“Anaximander and the Birth of Science” by Carlo Rovelli

The difficulty in understanding the complexity of the notion of simulataneity in Einstein’s theory is very much analogous to the difficulty in understanding the notions of “up” and “down” in Anaximander‘s new cosmological theory. If the relativity of “up” and “down” nowadays seems fairly easy to understand, while the relativity of simultaneity is still harder to grasp for those who are not professional physicists, this is only because Anaximander’s theory and its developments have been digested for twenty-six hundred years, while Einstein’s it not yet widely assimilated. But we are dealing with the same conceptual path. The difference is that Einstein based his work on observations already fully codified in Maxwell’s theories and the mechanics of Galileo and Newton, while Anaximander based is only on the observation of the rising and setting of the stars.

– Carlo Rovelli, “Anaximander and the Birth of Science”, Chapter 4: Earth Floats in Space, Suspended in the Void

I just read the first couple paragraphs of the Wikipedia article for Relativity of Simultaneity.

Wikipedia of course gives a better short summary but if I were to try to summarize this principle: Every event happens at a different for me than it does for you. There is no “common” now between us.

I am not a professional physicist but this is not the first time that I’ve heard this idea (I read The Order of Time by Carlo and I’ve heard explanations of and implications of Einstein’s theories here and there over the last 25 years, going back to the last year’s of high school for me.

And still I find this idea absolutely… not preposterous but… I would say “hard to swallow.”

For one, I can see video of astronaut’s floating in space and it’s not hard for me to understand that there is no “up” and “down” for someone in the floating in the space station, there are instead only relationships: “the coffee is on my left, I know that the donuts are opposite the coffee, so they must be on my right, but the sugar that is adjacent to each, it could be above or below me, I need one more reference point, I could be floating either way.”

That much I can understand. Barely…

The idea that there is no common “now” is much harder for me to understand. Actually… I don’t really “understand” it, meaning that I still don’t know it to be true, as if it were obvious.

Carlo uses the word “analogous” but I think he takes a lot of liberty here. No matter how long I had been taught or what I had been taught and for how long I had been taught it, I think the relativity of simultaneity is a much harder idea to grasp.

I can see videos of the astronauts and I can play video games flying a space shit through space and so I have a perceptual way that I can understand this idea of the relativity of “up” and “down” True… in Anaximander’s time (610 to 545 BC, or about 2600 years ago) no one had video of astronaut’s and no one had space pilot video games.

But what about birds? Or better, what about fish? In all times, if you told someone “when a fish is swimming, it doesn’t make so much difference to the fish if it’s upside down or not.” That is an understandable idea.

But then: when the fly lands on the water, it lands at a different time for the fish. No way…

There is on way to experience anything like the relativity of time, and for me at least, perhaps that is why I see no easy way to make this concept “truly believable.”

If I’m being honest, I don’t understand the “curvature of space-time” either. Sure, I’ve seen the pictures of the bowling resting on the stretchy graph paper. But I suspect those who are not professional physicists (and even probably some professional physicists…) when they say “yes, I understand this” I think what they more accurately are saying is “I understand that that idea has been proven and if I were giving this as a question on a test, I could regurgitate the answer.”

One other quote I really liked:

Intelligence, used well and in conjunction with observation, frees us from an illusion, from a limited and partial view of the world.

– Carlo Rovelli, “Anaximander and the Birth of Sciece”, Chapter 4: Earth Floats in Space, Suspended in the Void