Shortly after the formulation of special relativity, Einstein's former math professor Minkowski found an elegant reformulation of the theory 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 4d, pseudo-Riemannian manifold, representing physical spacetime.Other make this argument that relativity implies a eternalism philosophy of time. I disagree with this argument. You can talk about spacetime with either Galilean or Lorentz transformations. If that is eternalist, then it is either with or without relativity.
The mathematics of Minkowski and general relativity suggested an alternative to Presentism: the entire 4d spacetime is `equally real now', and becoming is illusory. This I call here Eternalism.
Note that Rovelli is compelled to make his relativity story all about Einstein, even tho he had nothing to do with the issue at hand. Minkowski did not reformulate Einstein's theory, as it is not clear that Minkowski was ever influenced by anything Einstein wrote. Spacetime relativity was first published by Poincare, and Minkowski cited Poincare.
Rovelli ends up wanting some compromise between presentism and eternalism, as both views are really just philosophical extremes to emphasize particular ways of thinking about time. This might seem obvious, except that there are a lot of physicists who say that relativity requires eternalism.
If you are going to use a model where time is already part of the shape of the graph itself, No, nothing will move, or can move, since it is part of a static imaginary representation of all time, past and present. What you are doing when you skip around inside such a Minkowski space is merely hiding from the fact that you are using an undisclosed/undefined 'pointer' that CAN MOVE spatially/chronologically around inside of your space time model... and this pointer is just a fiction and can't be used to describe any process of possible transition inside the Minkowski space time since it isn't even part of your model at all. Basically, all you are really doing is just offloading all movement into the observer's purely imaginary perspective which exists entirely outside of the fictional constraints of a static graphical representation of time and space. When it takes something that your model itself claims does not exist to allow your model to function, you're in very deep doo-doo.
If you screw around with time frames, also remember there is nothing in the model of time frames which allows causality whatsoever except through arbitrary hand waving (the externally directed arrow of time by the observer of the model) which allows for for you to move from one static frame or point to the next in any manner you choose, to even consider that as some kind of 'movement' or process would require an external meta 'time' with no relation to the model in which some transition could occur.
For those who insist on the delusion of math as 'reality', There is no such thing as math outside of time. This is simply not possible, and is a result of willfully hidden platonic mysticism. All math is a entirely dependent upon logical operational processes connected to rigidly sequential evenly spaced place holders (numbers), none of which can be used, considered, or evaluated without time. You can't even add 1 + 1 without a logical operation which requires at the very least a before and after. If you beg to differ, please provide demonstration of even one single operation that can be performed without time. I'm very curious to see what a logical process without the time to process looks like.
It is strange that so many supposedly clever people would be so fond of a paradigm like Minkowski space time which logically excludes the very possibility of their own mathematical means of evaluating it.
I don't understand the relativity theory, because I never studied it that way. (XII std. exam questions don't count.)
However, if I may so comment:
>> "You can't even add 1 + 1 without a logical operation which requires at the very least a before and after."
What you say is true, for, there must be at least a time lapse between a consciousness grasping that the left hand-side of an equation is equal to the right hand-side.
That is, even if the time-lapse is not allowed in the physical reality, in the sense that some physical change might perhaps occur precisely at the same time that some other physical change occurs. In such a case, the two inter-dependent changes being quantitatively characterized as two sides of an equation.
Can such a thing hold? Well, in the statics in Newtonian mechanics of two balls resting at the bottom of a container, with one ball on top of them. The two reaction forces by the two balls must equal the weight of the gravity being exerted by the ball on the top. In the absence of an external disturbance, the situation continues for all times, and therefore, abstractly, we may say that F_1 + F_2 = F_3, without making a reference to time.
I am sure you were referring to something else, particularly from the relativity theory, in saying what you did.
Just one more word. 1+1 = 2 can also be seen as 2 = 1+1. Quantitatively. Even if the forward process and the backward process do exist, if they take the same time, then in making the equation, it seems, we cancel it out. ... Is this what you had in mind?
Anyway, as I said, I don't understand the relativity theory. So, most of this comment should be irrelevant.
for numbers to exist even abstractly, they must be within a pre-existing framework that allows their progression from one to the next. Once you have the framework, you can count 1, 2, 3, 4, etc. Try explaining what numbers are to a child without any framework of logical progression, it's utterly meaningless. Without that logic of a predetermined progression, you can't have numbers, much less the mathematics that depends upon said numbers. All progressions require sequential time to exist, There are no exceptions.
