Ontology is to quantum theory what hardware is to computation theory

[Demystifier]

In interpretations of quantum mechanics there are two types of physicists: those who care about ontology and those who don't. The ontologists, or realists, want to know what is the world made of. The non-realists, on the other hand, think that this question is not relevant to physics.

Usually the two types of physicists don't understand each other. A realist can't understand how a physicist may not care about what is the physical world made of. A non-realist, on the other hand, can't understand how a serious scientist may care about the metaphysical notion of "reality" that does not have any practical consequences.

To help mutual understanding between the two types of physicists, I would like to propose an analogy, or at least a good metaphor. The two types of physicists are somewhat like the two types of computer scientists; those who care about hardware and those who don't.

Suppose that you ask how a computer program works. There are two kinds of explanation one can give to you. One explanation is something like - there is an electric current flowing through the microchip, which consists of many transistors, where each transistor is made of silicon in a pnp configuration, ... This explains how the computer works at the hardware level. The other explanation, on the other hand, will completely ignore the hardware and explain you the algorithm of the specific computer app; it explains how the computer program works at the software level.

The software guy will tell you that it is the computation algorithm that really explains how the program works, while the hardware implementation is not really important for understanding from the point of view of computation theory. The hardware guy will tell you that only understanding the hardware gives you the true understanding how the computer really works. The hardware guy gives you an ontological explanation, while the ontology is irrelevant to the software guy.

Of course, both the hardware guy and the software guy are right in some sense. And more importantly, there is no really any controversy about that, it's not that hardware guys and software guys don't understand each other. They only put more emphasis on different aspects of computation theory, which are complementary to each other.

Likewise, I believe, that two ways of thinking in quantum foundations are also complementary to each other. Realists and non-realists in quantum theory are analogous to hardware guys and software guys in computation theory. I believe that this way of thinking about realists and non-realists can help in better mutual understanding between them.

 

[Halc]

In interpretations of quantum mechanics there are two types of physicists: those who care about ontology and those who don't. The ontologists, or realists, want to know what is the world made of. The non-realists, on the other hand, think that this question is not relevant to physics.

I disagree on just about every level.
"In interpretations of quantum mechanics": Interpretations are by definition philosophy, different metaphysical ways of looking at the exact same things, none of which differ in empirical physics. Those that don't care spend little if any time considering interpretations. "Those who care" might have stronger opinions about this or that interpretation.
"The ontologists, or realists": You make this sound like "those that care" are necessarily realists. For instance, I personally care, and happen not to be a realist. There are non-realist interpretations, so to label anybody who has a metaphysical opinion as a 'realist' is wrong.
The last line is wrong as well. Even "those that care" (be the realist or not) should realize that the question is not relevant to empirical physics. The question is a philosophical one, and those that care should know this, even if a layman might not.

Usually the two types of physicists don't understand each other.

Nonsense. I can understand why some don't care. It really has no practical relevance to one's work. Likewise, those that don't care probably can see why others would find the interpretations interesting. The claim that either side cannot understand the other probably needs references, because I certainly don't see it.

The hardware guy will tell you that only understanding the hardware gives you the true understanding how the computer really works.

You had asked how a particular program works, not how the computer works. They're answering different questions, but both questions are empirical ones, neither being philosophy. I think a better analogy is needed, but I doubt one will be found with plausible "neither side understands the other".

 

[Demystifier]

Those that don't care spend little if any time considering interpretations.

You misunderstood me. I am only considering people who care about interpretations. But among them, some don't care about ontology. Examples of those who care about interpretations but not about ontology would be those who like interpretations such as QBism, relational interpretation and statistical ensemble interpretation.

 

[Demystifier]

I think a better analogy is needed

Sure, this analogy is far from perfect. Have you got a concrete idea for a better one?

 

[Demystifier]

You had asked how a particular program works, not how the computer works.

