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Vesselin Petkov: on 5/16/20 at 23:49pm UTC, wrote Dear Edwin, I see... If by chance you decide to entertain the possibility...

Jenny Wagner: on 5/16/20 at 21:29pm UTC, wrote Dear Dr. Petkov, dear Dr. Crecraft, I have followed your very interesting...

Edwin Klingman: on 5/16/20 at 18:42pm UTC, wrote Dear Vesselin, There is already “exclusion of research directions”;...

Lachlan Cresswell: on 5/16/20 at 9:21am UTC, wrote Dear Vesselin, An interesting essay, that I am at odds with. You comment:...

Vesselin Petkov: on 5/16/20 at 4:45am UTC, wrote Dear Marts, Thank you for your comments. I guess you may also wonder what...

Marts Liena: on 5/15/20 at 11:24am UTC, wrote Dear Vesselin, A most interesting essay, as I was not aware of the...

sherman jenkins: on 5/15/20 at 3:48am UTC, wrote A new era dawns.  Old questions become quaint and historical.  Is the...

Vesselin Petkov: on 5/2/20 at 3:29am UTC, wrote Dear Harrison, Thank you for taking the time to write on this. I found...


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CATEGORY: Undecidability, Uncomputability, and Unpredictability Essay Contest (2019-2020) [back]
TOPIC: Minkowski spacetime - a no-go for objective becoming by Vesselin Petkov [refresh]
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Author Vesselin Petkov wrote on Apr. 15, 2020 @ 13:13 GMT
Essay Abstract

Despite that Minkowski's rigorous arguments for the reality of spacetime impose fundamental limits on our views of the physical world, many papers and books, which deal with the issue of the nature of what exists, completely ignore them as if they did not exist. I am not alone to think that ignoring (and therefore contradicting) such a strict no-go (based on the experimental evidence) is not how science works. That is why, as a case study of this worrying trend, I will discuss Carlo Rovelli's paper "Neither Presentism nor Eternalism" in which he argues that becoming is an objective feature of the world and which is the most recent example of this trend.

Author Bio

One of the founders and current director of the Minkowski Institute. PhD in Physics (Montreal, 1997). PhD in Philosophy of Science (Sofia, 1988).

Download Essay PDF File

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Eckard Blumschein wrote on Apr. 16, 2020 @ 06:25 GMT
Sorry Vesselin Petkov,

While I appreciate any critical dealing with Presentism and Ethernalism, I consider your essay one of the worst I read. You might learn from Sabine Hossenfelder to write understandable short sentences.

With sympathy,

Eckard Blumschein

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H.H.J. Luediger wrote on Apr. 16, 2020 @ 09:15 GMT
Dear Vesselin,

although I disagree with any ideas of reified spaces, your reconstruction of Minkowski's derivation of the necessity of 4D-space is the best and clearest I ever read. And (dephysicalised) it even supports my idea that all frames are equivalent in which the phenomena hold good, i.e. in which the relations between objects (before, behind, within, around, through, along, opposite of, etc.pp.) hold good - not the dynamics of objects!



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Author Vesselin Petkov replied on Apr. 17, 2020 @ 04:09 GMT
Dear Heinz,

Thanks for your comments and specifically for "I disagree with any ideas of reified spaces." I've done my best to show why Minkowski did not reify his die Welt (the World, i.e. spacetime). First, mathematicians do not have this habit. Second, Minkowski excitedly announced the new radical views of space and time (the excitation is much more intense in the draft version of his 1908 lecture) - even this demonstrated that Minkowski believed his arguments proved the reality of (the four-dimensional) die Welt; otherwise there would have been no reason for excitation - mathematicians do not get excited by a four-dimensional mathematical space.

But this is, of course, not an argument in the essay. The main point of the essay is that Minkowski's arguments prove the reality because experiments would be impossible if spacetime were not real. In other words, the main point of the essay is that the reality of spacetime is not just assumed (reified), but proved by experiments. Please see my answer to Harrison Crecraft below on whether Minkowski's arguments can be objected by stating that experiment have different interpretations.

