The block universe (temporary name)
The aim of this essay is to argue against the metaphysical picture of the block universe. I'm writing this for people like Andrei, who recognize that there is some sort of contradiction with determinism, but have no clue how to reconcile it with what we know about physics.
Maybe I should title it "the arrogance of modern physics." It's so ridiculous for them to say we know everything except for like dark matter and confinement and quantum gravity and times earlier than the first 10^-47 seconds of the Big Bang. Everything else is jUsT aN eNgInEeRiNg pRoBlEm.
I'm only going to cover classical physics in this essay. Quantum physics makes everything way more confusing, and I don't think it ultimately would be relevant for the key points of my argument.
The first initial condition
Physics doesn't explain the Big Bang
The nature of time
Time is motion. A measurement of how much time has passed is a quantitative identification of how much motion has happened. To say "it has been 30 seconds" is to say that the second hand has moved halfway across the clock.
In reality, there is no such thing as an instant in time. No one has ever observed one, and no one ever could even in principle. An instant is an idealization, corresponding to an arbitrarily small amount of motion. This idealization is clearly useful for many things, but no one knows precisely what its domain of validity is.
A corollary of the above is that in reality, there is no such thing as the state of a physical system at some instant in time. Again, the concept of an instantaneous state is a useful idealization, but its domain of validity remains unclear.
Obviously, I can't paint a precise picture of what it looks like when this picture breaks down. If I could, I would be the next Isaac Newton. But to jog the reader's imagination, I will concoct a fictional story:
Suppose we have a system consisting of many parts that are moving independently. Each part alternates between going through some fixed motion which takes time to complete, and doing nothing at all. The parts act asynchronously. Next, I want to say what the state of the system is at time , but I can't do that, because I'm keeping firmly in mind the fact that such a thing is an idealization.
There's no such thing as the state