theory of the electoweak interaction (i.e. the effective quantum field theory that is found to be empirically valid, as well as theoretically adequate, above the 246 GeV unificaton energy) is underspecified by the theory of quantum electrodynamics. — Pierre-Normand

In plainer words, the theory of the electoweak interaction gives the correct results for experimental data at 246 GeV unificaton energy whereas quantum electrodynamics does not.

Is there anything you would disagree with here?

Wouldn't it be more accurate to say all theories (QED included) would have been consistent with experimental results at the lower energy scale — Frederick KOH

No. That wouldn't make sense. QED is not part of its own set of higher-energy (and shorter-range structure) possible realization bases.

No. That wouldn't make sense. QED is not part of its own set of higher-energy (and shorter-range structure) possible realization bases. — Pierre-Normand

Since it is an empirical theory, what experimental data is it consistent with?

Is there anything you would disagree with here? — Frederick KOH

No but it's not a paraphrase of what I wrote. It ignores the point about underdetermination.

Since it is an empirical theory, what experimental data is it consistent with? — Frederick KOH

You can read Feyman's popular "QED" book, if you're curious; or Google the Wikipedia page, maybe.

You can read Feyman's popular "QED" book, if you're curious; or Google the Wikipedia page, maybe. — Pierre-Normand

So there is empirical data that QED consistent with.

Electroweak theory is also consistent with the same empirical data.

Is there anything you disagree with here?

If for a theory to be fundamental means that it is universal and applies everywhere, at any time, and on every energy/spatial scale, then very few theories are fundamental (not even general relativity). — Pierre-Normand

None of the theories I mentioned seeks to protect itself from falsification by the adoption of any ad-hoc restrictions on where and when they might apply. So, IF that is your definition of fundamental, they all still qualify.

If it means that they provide autonomous explanations that abstract away from features of the contingent material constitution of the entities that they regulate, then stating that they are fundamental doesn't entail anything more than stating that they are autonomous. — Pierre-Normand

It means that the abstractions with which the theories deal, are real. If you are not ready to take that plunge, then "autonomous" may be sufficient to annoy reductionists.

Reductionism requires the behaviour of high level physical systems to always consist of nothing more than the behaviour of its low-level constituents, with most of the details ignored, or as you say "abstracted away", for convenience.

The trouble is, even in physics, reductionism doesn't always work, and we require autonomous higher-level explanations that are irreducible - e.g. The 2nd Law of Thermodynamics.

Quantum mechanics is more of a framework than it is a theory. It consists in a set of formal features shared by more determinate empirical theories such as quantum electrodynamics. Such theories are likewise autonomous. — Pierre-Normand

Whatever you prefer to call Quantum Mechanics does not change the constraints imposed on it and any future theory by Computational Universality.

It could very well be, that high-level theories, taken together, imply the low-level theories, that would otherwise appear fine-tuned.

I found this worth exploring further:

All the alternative theories that would have been consistent with the validity of QED at the lower energy scale — Pierre-Normand

I made this remark in a later comment that I hope you don't disagree with:

So there is empirical data that QED consistent with.
Electroweak theory is also consistent with the same empirical data. — Frederick KOH

But you disagree with this remark of mine:

Wouldn't it be more accurate to say all theories (QED included) would have been consistent with experimental results at the lower energy scale — Frederick KOH

Saying:

No. That wouldn't make sense. QED is not part of its own set of higher-energy (and shorter-range structure) possible realization bases. — Pierre-Normand

Why? Some of that data was in existence before QED was even close to being a mature theory.

Why? Some of that data was in existence before QED was even close to being a mature theory. — Frederick KOH

The set of theories that I mentioned are singled out as being part of the relevant equivalence class. It was meant as a definition of this equivalence class. You quoted only the first part of the sentence where I explain this and then suggested: "Wouldn't it be more accurate to say all theories (QED included) would have been consistent with experimental results at the lower energy scale". But that's not more accurate. That's saying something else entirely, quite irrelevant to what I meant. I had assumed you meant that I had forgotten to include QED in the relevant equivalence class. It need not be included at all, although, trivially, of course QED also is consistent with the experimental results that it itself has been devised to explain. It looks like, through reading only one half of a sentence of mine, and rushing to respond to it, you misconstrued what it meant.

