Hi Erwin and Christopher,

your essay is very well written and I like the way you approach the topic. It reminds me of Heisenberg's notion of 'closed theories', where he (in contrast to Kuhn) does not see the concepts of different closed theories as incommensurable, but that the new closed theories contain the older ones as limits. Heisenberg's defines a closed theory similar to your claim 1. He describes a closed theory as "perfectly accurate within its domain" and "correct for all time." (Citation from http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.485.9188&rep=rep1&type=pdf). And continues, that a closed theory exhibit such a tight interconnectedness that not a single concept can be changed without destroying the whole system.

Here some remarks I have on your essay, with wich a basically agree:

I do not understand your remark 1 on page 2 of your essay, why the building-blocks of matter should not be considered as fundamental. By the way in my essay I show that in any realistic theory there are conventional elements.

For me unitarity must hold in order I make physical concepts well defined or measurable. It that sense it is a condition, that any empirical theory must fulfil.

Causality: yes, but what causality means is a bit modified in quantum mechanics. In my essay I try to show, that measurable physical quantities are only defined within a measurement context. But because of delayed choice experiments, the context can be set relatively late in the course of a time evolution of the system. This does not change the past state of the system as physical influence but changes, what can be considered as the causal past of a particle. For example in the beam splitter experiment a photon goes through a beam splitter A and is reflected in two mirrors in B and C. And then in D depending, on the settings, one measures either 1) the path (the photon took the path B or C) or 2) the photon went both ways as a superposition. So the casual past (whether 1 or 2 happened) is only given, after the settings in D have been fixed. The weird thing in quantum mechanics is, that the settings can be fixed after the photon has past the beam splitter A.

Finally Lorenz invariance: Lorenz invariance in terms of my essay is a necessary condition my essay to make the defining concepts of the Standard Model like mass and spin definable. But Lorenz invariance only holds if the environment (or the rest of the universe) is more or less homogenous, which is more or less the case in its current state. However if the environment changes I suppose, the fundamental concepts change which might lead to a new closed theory - different than the Standard Model. I'm not sure, whether it is possible to define unified theory, where different possible environments could be subsumed in this theory. The reason for that, is that physical concepts, can only be defined within a closed subsystem, which is separated from the rest of the universe and where the time evolution can be described by a unitary evolution.

Sorry for the maybe to long comment. Hope you find the time to read and comment on my essay.

Luca

    Dear Erwin Handoko Tanin and Christopher Hendriks , Your deep reasoning needs a deep mind. However, the fundamental must be simple and understandable; it must save our thinking, taking into account the limitations of the human resource. New Cartesian Physics, which I discovered, argues that the cause of quantum phenomena in the existence of the pressure of the universe, which overcomes the space, to begin fluctuations. The physical space, which according to Descartes is matter, serves as the foundation for the birth of life. Look at my essay, FQXi Fundamental in New Cartesian Physics by Dizhechko Boris Semyonovich Where I showed how radically the physics can change if it follows this principle. Evaluate and leave your comment there. I highly value your essay; however, I'll give you a rating as the bearer of Descartes' idea. Do not allow New Cartesian Physics go away into nothingness, which wants to be the theory of everything OO.

    "Things that are regarded as fundamental are largely a matter of personal taste. This calls for an objective and reliable notion of fundamentality". Not exactly. When we are working at the same level of description, then the choice of what is fundamental and what is derived is partially arbitrary. This is the reason why we have different formulations of mechanics or of thermodynamics, with each formulation relying on a different set of postulates. There is no subjectivity, just a kind of equivalence among the formal systems that correspond to the same level of description. When we are working at two different levels of description, the postulates of the more fundamental level cannot be derived from the upper level. Again there is no subjectivity.

    I do not see any reason to restrict the meaning of fundamental to postulates only. I can apply the term to whole theories or even to physical objects.

    The Lagrangian of the Standard Model would not be taken as a postulate. First because the generator of time symmetries in quantum mechanics is the Hamiltonian, not the Lagrangian, and it is the Hamiltonian which enter in the S-matrix; second because the Lagrangian of the Standard Model does not describe real particles, but only fictitious bare particles. This Lagrangian depends on unphysical parameters as e_B and m_B. It is only after an ad hoc procedure of renormalization, that the unphysical Lagrangian of the model is replaced by another Lagrangian is function of physical parameters e and m, which are associated to real charges and masses. Check section 11.1 in volume ! of Weinberg book on QFT.

