/sci/ - Science & Math

>>6361679

>>6362380
determinism is understood in terms of predictability. Predictability happens if the equations of motion for field operators are hyperbolic; this happens in 1+n and n+1 dimensions. Modern determinism is a probabilistic determinism, coherently with QM being a generalization of probability theory. The connection with free will that you make is unjustified, also it's not science, to nitpick.

Determinism has paradoxically actually very little to do with time. It has to do with the uniqueness and existence in an open set of solutions to a diff eq given a certain type of conditions on a certain kind of boundary. Our modern understanding of (flat space) relativistic QM is that of a theory about correlation of measurements at different events in spacetime. (QM in curved s-t is another kind of beast.) The Universe, in this sense, looks pretty much deterministic.

However.

If you have a spacetime with closed timelike curves, determinism looks very very weird. I refer to the works of Novikov and others. Basically the timeline looping on itself it's self consistent, but there are probably always an infinite number of selfconsistent configurations given fixed boundary (read: "initial") conditions. This is difficult to interpret classically; here is where QM has an important effect and solves the paradoxes in terms of interference between paths in configuration space.

The fact that QM has a global, important effect whenever you try to timetravel is in fact why I have a strong gut feeling that time travel is not possible and the chronology protection conjecture is enforced by macroscopic quantum phenomena at the cauchy surface of the boundary of the region with CTCs that destroy the machine. Sorry, digression.

ITT: /sci/ humor.