The hardware guy may argue that you can't understand how any particular program works if you don't understand how computer works. Likewise, a realist may argue that you can't understand how any particular quantum system works if you don't understand what's the ontology behind the quantum formalism. The computing algorithm is analogous to the quantum formalism. The hardware needed for physical realization of the algorithm is analogous to the ontology needed for physical realization of the quantum formalism.

 

[hutchphd]

You misunderstood me. I am only considering people who care about interpretations. But among them, some don't care about ontology. Examples of those who care about interpretations but not about ontology would be those who like interpretations such as QBism, relational interpretation and statistical ensemble interpretation.

As far as I am concerned the original post talks essentially about "religion" and this quote talks about "dogma". I find the first mildly interesting and the second very much less so.

 

[Demystifier]

As far as I am concerned the original post talks essentially about "religion" and this quote talks about "dogma". I find the first mildly interesting and the second very much less so.

Let me guess! You have looked into this thread because from the title you thought that you will learn something about computers.

 

[hutchphd]

Point taken.
Honestly I feel like it should be interesting and hope springs eternal! But I have a low threshold for the arcane. My apologies.

 

[TonyStewart]

Ontology (derived from Wiki )

Can you list the top facts and stats about Ontology?

1. Ontology is the branch of philosophy concerned with being and existence.
2. It examines the nature of reality and what exists.
3. Ontology asks questions about identity, causation, and possibility.
4. The term "ontology" comes from the Greek words "ontos" (being) and "logos" (study).
5. Ontological arguments for God's existence have been debated for centuries.
6. Some philosophers argue that ontology is a fundamental part of all philosophical inquiry.
7. Ontology has applications in computer science, linguistics, and cognitive science.
8. Heidegger's ontology emphasizes the importance of human existence ("Dasein").
9. Quine's ontological relativity suggests that our understanding of reality is shaped by language.
10. Many contemporary philosophers reject traditional metaphysical claims made by ontologyQuantum Mechanics (derived from Wiki)
1. Quantum mechanics describes physics at the atomic scale.
2. It was developed in the early 20th century.
3. Quantum mechanics challenges classical physics.
4. Particles can exist in multiple states simultaneously (superposition).
5. Measurement affects the state of particles (observer effect).
6. Entanglement allows for instantaneous communication between particles.
7. Quantum computing could revolutionize technology and cryptography.
8. The uncertainty principle limits our ability to measure certain properties.
9. Schrödinger's cat is a famous thought experiment illustrating superposition.
10. Bell's theorem shows that quantum mechanics cannot be explained by local hidden variables alone.

Which ones have meaningful analogies?
some, Not many

But consider analogies of consciousness

Can you list the top facts and stats about Consciousness?

1. Consciousness is subjective and cannot be directly measured.
2. The brain's default mode network is active during self-reflection.
3. Studies suggest that animals possess some level of consciousness.
4. The hard problem of consciousness remains unsolved by science.
5. Meditation can alter states of consciousness and increase well-being.
6. Anesthesia disrupts neural activity associated with conscious awareness.
7. Near-death experiences may provide insight into the nature of consciousness.
8. Different regions of the brain are involved in different aspects of consciousness.
9. Consciousness may arise from complex interactions between neurons and synapses.
10. Some theories propose that consciousness emerges from quantum processes in the brain.

again not many analogies.

AI disclaimer:
The summary from the wikiwand site uses an OpenAI API to list these summary items. References are at the bottom the link.

Google has just announced Google I/O using GPT their own AI used in their search engine maps, email etc etc. to compete with Micro$oft

 

[Halc]

You misunderstood me. I am only considering people who care about interpretations.

Ah, I did misunderstand that. I thought the distinction was between those caring about interpretations vs the shut-up-and-calculate types. Most of what I said still applies.

But among them, some don't care about ontology. Examples of those who care about interpretations but not about ontology would be those who like interpretations such as QBism, relational interpretation and statistical ensemble interpretation.