Best wishes,


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H.H.J. Luediger replied on Apr. 17, 2020 @ 17:54 GMT
Dear Vesselin,

I'm confused! What means 'real' to a mathematician? Is space-time reality (like an apple), a model of reality, an idea not contradicting certain observations or an object in mathematicians' heaven? And more important, did space-time exist prior to Einstein/Minkowsk and if yes, in which way?



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Author Vesselin Petkov replied on Apr. 17, 2020 @ 21:30 GMT
Dear Heinz,

Regarding "What means 'real' to a mathematician?" I simply wanted to point out the fact that Minkowski saw in the unification of space and time he introduced something more than just another mathematical space. My guess is that if Minkowski had to answer your second question, he would say that his die Welt (spacetime) is a mathematical model of a real four-dimensional world (when people, including myself, say "spacetime is real" we mean precisely that).

[Instead of asking you to see my answer to another comment, I will repeat it here] Let us look again at the two figures in the attached file - they represent two ontologically sharply different entities (of different dimensions): Fig. 1 depicts the suggested by our senses three-dimensional meter stick (and a three-dimensional world), whereas Fig. 2 represents a four-dimensional entity - the stick's worldtube - (and a four-dimensional world). These figures are definitely not merely different equally good descriptions of the physical reality, because reality is either 3D or 4D. If someone rejects the accepted view and holds that the dimensionality of the world is not a fundamental feature of the world (on equal footing with its very existence), then that should be explicitly stated and arguments, based on the experimental evidence, should be provided.

Now the question is whether experiment can determine the dimensionality of the meter stick (and therefore of the world). This is precisely what the experimental verification of length contraction did. And I would like to stress it again: I think that is the strongest form of experimental verification - if the meter stick's worldtube were not a real 4D object (depicted in Fig. 2), length contraction would be impossible.

Best wishes,


attachments: 1_BlockU.jpg

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Cristinel Stoica wrote on Apr. 16, 2020 @ 15:51 GMT
Dear Vesselin,

I enjoyed very much to read your essay! Misconceptions about Minkowski's spacetime and his four-dimensional ontology still exist, and even in places where you'd expect better. Your very well explained essay clarifies such misunderstandings. I'm glad to see it here. Indeed, Minkowski spacetime provides a no-go result against absolute time and space, with similar, if not higher importance as other no-go results like Bell's theorem. I wish you success in this contest!



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Author Vesselin Petkov replied on Apr. 17, 2020 @ 04:11 GMT
Dear Cristi,

Thanks a lot! I guess you are aware that such misconceptions are often caused by inadequate views on the nature of physical theories (e.g. one can hear "theories are just descriptions"). Perhaps, the saddest example of how such inadequate views can prevent even great scientists from making a discovery is Poincaré's failure to discover the spacetime structure of the world. He believed that our physical theories are only convenient descriptions of the world and therefore it is really a matter of convenience and our choice which theory we would use. As T. Damour stressed it, it was

"the sterility of Poincaré's scientific philosophy: complete and utter "conventionality" ... which stopped him from taking seriously, and developing as a physicist, the space-time structure which he was the first to discover."

(Colleagues, interested in the drama of the discovery of spacetime by Minkowski and Poincaré can find more details on, including facts which appear to indicate that Minkowski arrived independently at what Einstein called special relativity and spacetime, but Einstein and Poincaré published first.)



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Harrison Crecraft wrote on Apr. 16, 2020 @ 21:01 GMT
Dear Dr. Petkov,

Your essay clearly accomplishes your goal, arguing that Minkowski spacetime does not allow for objective becoming. However, you seem to accept Minkowski spacetime as settled fact. The only true facts are validated observations. Everything else is interpretation of those observations, based on reasonable and accepted assumptions. But assumptions are not observable, and agreement on reasonable and accepted assumptions, no matter how widespread, is not proof of their truth, as the history of physics has demonstrated time and again.