    "Evolution operators must be unitary". This is not true, and we have plenty of examples of non-unitary evolutions: the equation of motion for a molecule immersed in a heat bath, the equation of motion for a unstable particle are two common examples of non-unitary evolutions.

    "Causality: future cannot affect past". Not exactly true. In a non-unitary evolution future cannot affect past because the future is not still given, but in unitary evolutions future is unambiguously defined and required by the past. I can integrate the unitary equations of motion both forward and backward in time without violating causality. In fact both solutions, forward and backward, are needed to formulate a general and consistent theory of electrodynamics. As is well-known the advanced potentials have to be used to cure the unphysical character of the Maxwellian theory, which only uses the retarded potentials.

    "Lorentz Invariance". This is an approximated invariance valid only in the one-particle limit. As is well-known adding a second particle to the system breaks the Lorentz invariance. There is no Lorentz invariant Lagrangian that fully describes a N-particle system, for instance.

    Dear Erwin Handoko Tanin and Christopher Hendriks,

    Thank you for your interesting essay, I appreciated the idea to propose a practical (and relative) notion of fundamentality, it's useful and leaves room for the different analysis of the idea of fundamental through different perspectives and disciplines. My definition, for example, is more philosophical.

    Your proposal moreover, that

    > The fundamentality of a postulate is inversely proportional to the stability of the theory under small deformations in the postulate.

    Is a good one, in my opinion.

    All the best!

    Francesco D'Isa

      Dear Erwin and Christopher,

      Einstein was right when he did not agree with the EPR experiment conclusions and had said, "spooky action at a distance" cannot occur and that, "God does not play dice". Please read Linear Polarization http://vixra.org/pdf/1303.0174v5.pdf

      I look forward to your reply.

      Kamal Rajpal

      4 days later

      Hi Erwin and Christopher,

      Nice discussion of fundamental..."Although there have been many robust and general definitions of the word "fundamental", most cannot be directly applied to scientific concepts. By limiting our scope to postulates, by which we mean mathematical representations of physical laws, and defining fundamentality in terms of a postulate's behavior under deformation, we demonstrate a tentative framework for a practical notion of fundamentality." Best wishes

      I hope you will not mind that I am not following main stream physics...

      By the way...Here in my essay energy to mass conversion is proposed................ yours is very nice essay best wishes .... I highly appreciate hope your essay ....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

      Flavio and Chiara,

      We have read your essay. Thanks for the interesting read. In general, you did a nice job of putting into words ideas that are likely at the back of most people's minds but are difficult to convey. In particular, we value the point you made about the fundamental laws that we consider as most fundamental at a time being manifestations of our philosophical prejudices. These prejudices are extremely hard to recognize (let alone alter) as it is likely that by this point they have become hardwired in our brains.

      As you mentioned, our ideas are indeed closely related. Where they differ is in their approaches to the problem of fundamentality: yours more closely follows the well-treaded philosophical route, while ours -- likely influenced by our scientific background -- represent a first step in attempting to address the issue from a scientifically practical point of view. We briefly touch upon this in our essay: although many excellent and interesting philosophical treatises on the problem of fundamentality in science has been produced, none of them (as far as we know) are of much practical use to a scientist. This is the main driving force behind our work, and what we believe makes it stand out from the many otherwise excellent essays featured here.

      Erwin and Christopher

      Wayne Lundberg,

      In case you missed it, FQXi is looking for essays exploring the meaning of fundamentality, not on which and what object(s) we regard as fundamental:

      https://fqxi.org/community/essay/rules

      "This contest does not ask for new proposals about what some "fundamental" constituents of the universe are. Rather, it addresses what "fundamental" means, and invites interesting and compelling explorations, from detailed worked examples through thoughtful rumination, of the different levels at which nature can be described, and the relations between them."

      Erwin and Christopher

      Luca,

      Many thanks for bringing to our attention Heisenberg's idea; we were not aware of that.

      As for our footnote, please keep in mind that we are approaching the issue of fundamentality from the point of view of a scientist mostly interested in a practical notion of "fundamental". What we were trying to say is that what we regard as the building blocks of matter are often just a convenient choice that makes it easier for us to calculate things. An example is the fact that dualities in string theory allow us to switch between different but equally good descriptions of nature; when we do that, components can turn into composites and vice versa, suggesting that fundamentality is a matter of choice of description. We don't have a very strong opinion on this. It is just an informal reason for limiting our scope to only postulates.

      For your more technical remarks, we will need to explore your essay further before responding to them.

      Erwin and Christopher

      Thank you for the kind words, Francesco D'Isa.