The non-realists are still taking an ontological stance. I for instance lean mostly to the relational side of things, and ontology is very important, perhaps a primary focus, hardly something I don't care about. I do understand a realist stance, but I see problems with it is all. I don't think one can justify any disagreement with a stance that they don't understand.

Sure, this analogy is far from perfect. Have you got a concrete idea for a better one?

Your analogy was between a low level description vs a high level one, sort of like trying to explain how an oil pump works in terms of quantum field excitations. I think a better analogy would be another one where there are competing interpretations, such as that between eternalism and presentism. Now I've seem arguments for the latter based on a complete lack of understanding of the former, but that wasn't from somebody who knew their stuff as would a physicist.
Anyway, the analogy is similar, and yet entirely independent of one's QM stance.

The hardware guy may argue that you can't understand how any particular program works if you don't understand how computer works.

Then he'd be wrong. The program can work on a wooden computer, or on a paper/pencil system. The software algorithm is entirely independent of the hardware on which one might choose to run it.

10. Many contemporary philosophers reject traditional metaphysical claims made by ontology

There are ontological claims made by various metaphysical models, but ontology itself doesn't make claims. I thus find this point poorly worded.

The list for QM is just that, not a list for interpretations of QM, but a list of QM theory itself.

 

[vanhees71]

For me "ontology" is to "quantum theory" (understood as a natural science) like "astrology" to "astronomy". SCNR.

 

[martinbn]

In interpretations of quantum mechanics there are two types of physicists: those who care about ontology and those who don't. The ontologists, or realists, want to know what is the world made of. The non-realists, on the other hand, think that this question is not relevant to physics.

I disagree with this. All physicists seem to care what the world is made of and are interested in studying that. For example it could be atoms. Later when they find out more about the world it could be electrons and protons, or all the particles in the standard model, or fields, or strings,...

The diffrences come when some of the foundation of QM community start to use the words in a different way. Instead of "what the world is made of", they ask "is position real" or "are trajectories real" or "is any other observabla or all observables real". This is when some say well that is pointless. What does it even mean? You (the community) explain "position is real" means that observable has a definite value at all times reagradless of any measurments. Then they say "ah, ok, well, no it doesn't according to the standarad interpretacion of QM". The you say that that is an antirealsit position. Fine, but then you change the meaning again and start saying that antirealist say that nothing exists! When they clearly say that say electrons exist, their positions don't unless you measure them. The nyou obsess about nonlocality. Where the term itself can mean at least three different things and you change between them as you wish.

 

[hutchphd]

This entire discussion, it seems to me, devolves to repeated statements by each side of "Yes, but what does it really mean?". Thence follows more unfettered discussion. If I could see the goal, or a path to the goal, or a path to the path to the goal, I would be more enthused. The subject provides an interesting performance by very bright folks but seems strangely inutile. I have the same response to religion so perhaps it is just me......

 

[vanhees71]

There is no goal in philosophy. It's just a game with words without much "real" (pun intended) gain of knowledge about the natural world around us.

 

[gentzen]

There is no goal in philosophy. It's just a game with words without much "real" (pun intended) gain of knowledge about the natural world around us.

There is no goal in mathematics either. It's just a game with symbols without much "physical" content.

 

[vanhees71]

True. So what?

 

[gentzen]

For me "ontology" is to "quantum theory" (understood as a natural science) like "astrology" to "astronomy". SCNR.

In the end, the word or concept "ontology" is used in philosophy with specific expectations and meanings, basically those quoted in the reply by TonyStewart. The analogy used by Demystifier is simpy very bad at capturing any of those meanings. From my perspective, a programming language typically has a syntax, and a semantics. And the semantics normally also has some ontology, but the physical hardware is not that ontology, at most certain aspects of the physical hardware may form part of the ontology.

The relation of the philosophical concept "ontology" to philosophy or "physics" has no similarity at all to the relation of "astrology" to "astronomy".