In my essay, I start with an empirical model of observations as the starting point for physical description. I then consider various assumptions that underlie various conceptual models of physical reality. I conclude that the most reasonable conceptual model, in fact, does accommodate objective becoming, and that the conventional physical interpretation, on which Minkowski spacetime is based, is an idealized special case that does not in fact exist.

I hope you will take a careful read of my essay, consider the validity of the implicit assumptions that underlie conventional physical interpretations, and share your thoughts.



Harrison Crecraft

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Author Vesselin Petkov replied on Apr. 17, 2020 @ 04:14 GMT
Thanks a lot for your comments and particularly for "Everything else is interpretation of those observations" (although I am not sure I understand what you mean by "The only true facts are validated observations").

Regarding your comment "you seem to accept Minkowski spacetime as settled fact", please see my answer to H.H.J. Luediger above on what makes me think so. I suspect you may object that, for example, the experiments which confirmed the relativistic kinematic effects (that I wrote would be impossible if spacetime did not exists) have more than one interpretation.

If you really think so, then you can have a look at the more visualized version of Minkowski's explanation of length contraction (see p. 40 of; the two figures below are from the article - both the theory and the experiment say that the contracted meter stick (Fig. 1) contains three colours, but this is only possibly if the meter stick exists equally at all moments of its history in time (Fig. 2), which proves the reality of spacetime.

I believe this thought experiment clearly demonstrates that length contraction (and more generally relativity of simultaneity, because both length contraction and time dilation are specific manifestations of relativity of simultaneity) have a single interpretation.

Also, I think technology is probably sufficiently advanced to make such an experiment possible. But no one would spend any money on it because it is absolutely certain that any experiment would prove what is depicted on Fig. 1. Unless, a billionaire, interested in science, decides to support such a project....

Best wishes,

Vesselin Petkov

attachments: BlockU.jpg

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Author Vesselin Petkov replied on Apr. 17, 2020 @ 04:18 GMT
I am sorry - the first line somehow did not appear:

Dear Dr. Crecraft,


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Harrison Crecraft replied on Apr. 17, 2020 @ 20:18 GMT
Dear Vesselin,

Thank you for your response and further illustration of Minkowski spacetime. You state in The Ultimate Judge “all three relativistic effects have been repeatedly confirmed by experiment.” I believe to be more accurate, you should say “all three relativistic effects have been repeatedly shown to be consistent with experiment.” I would then agree 100% with you. However, consistency between experimental results and the interpretation of experimental results is not proof of the assumptions underlying the interpretation.

Observer A and observer B do indeed have different inertial frameworks and perceptions of time. Furthermore, Lorentz transformations can transform one reference to another with no loss of information. This is fact. Minkowski spacetime, however, is based on the assumption that physical reality is independent of any particular inertial reference frame, i.e. that physical reality is non-contextual. Certainly, non-contextuality is consistent with relativity experiments, but again, consistency is not proof.

Non-contextuality is more difficult to reconcile with quantum experiments, yet most physicists cling to the idea of a non-contextual quantum reality. This difficulty is manifested by the lack of any accepted quantum interpretation. In my essay, I argue that a contextual interpretation is consistent with quantum and relativistic experiments, but it is more general, it is based on empirically consistent and conceptually simple assumptions, and it accommodates objective becoming. I hope you will take to time to read it.



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Yehonatan Knoll wrote on Apr. 17, 2020 @ 10:53 GMT
Dear Vesselin,

I couldn't agree more that the Block-Universe view is not taken seriously enough. However, for the BU view to have any physical consequences, one needs to represent those (extended) world-lines in it or, more generally, the energy-momentum tensor on the r.h.s. of Einstein's field equations. And there is a problem, as Einstein himself was well aware (referring to the r.h.s. as "the wing of the palace made of wood"). But in fact, that problem can be traced to the self-force problem of classical electrodynamics, which has never been properly solved.

After years of extensive research I can say with reasonable confidence that the combination of the two - the BU view with a properly represented energy-momentum tensor - solves all the major open problems in physics, from the foundations of QM to the dark-matter mystery .