It was meant as a definition of this equivalence class. — Pierre-Normand

So this is the criteria for being in the same equivalence class as QED:

All the alternative theories that would have been consistent with the validity of QED at the lower energy scale — Pierre-Normand

This is not more accurate, but characterizes what valid empirical theories should do:

all theories (QED included) would have been consistent with experimental results at the lower energy scale — Frederick KOH

Is there anything you disagree with here?

So this is the criteria for being in the same equivalence class as QED: — Frederick KOH

No, QED is not part of the relevant equivalence class. You are still badly misconstruing what I said. Are you really incapable of reading a whole sentence? Can't you at least try to make sense of it with reference to the surrounding context of the discussion? Here is the whole sentence, together with the sentence immediately before it:

(PN:) "The theory of the electoweak interaction (i.e. the effective quantum field theory that is found to be empirically valid, as well as theoretically adequate, above the 246 GeV unificaton energy) is underspecified by the theory of quantum electrodynamics. All the alternative theories that would have been consistent with the validity of QED at the lower energy scale (i.e., any energy below 246 GeV) belong to an equivalence class of theories, such that QED can be derived from any one of them."

The alternatives that are being considered are alternatives to the theory of the electroweak interaction; not alternatives to QED itself! It is a class of possible realization bases (analogous to material realization in classical physics or other "high-level" natural sciences) of QED that Karen Crowther meant to specify. If this may help, as an analogy: if you were to define as belonging to the same equivalence class all the hats that fit on your head, then you yourself wouldn't be a member of this equivalence class. You should probably go back and read again the whole post rather than pulling out sentence fragments out of it, because the inferences you are drawing from those fragments are nonsensical, and lead you to miss the point by a mile.

You are still badly misconstruing what I said. — Pierre-Normand

Yes. Because what you say is a bit unexpected.

You define an equivalence class in terms of an existing theory.

You do not define it in terms of a set of empirical data to explain

Have I interpreted you correctly?

Yes. Because what you say is a bit unexpected.

You define an equivalence class in terms of an existing theory.

You do not define it in terms of a set of empirical data to explain

Have I interpreted you correctly? — Frederick KOH

I'm not sure what the difficulty is. There are parameters of the electroweak theory (EWT, for short) that can only be determined empirically through performing experiments in large particle accelerators (through producing and analyzing interactions that involve energies above 246 GeV). If this were not the case, then EWT would not be underdetermined by the experimental evidence that supports QED, and that is available through observing common lower energy interactions outside of particle accelerators. So, if EWT is considered to be one possible "reduction base" of QED (i.e. one that is actual, and not merely possible), then other similar theories that would have alternate values to the empirically determined (at high energy) parameters of EWT would constitute other possible reduction bases of QED. In other words -- and this is the main point -- the actual values of those determinate parameters of EWT are irrelevant to the explanation of the structure of QED, or to the determination of its specific laws.

By the way, I just found out that Karen Crowther recently published a book: Effective Spacetime: Understanding Emergence in Effective Field Theory and Quantum Gravity

Let's get one thing straight first. While EWT is a theory for energies above 246 GeV, it is also for energies below that. In other words it is not illogical to say that it is an alternative theory to QED at energies below that.

Do you disagree?

In other words -- and this is the main point -- the actual values of those determinate parameters of EWT are irrelevant to the explanation of the structure of QED, or to the determination of its specific laws. — Pierre-Normand

In every theory there are open problems describable in terms of the theory itself. Does this apply to what you call autonomous theories?

Let's get one thing straight first. While EWT is a theory for energies above 246 GeV, it is also for energies below that. In other words it is not illogical to say that it is an alternative theory to QED at energies below that.

Do you disagree? — Frederick KOH

It's rather misleading to call it an alternative to QED when QED can be logically derived from it. It would be better to say that it's a more determinate theory. It is inferentially stronger and hence more falsifiable. (It defines a wider "exluded zone", John Haugeland would say; some potential experimental results that it rules out aren't ruled out by QED).

In every theory there are open problems describable in terms of the theory itself. Does this apply to what you call autonomous theories? — Frederick KOH

I can't say. Your first sentence is too vague. Maybe you could phrase it more precisely and explain the relevance of your question to what we've been discussing.

