When do we stop digging? Conditions on a fundamental theory of physics by Karen Crowther

Dear Karen,

I appreciated your essay, an interesting shift in perspective. In a certain sense, it's a way to answer to a question with another question, but in a productive way, congratulations.

You write that "Physics does and must assume that we are able to formulate a physical description of all phenomena, and that this description is useful to us as far it can be". I wonder if the "useful" parameter should change, for questions intrinsically philosophical as "fundamentality" - but as you pointed with your paper, questions and answers often changes together.

All the bets, and thank you for sharing your interesting point of view,

Francesco D'Isa

Dear Karen,

I appreciated your essay, an interesting shift in perspective. In a certain sense, it's a way to answer to a question with another question, but in a productive way, congratulations.

You write that "Physics does and must assume that we are able to formulate a physical description of all phenomena, and that this description is useful to us as far it can be". I wonder if the "useful" parameter should change, for questions intrinsically philosophical as "fundamentality" - but as you pointed with your paper, questions and answers often changes together.

All the bets, and thank you for sharing your interesting point of view,

Francesco D'Isa

Karen--

Very nice essay, well written as well as thoughtful. I do think that some of your criteria for being fundamental are a little overly restrictive, which I think may be related to your focus on QFT and GR as the only theories worthy of attention. I was especially interested in your essay because I wrote an essay with a similar intent, and I am hoping you will take a look at it and offer some feedback. I will not try to elaborate on my observations concerning your criteria at this point because to do so would essentially just rehash what's in my essay, but perhaps we can exchange more thoughts later based on your reaction to the ideas expressed there. Meanwhile, let me just say that I enjoyed reading you essay.

Dear Karen,

congratulation for one of the few essay that deservers to be called an eassy. Quite original and well structured. I rated it very high.

Although you approach the problem from a very different perspective (you might like to have a look at my essay for comparison), I definitely like your clarity and rogour.

As a curiosity, let me mention that I am a frined of Niels Linnemann (who I also quoted in my essay as an example for proposals of emergent gravity), that I think works on similar things of yours, in Geneva. Do you know him?

Good luck, and I wish you the very best,

Flavio

Dear Karen Krowther,

Is the absence of evidence to the contrary really enough or should serious doubts also matter? In mathematics there were many proofs showing the existence of God. I also would likr to remind of G. Cantor's diagonal argument.

Do you accept for instance Klingman's argument on simultaneity as evidence?

Eckard Blumschein

dear Karen Krowther,

This is certainly a good question and I'm glad you have addressed it.

Should your criteria for fundamental not also include some measure of completeness? I mean one can certainly define a self contained mathematical structure or in the case of the Standard Model a theory that eventually explains all experimental results. However does the theory answer all questions of our human condition?

As Edington's Fish Story points out, the most fundamental will eventually be the construction and methodology of out inquiry?

Thank you for writing this essay

Wolfgang Baer

Dear Karen,

Very well done. Interesting idea, nicely framed & constructed. You soundly argued the grounds for digging and presenting the conditions to stop. But don't you think it may just be for a tea break, and we may then be back to work again on infinite time etc?

I was surprised to find the SM classified as 'a Theory'. I don't mean I'm wedded to it but not sure it qualified!) . I was also surprised to find Special Relativity and QM sidelined, but it was interesting, refreshing and educating to consider from that different viewpoint. We do all learn different physics, or learn it differently, after all (and unlike many I don't insist my own worldview is correct!)

Do you think we'll evolve the intellectual capacity to understand a complete TOE? If a computer needs to be the size of the universe to predict it's future might our brains not need to be rather larger to hold the data?

My own essay suggests that with a little more complexity some things get simpler. Two more momenta identified in OAM seem to remove weirdness (meeting one of your requirements if correct) and the bar for unity with SR. I hope you'll read and analyse (alongside Declan Trail's with the maths code.)

I think yours hit all the scoring criteria well so I have it down for a top score. We share a few concepts, neither of us propound some unfalsifiable theory, and I agree your flexible conclusions.

Very nice job.

Peter

Dear Karen;

Throughout your postulates it can be seen that you are assuming as absolutely valid the reductionist approach. From many angles (epistemologically, methodologically -Bell's theorem-, and experimentally -double slit experiment, entanglement experiments, etc.) it has been shown that this approach is not appropriate for any TOE.

I like your list of the conditions a physical theory should comply with in order to be considered fundamental; but you are only applying it to the current paradigms applied by the mains stream physics. Mainstream physics is plagued with ill defined fundamental concepts (space, distance, time, mater, etc.) and lacks epistemological and ontological foundation (it is full of contradictions and paradoxes). As a philosopher surely you are very aware of it.

