Monday, February 10, 2020

Rovelli rejects Eternalism

Physicist Carlo Rovelli just wrote an essay on the philosophy of time, favoring Neither Presentism nor Eternalism. He relies heavily on "Einstein’s conventional definition of simultaneity", without mentioning that the notion is entirely due to Poincare, years before Einstein.

Shortly after the formulation of special relativity, Einstein's former math professor Minkowski found an elegant reformulation of special relativity in terms of the four dimensional geometry that we call today Minkowski space. Einstein at first rejected the idea. (`A pointless mathematical complication'.) But he soon changed his mind and embraced it full heart, making it the starting point of general relativity, where Minkowski space is understood as the local approximation to a four-dimensional, pseudo-Riemannian manifold, representing physical spacetime.

The mathematics of Minkowski and general relativity suggested an alternative to Presentism: the entire four-dimensional spacetime is `equally real now', and becoming is illusory. This I call here Eternalism.
This is cleverly written to convince you that Minkowski derived a 4D geometry version of relativity from Einstein's work. This is not true.

Poincare was the first to formulate a 4D geometry version of relativity, and that paper was written before Einstein published anything on the subject. Minkowski's 4D space was developed directly from Poincare's work, not Einstein. Minkowski does cite Einstein's paper, but does not use anything from it, and it is not clear that Einstein had any influence on Minkowski at all. From Poincare's paper, Minkowski gets the 4D formalism, the pseudo-Riemannian metric, the 4D Lorentz transformations, and the 4D covariance of Maxwell's equations.
This subtle mistake of McTaggart is the same mistake as that which lies at the root of Eternalism. The ensemble of the events of the world is four-dimensional, and we can embrace it within a single image. But this is not a denial of becoming, no more than a single chart of the British royal dynasties is a denial of the fact that events happened in England along the centuries.
Rovelli is right that believing in relativity and using Minkowski does not a belief that all times exist at once. Some people seem to believe that relativity requires determination and a denial of the present. One can still have different philosophical views of time.


  1. To be accurate, a Minkowski space is not 'A pointless mathematical complication', it is an INACCURATE pointless mathematical complication.

    First of all, if you are going to use math to describe reality, you will require sequential time. No time? Then No numbers, or measurements, or ratios, constructions, or calculations are possible either. No exceptions. You want to impress me with your laborious needlessly complex mathematical process, first there had better be a possible process, since without time you literally have nothing you can demonstrate or argue. Since an argument is being made for Minkowski space (however badly flawed), it must be logically concluded there is obviously sequential time in order to construct such a model, thus the entire conjecture of 'equally real now' is proven to be wildly INACCURATE.... in addition since you are here reading this... which requires time to do so and consider as well, it is also self evident.

    1. CFT,

      I think you are right regarding the nature of time. I think you had made this point earlier too, in some comments at this blog (though I don't recall when).

      This is your argument, I think:

      Numbers stand for certain mathematical (mentally conducted) operations that are conceptualized as distinct mental units. (Each mathematical object ultimately stands for an operation.) In other words, any number is the end-product of certain (completed) mental processing. A completed process has a distinct beginning and an end. Hence, a de-finite time has to elapse before numbers can be grasped or their concepts formed (or used).

      If so, your argument is valid.

      BTW, I think this is not the first time you used the phrase "sequential time". Do you mean the "sequential" part just for emphasizing an essential feature of time, or do you have some non-sequential kind of an idea for time, too? If so, any example of its occurrence?


  2. Ajit R. Jadhav,

    My reasoning for sequential time is this:
    If time does not flow in one direction in sequence then numbers and logic are actually meaningless and not possible, since there can be NO CAUSALITY. You can not even read this sentence from left to right if time does not move in one direction. You simply can't n+1 if your order of operations can skip about or go backwards etc. You can not observe action and reaction to understand any kind of process (mathematical or otherwise) unless time goes in one direction sequentially, if it were to skip forward and backward at various rates (i.e. 1, 4, 237, -3, 10x100^23) what exactly would be a rate of anything changing? How can you even construct the necessary logic underlying a number (a precise location in relation to zero on a number line) if you do not have consecutive sequential steps you can progress in? Sequence in calculation is extremely important, which is why all computation requires it, from an abacus, to a CPU, to the neurons firing in your brain.

    Mathematicians and scientists frequently play a silly game where they pretend they are capable of being perched outside of the space and time of the universe itself looking in at it like a dispassionate scientist at a petri dish under a microscope. What they always leave out of their silly arguments is that for them to even pretend such a relative perspective outside the universe itself, they would still have to have their own sequential meta-time in which to ponder their ridiculous deep thoughts. For a perfect fictional example, think of Doctor Who in his preposterous blue phone booth traveling back and forward in time. Every occasion he makes such a ludicrous time trip, he would have to be entirely independent of time, but yet somehow still having sequential time of his own, else how would he even be able to remember his own adventures or avoid death from being aged or de-aged into dust or goo? I won't even get into the lunacy of being able to observe the universe as you travel back in forth in time, pray tell how does one even tell where in time one is if you step outside the universe itself?