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Philosophers and many scientists seem to distinguish between the macro and micro world a lot. Things in the micro world seem to be indeterministic, atleast through the standard interpretation of QM.

My question is two fold.

A) If quantum events are truly indeterministic and unpredictable, how is it that the probabilities defined in that sphere are of a certain number? Why isn’t there complete chaos?

B) Why or how does quantum indeterminism lead to the laws in which we know the macroscopic world operates in such as the net force on an object being equal to its mass multiplied by its acceleration? Why a particular equation rather than another one?

In other words, why is there not complete chaos if at the most fundamental of stages, there is a lack of deterministic behavior? Is it at all possible that we could be wrong about this indeterminism? (Although I suppose even if the universe was deterministic, it would beg the question of why those deterministic laws are there, but that seems to open up fewer questions)

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    This is a question for a physics forum. Commented Sep 10, 2023 at 2:27
  • @DavidGudeman, Sean Carroll isn't on Physics SE. thinkingman is in No Man's Land. Let's accommodate him on Philosophy SE ... please.
    – Hudjefa
    Commented Sep 10, 2023 at 5:08
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    This is the well-known quantum decoherence effect: If it is not perfectly isolated, for example during a measurement, coherence is shared with the environment and appears to be lost with time; a process called quantum decoherence or environmental decoherence. As a result of this process, quantum behavior is apparently lost, just as energy appears to be lost by friction in classical mechanics... Commented Sep 10, 2023 at 6:42
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    @AgentSmith, about half the questions on here are asked by thinkingman, and almost all of them are minor variations on questions he has asked before. He is making the site unreadable. Commented Sep 10, 2023 at 7:32
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    @DavidGudeman, you didn't have to, but merci beaucoup for clarifying. Now that you mention it, he does post a lot of questions. I did a survey of past unanswered questions and they seem to be high quality research level ones. It just shows in the language & concepts alluded to. I suppose Philosophy SE has its ups and downs.
    – Hudjefa
    Commented Sep 10, 2023 at 8:51

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Quantum mechanical theories are heavily probabilistic. That doesn’t mean it’s hard to make predictions at the macroscopic scale.

Casinos also rely heavily on probability, yet they get by just fine. They don’t know which tables, slots, or hands will win. They only have probabilities. And would it actually matter to them whether their slot machines are indeterminant at their core or totally deterministic with the same probabilities? Nope. They can get by either way. What they would never do for indeterminancy is tie a single radioactive atom’s decay time to a jackpot. But aggregate a few million indeterminate radioactive atoms and it’d be fine for them and their underwriters.

It might surprise and help you that only two out of about two dozen main quantum theories are strictly indeterminate ontologically, and really only one is indeterminate in a totally strict sense, the Ghirardi–Rimini–Weber interpretation of the measurement-problem. Copenhagen/textbook QM is so sparse on ontology it doesn’t actually say enough ontologically but is counted usually. But all two dozen, indeterminate or not, are just fine for the Casino to make money.

All the buildings in Manhattan aren’t each tied a to different atom’s radioactive decay, waiting to be demolished when they do decay. Our macroscopic world is not built like that. It’s mainly the macroscale stability from statistical mechanics. That’s an equal pillar to QM and GR to why the world is as such. It has a huge role.

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The reality is indeterministic. Only the laws describing how it works are deterministic. Indeterministic reality does not lead to deterministic laws, the laws are human written.

The laws are slightly inaccurate as they deal with approximations and averages instead of absolute values. But they are still accurate enough for most practical purposes.

Indeterminism does not mean total chaos, as you can see. Indeterminism means only the absence of determinism, which means that:

  • Events are not completely determined by the previous event. There is no such thing as absolute accuracy.
  • Some events (voluntary actions) are determined by the agent's decision to act. A decision is not a physical event.
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In my view indeterminism is simply used as a "God of the gaps".

There's no positive evidence of indeterminism. In fact, it's not even clear how indeterminism is compatible with scientific enquiry or human reason, since those assume determinism as their tenets.

What there is, is an absence of any clear mechanism that governs the workings at the "micro" level in a deterministic way. There isn't an absence of imagination of how things might work, but there's an absence of a fully worked-out theory and proof of it.

This absence of extant theory and proof is not the same as proof that there is no possible theory. All accepted science has passed through a stage where humanity didn't quite understand how things worked.

So this absence alone is not a good reason for thinking that things work differently at the micro level or that determinism ceases to apply.

We also shouldn't be surprised that progress is slow in this area, since so many so-called scientists have counselled themselves into a condition of learned helplessness, where many are not even theorising anymore about how the "micro" world may work in a deterministic way.

Effectively, those who reject determinism are actually anti-science - or at least, they are deadweight scholastics who retard the advance of science by typically heckling those who want to investigate or propose any new explanation of a deterministic kind, for no better reason than that no existing authority was aware of such a new deterministic explanation.

American science in particular has always been hostile to any developments in this area, because they have a dominant political ideology which lauds individualism and a semi-religious attachment to "free will".

They are hostile to explanations of human behaviour that don't localise to the individual, because the implication of explanations being non-local to an individual is that, when there is dysfunction in individual behaviour, you have to change the relations between individuals or alter something about the political environment.

It may seem tenuous, but for them, the idea that the brain relies on this "micro" world where things work differently and where effects don't arise from causes, is just what they need to keep talking about free will (and even divine intervention), and to keep the discussion off broader political change.

As for how they justify "macro determinism" from "micro indeterminism", the primary device seems to be that statistical analysis (and the observed statistical regularities) is asserted to be compatible with indeterminism.

It's not quite clear why this should be the case. By definition, we cannot analyse the indeterminate world in order to arrive at an explanation of why statistical regularities occur in the effects which originate from there. I suspect this is simply offered as a just-so explanation of how the world works, without any deeper justification for why an indeterminate world should be statistically regular.

To ask such a question is already to lapse back into the enquiring determinist mindset, of asking how an effect is justified by some cause.

The determinist, of course, would say that statistically regular effects arise from statistically regular causes, and since causes relate to effects in a consistent way, that is what answers the deeper "why" question of why the effects are regular.

We use statistics extensively to analyse deterministic situations - there's nothing about using statistics that implies indeterminism or requires indeterminism.

The application of statistics to QM is the sole case where statistics are said, by some, to be applied to indeterminism.

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