Your first sentence is too vague. — Pierre-Normand

Example "why is the photon massless" is question expressible in terms of QED

Example "why is the photon massless" is question expressible in terms of QED. — Frederick KOH

Yes, sure. The photon's being massless is a requirement for QED being renormalisable. (I didn't remember that, by the way. I Googled it). What's your point?

It would be better to say that it's a more determinate theory. It is inferentially stronger and hence more falsifiable. — Pierre-Normand

So there is a directionality between the two, leaving aside what to conclude from this directionality.

So there is a directionality between the two, leaving aside what to conclude from this directionality. — Frederick KOH

Yes, there is.

What's your point? — Pierre-Normand

Do you consider chemistry autonomous from the theories in quantum mechanics?

Do you consider chemistry autonomous from the theories in quantum mechanics? — Frederick KOH

This binary question is much too crude. There are specific laws of chemistry that are autonomous with respect to the laws that govern simple molecular interactions. The situation here is much more complex and disorderly than it is in the case of the relation between to neighboring effective field theories that merely differ with regard to the energy scales of their respective domains of application. I made mention of a specific example concerning networks of chemical reactions a couple of days ago, though I didn't dig up the reference. Refer to Earley's discussion of "concentration robustness" in chemical reaction networks that satisfy the conditions of the theorem proven by Shinar and Feinberg (Structural sources of robustness in biochemical reaction networks, Science (2010) Mar 12). That's in Earley, Joseph E. Three Concepts of Chemical Closure and their Epistemological Significance.

The main point is that autonomy of a scientific discipline with respect to another always is autonomy in some specific respects. Some laws of chemistry are emergent, some aren't.

This binary question is much too crude. There are specific laws of chemistry that are autonomous with respect to the laws that govern simple molecular interactions. — Pierre-Normand

Then I am not sure how to use your terminology here. What are what you call "high level structures" then? Are they logically different for each specific law even it they refer to the same sort of objects?

Then I am not sure how to use your terminology here. What are what you call "high level structures" then? Are they logically different for each specific law even it they refer to the same sort of objects? — Frederick KOH

I don't recall using the phrase "high level structures" (though that might aptly characterize the objects and properties directly being governed by the laws of a high-level theory). I once mentioned high-level structural features, which include such things as the boundary conditions of a system, and which can serve as a theoretical basis for the direct derivation of the emergent (irreducible) laws of a high-level theory. Those high level structural features thus constitute the specific conditions under which the phenomena being explained and governed by the high-level theory can arise. They are being pointed at by the multitudinous "arrows of explanation" that mess up Weinberg's "grand reductionism" of explanatory-arrow-convergence.

But surely you recognize that the situation in chemistry is very different. There is no specific law of chemistry with the reach and scope of QED. How do you even stay within a single law when talking about a non-trivial experiment.

There is a also a level of porosity between "laws" not found in theories in physics.

For example (from Wikipedia)

"An acid is a molecule or ion capable of donating a hydron (proton or hydrogen ion H+), or, alternatively, capable of forming a covalent bond with an electron pair (a Lewis acid)"

In terms of what law is the statement above made?

But surely you recognize that the situation in chemistry is very different. There is no specific law of chemistry with the reach and scope of QED. — Frederick KOH

Yes, and so? QED may have a wide range of applications and a large domain of validity. This has nothing to do with the question whether or not it might be reducible to some other, more "fundamental", theory.

How do you even stay within a single law when talking about a non-trivial experiment.

How did I "stay within" a single law (whatever that means)? I'm providing counterexamples to Weinberg's imprudent generalization one at a time.

This binary question is much too crude. There are specific laws of chemistry that are autonomous with respect to the laws that govern simple molecular interactions. — Pierre-Normand

Actually, you can't reduce chemistry to quantum mechanics. Chemistry is highly dependent on the history of the universe and the particular values of certain physical constants. Chemistry may also require additional laws like the 2nd Law of Thermodynamics.

So, chemistry may be reduced to Quantum mechanics (specifically the Standard Model) plus initial conditions of the universe, plus several arbitrary constants, plus General Relativity (in order to provide the conditions for atom formation), plus thermodynamics, at least. Not much of a reduction!