Moreover, my proposal can supply you with yet another `weapon' against BU deniers: A proper solution to the self-force problem implies that classical electrodynamics cannot be formulated in terms a Cauchy initial value problem. In other words, the (extended) world-lines of particles are defined globally in the BU (albeit constrained by local relations, namely local energy-momentum conservation and Maxwell's equations).

One additional radical consequence is explored in my essay.



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Author Vesselin Petkov replied on Apr. 17, 2020 @ 18:47 GMT
Dear Yehonatan,

Thanks a lot for all this information. I have already created a folder FQXi 2020 on my computer and, like all colleagues here, will have a lot to read and think!

I am glad you are also interested in the self-force. Here is an item from the list of new results in my book Relativity and the Nature of Spacetime:

"The proper description of electromagnetic phenomena in non-inertial reference frames in terms of the anisotropic velocity of light leads to the definition of another overlooked quantity – an anisotropic volume element – which simultaneously solves two problems – it accounts for the factor of 1/2 in Fermi’s potential for a charge in a gravitational field and the 4/3 factor in the self-force acting on a non-inertial charge."

Regarding your results I will definitely have a close look.

Best wishes and good luck,


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Israel Perez wrote on Apr. 17, 2020 @ 17:41 GMT
Dear Vesselin

The topic you deal with is certainly interesting, although I see it somehow disconnected from the main topic of the contest (at least in its present version). Anyway, nice and well argued!

Good luck in the contest!


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Mozibur Rahman Ullah wrote on Apr. 25, 2020 @ 06:31 GMT
Dear Vesselin,

I very much agree with your observation that a conversation about the nature of spacetime is long overdue. I tackle similar territory in my own essay from the perspective of quantum logic, a perspective mind you, when I first heard about it I dismissed as not being logic. I invite you to take a look. I should say though I take a diametrically opposite view to yours and argue for an objective becoming.

I recently came across a paper by a historian of physics who argued that Einstein did not view his theory as a geometrisation but as the unification of gravity and inertia. I found that quite thought provoking.

I wish you all the best with the contest.

Warm wishes

Mozibur Ullah

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Harrison Crecraft wrote on May. 1, 2020 @ 15:55 GMT
Hi Vesselin,

Our previous discussion has prompted me to take a deeper dive into empirical measurements, facts, and interpretations.

The Michelson-Morley experiment demonstrated the truth of statement A: “Whatever inertial reference frame is measured from, the speed of light is the same.” We can take A as empirical fact. A underlies the...

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Author Vesselin Petkov replied on May. 2, 2020 @ 03:29 GMT
Dear Harrison,

Thank you for taking the time to write on this.

I found the discussions on the nature of spacetime to be almost always discouraging, especially when I ask to focus on Minkowski's argument - length contraction - since it allows a single explanation (that does not contradict the experimental evidence) and because of that it is clear cut: if that argument is refuted it amounts to rejecting the reality of spacetime (the same applies to time dilation and the twin paradox, but their analysis is a bit more complicated). Despite that every time I explicitly ask to address this argument, every time it is ignored and other arguments are put forward. Unfortunately, this happened again - I even attached a diagram of a more visualized presentation of Minkowski's argument.

Frankly, I really do not know how to comment; at least, I hope you understand.

Best wishes,


P.S. In physics, the physical world is regarded as independent of reference frames (used for its description; what is described does not depend on the choice of its description). This is not debated in physics. On 2-3 occasions I witnessed almost identical reaction when non-physicists try to question it - "I have no time for exercises in philosophy of language".

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sherman loran jenkins wrote on May. 15, 2020 @ 03:48 GMT
A new era dawns.  Old questions become quaint and historical.  Is the whole community ready?  Or is physical reality too dangerous for our collective understanding at this time? 

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Marts Liena wrote on May. 15, 2020 @ 11:24 GMT
Dear Vesselin,

A most interesting essay, as I was not aware of the thoughts of Minkowski.

I, however, am a presentist who believes time is illusary. I am also a staunch believer in a finite, rotating 3D universe. If you need to attach a time axis then I think I ascribe to typical time (relative, dilated time flow, wrt a defined volume of space) and atypical time (absolute, cosmological, expansion of aether master clock) both running together, to be used cautiously and not confused.