True. So what?

I am a mathematician (by training and by heart), so I am allowed to ridicule mathematics. Are you (or Demystifier) philosophers in similar ways that justifies such statements about philosophy (or philosophical concepts)?

 

[pinball1970]

Let me guess! You have looked into this thread because from the title you thought that you will learn something about computers.

I always read these threads because I want to know what this means to scientists, physicists and mathematicians in particular.

 

[malawi_glenn]

There is no goal in philosophy. It's just a game with words without much "real" (pun intended) gain of knowledge about the natural world around us.

What is knowledge? Is it a physical quantity? In what units do we measure it in?

 

[Structure seeker]

Interesting discussion. I myself am very fond of knowing how the "hardware" works, and I've just come to wonder about whether the phenomenon of entanglement is due to how the wavefunctions of quantum information are "objectively defined". In the paper "A system's wave function is uniquely determined by its underlying physical state" [1] it is concluded based on free choice that interpreting the wavefunction as an objective reality is possible regardless of all the probability involved (contrary to a classical or hidden variable state of a quantum property as proven by the Bell tests). The article poses a thought experiment with an info set $\Lambda$ of complete knowledge of the starting setup, consisting of wavefunctions etc.

Then for instance, it would be easy with two photons ~100% entangled in polarization to explain it such that the wavefunction of polarization of both photons is determined ~100% by the same subset of $\Lambda$.

 

[hutchphd]

What is knowledge? Is it a physical quantity? In what units do we measure it in?

The subject was specifically "real" knowledge of the physical world. Knowledge is understanding gained through learning or experience.
I measure it in units of personal utility: it is objectively quantifiable in that regard IMHO. (or was your question rhetorical?)

 

[malawi_glenn]

The subject was specifically "real" knowledge of the physical world. Knowledge is understanding gained through learning or experience.
I measure it in units of personal utility: it is objectively quantifiable in that regard IMHO. (or was your question rhetorical?)

That was a very philosphical answer ;)

 

[Fra]

Likewise, I believe, that two ways of thinking in quantum foundations are also complementary to each other.

I agree. I think one could reflect upon this in different ways. From my own stance of a learning/evolving agent that does inference in its environment, I associate the complementary views with

Ontology ~ the agenta evolved "map" of the "world". This is "real", but observer dependent. The ontology itself implies a rational expectation of the world, which in turn influensea the agents actions and interactions - so it DOES "make a difference".

Epistemology ~ the inference system by which the ontology is motivated and evolving!

So none makes sense to me w/o the other. w/o epistemology/empirics the ontology becomes unconstrained and requires ad hoc finetuning.

Similarly w/o ontology the result of the inference has no physical representation and cant be encoded. It becomes as fictive or abstract as an algortihm that cant be implementes anywhere.

/Fredrik

 

[Fra]

There is no goal in mathematics either. It's just a game with symbols without much "physical" content.

I often think of the goal of mathematics as a way compressing abundant diverse qualitative patterns by simple rules sometimes at the expense if time. For example replace a table with a rule for computing it. Or replace huge amounts of empirical data with timeless laws and initial conditions.

What is more efficient depends on memory and accesstime vs computational time. So math may have a survival value at times?

/Fredrik

 

[Demystifier]

There is no goal in philosophy. It's just a game with words without much "real" (pun intended) gain of knowledge about the natural world around us.

Someone in humanities could strike back as follows. There is no goal in physics. It's just a game with equations and experiments without much "real" (pun intended) gain of knowledge about the human world inside us.

 

[Demystifier]

In the end, the word or concept "ontology" is used in philosophy with specific expectations and meanings, basically those quoted in the reply by TonyStewart. The analogy used by Demystifier is simpy very bad at capturing any of those meanings.

Same words have different meanings in different contexts. "Ontology" in general philosophy is one thing, "ontology" in general quantum foundations is another thing, and "ontology" in the PBR theorem is a yet another thing. My analogy, indeed, does not capture the meaning of "ontology" in general philosophy, precisely because I wanted to capture another meaning, the one in general quantum foundations.