I invite you to check the critique and proposed solutions I make to these problems in my essay "What is Fundamental". I hope that with your background you would make good contribution to the discussion.

Truly yours;

Diogenes

Dear Karen,

I liked your essay and I think it is a nice idea for this essay contest to make a list for of necessary conditions for a theory to be fundamental. I have some questions and remarks.

I also always thought, that a fundamental theory must be non-perturbative. But I never had a clear justification for that. And in my current essay - very implicitly - I doubt, that a fundamental theory can be non-perturbative for the following reason: fundamental concepts can only be defined in a free theory. This seems to be true for Newtons laws, where the laws are valid only if a system is moving relative to an inertial system. But the definition of the inertial system itself is only possible by postulating the force free laws for it. (This may lead to a conventionalism à la Poincaré.)

Similarly in Quantum field theory, where the fundamental concepts are the free particles, which can only be defined in a free theory. So that the theory of interaction necessarily must be perturbative. Or not?

Another obvious condition for a fundamental theory is: empirical adequacy. Why did you leave this out? To evident? To unproblematic? Or to complicated to discuss?

I think this is not simple. Can a fundamental theory define itself its observable consequences? Or must observational statements be independent of the fundamental theory in order for the for the fundamental to be falsifiable? In my essay I show that in any fundamental theory that has some realistic elements, there are conventional Elements. And that what is an empirical statement and what is a definition is not given by the theory itself.

Best regards,

Luca

Dear Karen,

thank you for your nice reply, I wish you all the best for your essay!

Bests,

Francesco

Dear Karen,

Excellent essay -- a pleasure to read! And you hit the nail right on the head regarding the question "What is fundamental?".

The "Natural (no "fine-tuning" of parameters)" criteria is interesting. Sure, we might desire a fundamental theory to not contain fine-tuned parameters. But what if, by sheer bad luck, the universe happens to contain such parameters -- such a theory might be unsatisfactory but this doesn't seem like a good reason to rule it out?

Best regards,

Paul

Your essay is a reasonable overview of the questions related to quantum gravity. My only disagreement might be with the issue of weirdness. Quantum mechanics, and I mean plain vanilla QM, is in many ways very weird. Quantum gravity is likely to have a lot of very strange features.

I suspect we may never come up with a completely fundamental quantum gravity that is not on some level an EFT. The Planck length is the shortest length that a quantum bit may be identified, at least in principle. We may be able to arrive at a reasonable quantum gravity close to the Planck scale. The reason for this is that quantum gravity may have close identification with the quantum measurement problem.

Quantum measurement ultimately involves a set of quantum states that encode the quantum states of a system. The occurrence of a classical stable state in the outcome of decoherence is something quantum mechanics is not able to compute. It may be that this process is a form of Godel loop or self-referential system of states encoding states. This then leads to the problem in mathematics of propositions that are true but unprovable. For quantum mechanics it might similarly mean there exist states, such as classically stable states and observed measurements, that are true but not provable by quantum mechanical "computers."

The issues with quantum information and black holes may ultimately reflect something similar. I suspect it could be that quantum gravity as a fundamental theory is not derivable or computable in any formal way.

I offer in my essay what I suspect is an effective theory, and in fact make various approximations, that might result in measurable outcomes in gravitational wave experiments. What is fundamental in the end is just what your feet stand on at the lowest level at the time.

Cheers LC

Hi Dr Karen Crowther

Nice observation on present day Physics.... "Ultimately, at any stage we may not be able to tell whether we've reached rock bottom, or even if there is a base level" ... and a checklist is a nice idea... dearDr Karen Crowther

............. very nice idea.... I highly appreciate your essay and hope you may please spend some of the valuable time on Dynamic Universe Model also and give your some of the valuable & esteemed guidance

Some of the Main foundational points of Dynamic Universe Model :

-No Isotropy

-No Homogeneity

-No Space-time continuum

-Non-uniform density of matter, universe is lumpy

-No singularities

-No collisions between bodies

-No blackholes

-No warm holes

-No Bigbang

-No repulsion between distant Galaxies

-Non-empty Universe

-No imaginary or negative time axis

-No imaginary X, Y, Z axes

-No differential and Integral Equations mathematically

-No General Relativity and Model does not reduce to GR on any condition

-No Creation of matter like Bigbang or steady-state models

-No many mini Bigbangs

-No Missing Mass / Dark matter

-No Dark energy

-No Bigbang generated CMB detected

-No Multi-verses

Here:

-Accelerating Expanding universe with 33% Blue shifted Galaxies

-Newton's Gravitation law works everywhere in the same way

-All bodies dynamically moving

-All bodies move in dynamic Equilibrium

-Closed universe model no light or bodies will go away from universe

-Single Universe no baby universes

-Time is linear as observed on earth, moving forward only

-Independent x,y,z coordinate axes and Time axis no interdependencies between axes..