I haven't read Rovelli's paper but he usually strikes a resonance with me, despite our numerous disagreements.

While I struggle to work out and define objective reality, I met a guy in the park today who argues strongly that there is only subjective reality! (I must read 'Zen and the art of motorcycle maintenance' again !)

Regarding Minkowski again, I do not personally buy into length contraction but rather think there is only time flow dilation to deal with (Inertia of energy density)

best wishes,

Marts Liena

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Author Vesselin Petkov replied on May. 16, 2020 @ 04:45 GMT
Dear Marts,

Thank you for your comments. I guess you may also wonder what should be done when there are so many people with so many different views of the same world. For this reason, one of the elements of the research strategy of the Minkowski Institute (Montreal) is to provide justification for excluding research directions. I am well-aware that some people will be outraged by such undemocratic intervention. The first class on my course on foundations and philosophy of spacetime was always devoted to the explanation of some basis principles, e.g., that there is no democracy in science (and I was telling the students that everyone is, of course, entitled to their views, but we should constantly keep in mind that Nature does not care about our personal opinions). I suspect that “political correctness” in science is hampering the advancement of fundamental physics. Personally, I will be genuinely glad if I am shown (with arguments based on the experimental evidence) that a project I am working on or a view I hold are wrong. I am convinced I am not alone since, ultimately, we want to understand the world, not to demonstrate that we are right.

Best wishes,


P.S. With regard to your last paragraph, I hope you are aware that both time dilation and length contractions are specific manifestations of relativity of simultaneity.

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Edwin Eugene Klingman replied on May. 16, 2020 @ 18:42 GMT
Dear Vesselin,

There is already “exclusion of research directions”; such is inherent in entrenched establishments. The members of such establishments are human, hence essentially tribal, and “our tribe is always right.”

I quote McEachern in my essay:

"…Planck observed a century ago, the problem is, theoretical physicists are not part-icularly adept at identifying that some things even are assumptions; with the result that ‘self-evidently true' facts lead to long periods of stagnation, until these "facts" are eventually shown to be just idealistic false assumptions.”

Einstein built his false assumptions into his definition of ‘inertial reference frame’ and Minkowski built his false assumptions into his 4D ontology.

Special relativity is not the only area of physics that has false assumptions in its fundamentals, but all such areas have books, papers, lectures, professorships, and other investments that oppose any serious focus on such fundamental false assumptions. ‘Political correctness’ has nothing to do with it. It’s the nature of the hierarchical establishment, period.

The lack of real progress in 40+ years is near proof of this state of physics, and many in these contests believe the dam may be starting to break, but that’s probably optimistic.

Best wishes,

Edwin Eugene Klingman

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Author Vesselin Petkov replied on May. 16, 2020 @ 23:49 GMT
Dear Edwin,

I see... If by chance you decide to entertain the possibility that both Einstein and Minkowski are correct (which is an experimental fact for all who studied both their works and the overwhelming experimental evidence that confirmed their results), you could look at the visualized version of Minkowski's explanation of length contraction (see the text quoted in my reply to Harrison Crecraft and the figure given there) and I will be glad to answer all your questions.

I am truly amazed that you quoted Planck - the man who first realized the depth of Einstein's special relativity and was instrumental in its fast acceptance. I guess you did not like what Planck sadly wrote (in his "Scientific Autobiography" and in his book "The Philosophy of Physics") about the acceptance of new revolutionary theories:

"This experience gave me also an opportunity to learn a fact - a remarkable one, in my opinion: A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it."

Best wishes and, again, I am willing to reply to your questions,


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Lachlan Cresswell wrote on May. 16, 2020 @ 09:21 GMT
Dear Vesselin,

An interesting essay, that I am at odds with.

You comment: ” …the accepted view that dimensionality of the world is one of its most fundamental features..” Dimensionality, per se, is a human construct that can be most confusing. Your essay discusses 3D universe vs 4D spacetime from the viewpoint of Minkowski. I wonder what we are really discussing when...

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