Minkowski space time treats time as part of an utterly fixed spatial geometry, which makes any such progression (numeric or otherwise) impossible, there is no past, present, or future (ie, no 1,2, or 3) in such a model, it's just a static shape, there is no movement since time has been compressed into the spatial depiction already. People who dither with space time imagery pretend that it explains things because they then move their pointer of perspective around inside the model, all the while not acknowledging that the only thing that allows their model to have any functional resemblance to our universe is through their utterly undefined magical perspective pointer which acts like a meta time film projector for their utterly static frames of space time to play through like some kind of movie. This is bad for multiple reasons, the least of those being that their relative perspective point is not valid at all since it is not even existing within the model universe but is entirely outside of it, and the worst being that the only causality whatsoever in their model is due to the undefined outside magical observer (god perhaps??). The frames of their space time universe have no way of interacting with one another sequentially or otherwise, only the illusion of movement is provided by an outside the model of space time observer moving inexplicable in a forward through time direction. I'd also like to point out, you can't count to ten inside of a space time universe. Since we strangely enough can count higher than 10, and since you are reading this left to right, obviously, we do not live in a universe sized minkowski space time model. This kind of defeats its potential as being a useful model of our universe.
What I was commenting earlier on is that it is silly for mathematicians to subscribe to such broken toy model universes where a simple logical fixed progression like counting is impossible and prevents the possibility of the very math they are using to make the stupid model with.
Physics has truly devolved into mastabatory contortionist yoga, where bragging about how many simultaneous contradictory pretzels you can tie yourself mathematically into is considered a professional accomplishment.
1. Thanks, got it---except for the specifically relativistic portions, which should come in handy, actually helpful to keep in mind, when I come to read on it (some time later, may be).
But yes, I can already see that space and time are not on the equal footings.
Objects would have extensions and locations, and hence, you would have the *physical* space even in a *fully* changeless universe, even though there wouldn't be time in it.
Time is only the common measure of the relative speediness of changes in the universe.
2. As to that Yoga thingie (or the reference you make to masturbation, perhaps due to an influence of Feynman's?).
Guess that's how they project and/or perceive Yoga in the USA. I do believe that preachers of yoga are also responsible for this state of affairs, as would be the preachers of other religions.
If I may add: Yoga refers to the integration of the mind and the body. Pronounced like "yog" not "yogaa". Is the etymological root for the English "yoke". The word "yog" by itself means "joining" or "connection or integration of a duality or of two otherwise seemingly disparate aspects."
Yoga refers to mind-body connection. Not to physical postures. It's not a meaningless or purposeless set of body-contorting (purely) physical exercises.
The essential idea is this: There always goes a very bodily component to every psychological state---to every emotion, thought---at least the stronger ones. You never experience consciousness without there being some automatic bodily actions that accompany it. The kinesthetic actions are just a part of it all.
The bodily response is rather automatic or "dumb"; it seems to follow on its own. People "automatically" jump to the feet when they hear/see some exciting thing (hence that stadium-related fallacy).
Yoga realizes that the mind-body connection can and does work both ways, and hence can be used for the betterment of the more subtle aspects of the connection, taking it in reverse: the bodily, emotional, as well as the more general body-mind related connections.
The idea in yogic postures, in particular, is to undertake those bodily arrangements which, when done systematically (even scientifically), puts the body-mind connection (in the reverse) in that mode whereby desirable body-chemical or mental effects do follow at a deep level. That's for postures.
Do them only if you find that you can do them right, and only if you have evidence for yourself that it directly benefits you. People from India on the spiritual path always report that they do benefit. Note, the "purely" bodily functioning can improve too.
Here, at a personal level, throughout school (up to X), I had a kind of an acidity problem. If I would stay up "late, say beyond say 8:30 PM, the next morning, I would have nausea, even omitting. I should know, because it was only rarely that I would stay up up to 09:00 PM, mostly to finish a songs program on the radio (the Binaca songs program). I hardly if ever studied in school beyond 07:00 PM.
I then did systematic yoga in XI and XII. Not very regularly, but sure enough, for about 2--3 months of practice at a time. I also took a general Ayurvedic tonic ("chyavanapraash") for acidity problems, regularly. It took care of my acidity problems *permanently*. I even began pulling all-nighters, for course submissions, once I was in COEP (my UG engg. school). Later on, too, I've done ``soorya namaskar''s, though strictly speaking, it's not ancient yoga: it was invented in the early 19th century. It too is beneficial. I still do it (though not very regularly). Yes, you can skip saying "om", if you wish in it.
My use of the word 'yoga' was entirely sarcastic. It was meant to be a visual joke painted in words.