Gary O'Reilly

Give me some more.

Ready for the next one.

Right.

This is from Andrew D. Greetings, Drs.

Tyson, Lou, and of course, Lord Nice.

Andrew Dack from Minneapolis.

Well, stay safe and stay warm, sir.

The question goes as such.

Yes.

The path integral formulation calculates probabilities by summing overall possible paths a particle could take.

The two-state vector formalism describes quantum systems using both a forward-evolving state from the past and a backward-evolving state from the future.

Both suggest quantum mechanics can be written with boundary conditions at both ends of time, not just initial conditions.

It goes on.

Sorry about this being as long as it is, but it's complicated.

No, no, no.

Has this led to experimental predictions that differ from standard quantum mechanics?

And do physicists take retrocausality seriously as part of reality's actual structure?

Could retrocausality be evidence of a four-dimensional deterministic universe where the indeterminacy we observe is just our limited perspective of a structure that is already complete?

Are we ready for another question?

Yeah, bring it on.