      All the best,

      Erwin and Christopher

      5 days later

      Dear Erwin

      If you are looking for another essay to read and rate in the final days of the contest, will you consider mine please? I read all essays from those who comment on my page, and if I cant rate an essay highly, then I don't rate them at all. Infact I haven't issued a rating lower that ten. So you have nothing to lose by having me read your essay, and everything to gain.

      Beyond my essay's introduction, I place a microscope on the subjects of universal complexity and natural forces. I do so within context that clock operation is driven by Quantum Mechanical forces (atomic and photonic), while clocks also serve measure of General Relativity's effects (spacetime, time dilation). In this respect clocks can be said to possess a split personality, giving them the distinction that they are simultaneously a study in QM, while GR is a study of clocks. The situation stands whereby we have two fundamental theories of the world, but just one world. And we have a singular device which serves study of both those fundamental theories. Two fundamental theories, but one device? Please join me and my essay in questioning this circumstance?

      My essay goes on to identify natural forces in their universal roles, how they motivate the building of and maintaining complex universal structures and processes. When we look at how star fusion processes sit within a "narrow range of sensitivity" that stars are neither led to explode nor collapse under gravity. We think how lucky we are that the universe is just so. We can also count our lucky stars that the fusion process that marks the birth of a star, also leads to an eruption of photons from its surface. And again, how lucky we are! for if they didn't then gas accumulation wouldn't be halted and the star would again be led to collapse.

      Could a natural organisation principle have been responsible for fine tuning universal systems? Faced with how lucky we appear to have been, shouldn't we consider this possibility?

      For our luck surely didnt run out there, for these photons stream down on earth, liquifying oceans which drive geochemical processes that we "life" are reliant upon. The Earth is made up of elements that possess the chemical potentials that life is entirely dependent upon. Those chemical potentials are not expressed in the absence of water solvency. So again, how amazingly fortunate we are that these chemical potentials exist in the first instance, and additionally within an environment of abundant water solvency such as Earth, able to express these potentials.

      My essay is attempt of something audacious. It questions the fundamental nature of the interaction between space and matter Guv = Tuv, and hypothesizes the equality between space curvature and atomic forces is due to common process. Space gives up a potential in exchange for atomic forces in a conversion process, which drives atomic activity. And furthermore, that Baryons only exist because this energy potential of space exists and is available for exploitation. Baryon characteristics and behaviours, complexity of structure and process might then be explained in terms of being evolved and optimised for this purpose and existence. Removing need for so many layers of extraordinary luck to eventuate our own existence. It attempts an interpretation of the above mentioned stellar processes within these terms, but also extends much further. It shines a light on molecular structure that binds matter together, as potentially being an evolved agency that enhances rigidity and therefor persistence of universal system. We then turn a questioning mind towards Earths unlikely geochemical processes, (for which we living things owe so much) and look at its central theme and propensity for molecular rock forming processes. The existence of chemical potentials and their diverse range of molecular bond formation activities? The abundance of water solvent on Earth, for which many geochemical rock forming processes could not be expressed without? The question of a watery Earth? is then implicated as being part of an evolved system that arose for purpose and reason, alongside the same reason and purpose that molecular bonds and chemistry processes arose.

      By identifying atomic forces as having their origin in space, we have identified how they perpetually act, and deliver work products. Forces drive clocks and clock activity is shown by GR to dilate. My essay details the principle of force dilation and applies it to a universal mystery. My essay raises the possibility, that nature in possession of a natural energy potential, will spontaneously generate a circumstance of Darwinian emergence. It did so on Earth, and perhaps it did so within a wider scope. We learnt how biology generates intricate structure and complexity, and now we learn how it might explain for intricate structure and complexity within universal physical systems.

      To steal a phrase from my essay "A world product of evolved optimization".

      Best of luck for the conclusion of the contest

      Kind regards

      Steven Andresen

      Darwinian Universal Fundamental Origin

      Dear Erwin H. Tanin and Christopher Hendriks,

      I have read your Essay wherein you briefly mention the EPR paradox. Einstein was right when he did not agree with the EPR experiment conclusions and had said, "spooky action at a distance" cannot occur and that, "God does not play dice". Please read Linear Polarization http://vixra.org/pdf/1303.0174v5.pdf

      QM claims that an electron can be both spin-up and spin-down at the same time. In my conceptual physics Essay on Electron Spin, I have proved that this is not true. Please read: https://fqxi.org/community/forum/topic/3145

      Kamal Rajpal