 

[Demystifier]

For me "ontology" is to "quantum theory" (understood as a natural science) like "astrology" to "astronomy". SCNR.

Just the opposite. The goal of astrology is to make measurable predictions that have a practical value, by following a set of rules which are not explained by anything deeper or more general than this set of rules itself. When you ask them why do they follow this set of rules, their answer is - because they work. The astrology, in this sense, is very much like the shut up and calculate approach to quantum mechanics.

 

[vanhees71]

You describe astrology accurately but that's exactly not what's done in physics and theory building in physics, which is based on empirical facts and not some epistemological prejudices. If the latter approach is applied, nothing fruitful comes out (e.g., Einstein's search for a so-called "unified field theory" or in more modern times string theory). It's even worse with philosophy. I've not a single example, where philosohpical reasoning has brought any progress in the natural sciences. There's the incomprehensible ineffectiveness of philosphy in the natural sciences (Weinberg)!

 

[Demystifier]

I've not a single example, where philosohpical reasoning has brought any progress in the natural sciences.

Sure you do. For example, when Einstein simplified the reasoning of Lorentz, Poincare and others by postulating that there is no aether, it was a philosophical reasoning.

 

[gentzen]

It's even worse with philosophy. I've not a single example, where philosohpical reasoning has brought any progress in the natural sciences. There's the incomprehensible ineffectiveness of philosphy in the natural sciences (Weinberg)!

But philosophical reasoning has undoubtedly lead to significant progress in structural sciences, and those in turn were undoubtedly instrumental to progress in natural sciences. You can have a look at some examples I gave for this, and also at the examples and defences of philosophy (in this respect) by other mathematicians here:
https://mathoverflow.net/questions/182215/has-philosophy-ever-clarified-mathematics/182774#182774

 

[Fra]

theory building in physics, which is based on empirical facts and not some epistemological prejudices.

Do you reallly think there is no epistemological prejudices in theory building? I think the idea that all agents infer "empirical facts" in the same way is illusionary.

How can we make say, noise rejection, without epistemological prejudices? For me the current state of the theory IS the "prejudice" and I don't think a prejudice is necessarily irrational. On the contrary, I think the illusion that an ideal theorist has no prejudices at all as naive and fictive.

/Fredrik

 

[vanhees71]

I only say that everything that is not founded in sufficient empirical input is highly unlikely to provide any insights in the sense of natural science.

 

[Fra]

I only say that everything that is not founded in sufficient empirical input is highly unlikely to provide any insights in the sense of natural science.

I can agree to this, but for me the solution is no to be "free of prejudices", but to entertain somewhat rationally evolving prejudices (which I think should be empirically constructed). This is exactly the reason why I seek "constructable theories" withing the context of realistic inference, meaning subject to realistic constraints of an agent, such as limited information capacity.

This was also what I meant in post 23. The two views are not in contradiction, they may even interact. And for me this is an insight. We shouldn't bash one or the other, but perhaps seek to understnad how they support each other. The complementary views are almost like a bootstrapping in the problem of theory building, where one often needs to motivate the primary notions.

/Fredrik

 

[Demystifier]

All physicists seem to care what the world is made of and are interested in studying that.

Only to the point. To demonstrate this, let me present a typical dialogue between a "realist" (R) and a "typical physicist" (TP) how I see them.