-UGF (Universal Gravitational Force) calculated on every point-mass

-Tensors (Linear) used for giving UNIQUE solutions for each time step

-Uses everyday physics as achievable by engineering

-21000 linear equations are used in an Excel sheet

-Computerized calculations uses 16 decimal digit accuracy

-Data mining and data warehousing techniques are used for data extraction from large amounts of data.

- Many predictions of Dynamic Universe Model came true....Have a look at

http://vaksdynamicuniversemodel.blogspot.in/p/blog-page_15.html

I request you to please have a look at my essay also, and give some of your esteemed criticism for your information........

Dynamic Universe Model says that the energy in the form of electromagnetic radiation passing grazingly near any gravitating mass changes its in frequency and finally will convert into neutrinos (mass). We all know that there is no experiment or quest in this direction. Energy conversion happens from mass to energy with the famous E=mC2, the other side of this conversion was not thought off. This is a new fundamental prediction by Dynamic Universe Model, a foundational quest in the area of Astrophysics and Cosmology.

In accordance with Dynamic Universe Model frequency shift happens on both the sides of spectrum when any electromagnetic radiation passes grazingly near gravitating mass. With this new verification, we will open a new frontier that will unlock a way for formation of the basis for continual Nucleosynthesis (continuous formation of elements) in our Universe. Amount of frequency shift will depend on relative velocity difference. All the papers of author can be downloaded from "http://vaksdynamicuniversemodel.blogspot.in/ "

I request you to please post your reply in my essay also, so that I can get an intimation that you replied

Best

=snp

Hello Karen,

Downloaded your essay, browsing it now, commenting on the passing scenery.

Like your application of concept of inversion to non-fundamentals of mainstream physics. Important attribute of Clifford algebra is that it is invertible. If one is a fan of the geometric interpretation of the Hestenes community, then one would expect the invertibility to be easily visualized. Given that the geometric product of two vectors gives a scalar and a bivector, why is it that the product of a scalar and a bivector gives only a bivector? Can you help me understand that? True that the bivector is comprised of our two original vectors, however two individual vectors are topologically distinct from the bivector.

The second section, where you "...outline some of the different ideas of fundamentality associated with modern physics", gets right to the question of a fundamental length. One can have but one fundamental length in a QFT. Effective field theories have two or more. I think all are agreed that Compton wavelength is best choice. Problem enters with renormalization. One needs a physical model that naturally contains the renormalization coefficients of QED. Requirements seem to be gauge invariance, finiteness, and confinement. Your question at the end of that section "Why are

we currently digging for a more fundamental theory?" appears in large part answerable with a single word - renormalization. Tho of course there is more to it than that.

You open the third section with the assertions that

first, "...the framework is mathematically ill-defined". One might suggest that the geometric interpretation of Clifford algebra simply cannot be ill-defined, as in the present context it is simply the eight component Pauli algebra of interactions of the fundamental geometric objects our physical Euclidian space - one scalar, three vectors, three bivectors, and one trivector. It is not ill-defined. Hestenes' wonderful original text is imo the best reference if you're not into this. 50th anniversary 2nd edition was published a few years ago. Amazing how slowly good ideas propagate sometimes.

secondly, you mention renormalization. Agreed on this. One needs a model that naturally contains the renormalization coefficients. Without that both singularity and boundary seem intractible.

third is the problem of gravity. Again the Hestenes camp has this sorted out to some great degree, and particularly the Cambridge group. Equivalence of their gauge theory gravity and GR was demonstrated in a series of papers back in the 90s. So the possibility exists of a geometric algebra model in flat Minkowski spacetime, using interactions of the Pauli wavefunctions at the Compton wavelength say for instance of the electron and the event horizon of the Planck particle to make a model.

darn. i'm new to posting here, hope i'm not hijacking your thread. Going point by point thru your essay, trying to be relevant. And know someone will kick me in the shins if this is over the top.

point is geometric algebra is a great tool, need to start there if one wants fundamental understanding of how physical objects interact in physical space. Get the geometric structure right. Then throw in the fields and see what happens.

still a ways to go to get thru your essay, but feel like i've gone on too long already. Hope to come back to it.

Dear Karen

Very nice essay and direct to the point, no heavy philosophizing and repeating arguments that has been heard a million times.

I said this in my essay which essentially what you have said

" This structure had to be simple, basic but showed all the present physics in a clear and COHERENT way. That is, what are space, time, mass, charge, spin, interaction and most of all why the electron, the proton and "photons" exist. They should be interrelated aspects of a fundamental system."

My idea takes into account all the requirements that you mention

https://fqxi.org/community/forum/topic/3127

Thank you.