam's Razor is at side of realism: our Universe has no bounds in space, in time, and in scale. So, we can predict future of any particle if we will have enough information about it, but we cannot do that with 100% confidence, because Universe is endlessly deep. We can only collect information about particles at our "layer" of Universe only (or "dimension" in terms of String theory). The deeper we will go, the more uncertainty we will have, because particles will be influenced by "layer(s)" ("dimensions") below our.

> Can you list these arguments, please?

I can give you mine... Realism argues that we (as minds, let's say) exist within a reality that keeps existing when we are not looking, i.e. that is independent of our own existence. These are two types of entities, mind-body beings such as you and me + the external, persistent material world. If there's just entities like you and me (whatever we are) sharing a collective dream, that is one less type of entity. Occam's Razor advises against the unnecessary propagation of entities in explanatory endeavors.

This of course does not falsify realism, but it demands that it is there only if to explain something that could not be explained otherwise.

> our Universe has no bounds in space, in time, and in scale

Perhaps I don't understand what you mean. I would say that our universe (forgetting MWI stuff) is bounded in time (Big Bang was 13.7 billion years ago), in space (expanding but finite) and in scale (there is such a thing as the fundamental building blocks of matter, maybe they have internal structure, but they seem to be below the level where the concept of "structure" even makes sense -- they are phenomena more than "things").

> So, we can predict future of any particle if we will have enough information about it,

Not really. https://en.wikipedia.org/wiki/Quantum_indeterminacy

> but we cannot do that with 100% confidence, because Universe is endlessly deep.

You are alluding to chaos theory, but quantum indeterminacy is more fundamental than that. Also, nobody knows if the Universe is "endlessly deep", and current empirical evidence points to "it's not".

The very notion of “you and me” is an appeal to realism: without an external world, there is only me — “you” become a figment of my imagination.

Realism explains why my paper a) arrives while I’m asleep and b) sometimes surprises me with the content or by not arriving.

I’ve yet to see a non-realist explanation of my paper that doesn’t seem deeply more convoluted than “someone like me, but not me dropped it off independent of my awareness”.

I’m not saying you can’t make a model out of that, but you quickly arrive at the equivalent of epicycles to explain even basic things like my newspaper arriving (or not).

Also, “quantum indeterminacy” is an assumption, not a proven fact supported by evidence. That’s the exact thing under discussion now: it’s justification as an interpretative assumption.

There’s also an “outside the box” problem: in a non-local universe, it may be impossible for you to compute the trajectory of something without perturbing it, eg, because you slightly jiggle all of the electrons everywhere.

So the co-trajectory of your computation and the particle only ever agree by so much: attempts to increase the accuracy of the calculation kick the particle around, rendering it inaccurate.

There’s deep senses in which uncertainty emerges from being part of the system you’re measuring, in any paradigm.

> With non-realism, we are restricted to something we know to exist, by virtue of our human experience: our first-person perception of things.

Take that to it's logical extreme and you end up with solipsism. Why suppose anything else exists other than your own first person perceptions in this moment? If you allow for other first person perceptions which you don't experience yourself, then why not a world of space and time for those experiences to exist inside of with bodies and everything else that constitutes or supports our first person perceptions?

Alternatively, the non-realists prefer to view the Uncertainty Principle as deeply true instead of seeing Special Relativity as deeply false.

Yes — so much so, they added it as an extra assumption to their model.

The original justification is that we have things like Bell’s experiment that say reality is non-local or non-deterministic, because they exclude local determinism.

But since then, we’ve found increasing evidence that it’s non-local, and so the choice made for the Copenhagen interpretation, to preserve locality at the cost of determinism, becomes unjustified.

It’s now included as an extra assumption out of tradition, and because no one wants to seriously rewrite things. However, as Smolin contends, that may be a dead-end intellectually and an impediment to unifying QM with relativity.

A non-local, but real QM interpretation has a more straightforward paradigm to merge with relativistic gravity: it aligns their models philosophically.

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