TP: The world is made of atoms, which are made of finer objects such as protons, neutrons and electrons.
R: Sure, but what these objects are? For example the electron, is it the same thing as its wave function?
TP: To the best of our knowledge, yes, the electron is nothing else but a wave function.
R: And when we measure the position of the electron, the wave function suddenly collapses, right?
TP: Yes, that's how we describe it.
R: But is the collapse something that really happens?
TP: Well, if we take it literally, then it violates the Schrodinger equation and the principle of locality. So that's probably not what really happens.
R: So what really happens?
TP: We don't know.
R: Fair enough. But do you care about what really happens?
TP: Not really, because this is a philosophical question that currently cannot be decided by an experiment.
R: So you don't really care about what happens with the electron when it is measured?
TP: I care about those aspects which can be decided by measurement, and don't care about those that can't.
R: Right! And since, as you just said, the answer to the question "what really happens with the electron when it's measured" cannot be decided by measurement, it follows that you don't care about this question.
TP: Yes.
R: Fine, but let us also consider the opposite question: What really happens with the electron when it is not measured? By definition, the answer to this question also cannot be decided by measurement, so you don't care about this question either.
TP: Right.
R: But the electron is either measured or not measured, there is no third possibility. Hence you don't care about what really happens with the electron at all, under any circumstances.
TP: Yes, the question "what really happens" is metaphysical and I don't care about metaphysical questions.
R: Fine, so the question "What happens with the electron?" is metaphysical. Is the question "What the electron is?" equally metaphysical?
TP: Yes, it's a question of the same kind.
R: And hence you don't care about the question "What the electron is?".
TP: Exactly.
R: So you care to know that the world is made of electrons and other stuff, but you don't care to know what the electron and other stuff is.
TP: Yes. Well, no. This discussion doesn't make sense, it's just empty philosophy playing with words, and I don't care about philosophy.
R: Fine. And the question "What is the world made of?" is a philosophical question, so you don't care about this question.
TP: This question has scientific and philosophic aspects. I care only about the scientific ones.
R: Good. But from the purely scientific point of view, you cannot say what is the world made of when we don't measure it, because science is based on measurement. Therefore you don't care about the question what is the world made of when we don't measure it.
TP: Yes.
R: But the world is made of something, irrespective of whether we measure it or not. The measurement disturbs its behavior, but the stuff it is made of is the same, whether we measure it or not. Would you agree?
TP: Yes, that's probably true.
R: So you don't care about the stuff the world is made of.
TP: True, because it's a philosophical question.
R: I rest my case.

 

[vanhees71]

The assumption of what's (very unfortunately) called "local realistic theory" is founded solely on prejudices, originating from the belief that our everyday experience with macroscopic matter which lead to very successful classical models for the observed behavior of this matter. Particularly calling only such a "local realistic theory" "complete" is a big prejudice.

On the other hand in 1925/26 modern QT was discovered (based on empirical facts such as the black-body spectrum, the photoelectric effect, Compton scattering, discrete optical spectra related to "atomic structure",...), which clearly contradicts the "local-realism paradigm". There was from 1935 on a very fruitless debate around the EPR paper. It was fruitless, because it wasn't based on clear empirical facts but on the said epistemological prejudices of EPR.

From a scientific point of view the real breakthrough were Bell's ideas, how to test empirically the assumption of "locality and realism" a la EPR, i.e., he made the vague philosophical ideas a precise quantitative predictions about empirical facts based on such a "local realistic theory" versus the predictions of Q(F)T, and we all know the answer. Q(F)T is correct, and local realistic theories are wrong.

In the scientific community that's settled, and now this result can be used to develop new technology. It's now a business of engineers. Though triggered by philosophical prejudices this success is entirely based on making these vague ideas a clear scientific concept based on empirical facts.

In this sense the "philosophical gibberish" lead indeed to a great scientific success, but only after the philosophy has been transformed by Bell to a clear empirically testable prediction, which lead the experimentalist to develop the corresponding technology to realize these empirical tests in their labs.

Today we are in an analogous dilemma with the (scientific!) problem of finding a quantum theory of the gravitational interaction. All attempts are based on purely theoretical speculations without any empirical foundation. For me it's no surprise that there's no success in finding a satisfactory quantum-gravitation theory. It's because there are no empirical hints at what possible quantum effects might be.