3 ms·

I have a different take on this, only half joking. What if time is a free variable - it can move forward and backwards freely, perhaps like a drunkards walk? T

I have a different take on this, only half joking. What if time is a free variable - it can move forward and backwards freely, perhaps like a drunkards walk? To a conscious being, any memory of having been at time t will be erased when t decreases. When t increases again, but you'll have no memory by which to detect the revisitation. I know that I just postulated that there is a time sequence by which the motion of time can be described. But that is only to make the idea graspable to our ordinary sense of time. One interpretation of what I described is the slab model of the universe where time is just another axis and the evolution along that line is fixed. Another interpretation would be that as time moves forward and backwards the state of the universe is free to change. In either case, our perception of our personal timelines would always appear to be unidirectional.

ClumsyPilot 2y ago
> Another interpretation would be that as time moves forward and backwards the state of the universe is free to change What would be the measurable effect of this - would casualty actually be broken? Would we get Dejavu?
n2e 2y ago
Anecdote, but this is how my observer experiences time.
- anodyne_one 2y ago
  What do you mean by this?
UltraSane 2y ago
The slab model of the universe is not compatible with quantum randomness.
- mitthrowaway2 2y ago
  Isn't it?
- drdeca 2y ago
  Hm, if you just consider unitary time evolution, I think it is compatible with quantum mechanics. "Psi(t) = U(t-t_0) Psi(t_0) for all real values for t" and all that. And, if you want to suppose objective collapse, I think you can still consider a probability distribution over histories, where each history could be considered as like, something like the described above Psi(t), except that if at time t_i some measurement is made with the outcome of the measurement being described with the projection P, then like, for t > t_i , Psi(t) = U(t-t_i) P U(t_i-t_0) Psi(t_0) = U(t-t_0) (U(t_i-t_0)^* P U(t_i - t_0)) Psi(t_0) = (U(t-t_i) P U(t-t_i)^*) U(t-t_0) Psi(t_0) , except add in a projection for each objective-collapse event. I guess you might also want to add in normalization factors. Also, I guess maybe one might want to make the collapse be a thing that is happening constantly to some extent or another? I think I saw something about the quantum zeno effect arguing that time evolution could be described in terms of constantly applying continuously varying projection operators. Now, in these cases, you wouldn't have the future deterministically determining the past, but you also don't have the past deterministically determining the future, so.. I think this seems like it could be considered a "slab model" or "block universe" in a reasonable sense? Though perhaps not in the sense you have in mind, but I don't know what about it fails to satisfy what you have in mind.

ClumsyPilot 2y ago

> Another interpretation would be that as time moves forward and backwards the state of the universe is free to change What would be the measurable effect of this - would casualty actually be broken? Would we get Dejavu?

n2e 2y ago

Anecdote, but this is how my observer experiences time.

anodyne_one 2y ago
What do you mean by this?

UltraSane 2y ago

The slab model of the universe is not compatible with quantum randomness.

mitthrowaway2 2y ago
Isn't it?
drdeca 2y ago
Hm, if you just consider unitary time evolution, I think it is compatible with quantum mechanics. "Psi(t) = U(t-t_0) Psi(t_0) for all real values for t" and all that. And, if you want to suppose objective collapse, I think you can still consider a probability distribution over histories, where each history could be considered as like, something like the described above Psi(t), except that if at time t_i some measurement is made with the outcome of the measurement being described with the projection P, then like, for t > t_i , Psi(t) = U(t-t_i) P U(t_i-t_0) Psi(t_0) = U(t-t_0) (U(t_i-t_0)^* P U(t_i - t_0)) Psi(t_0) = (U(t-t_i) P U(t-t_i)^*) U(t-t_0) Psi(t_0) , except add in a projection for each objective-collapse event. I guess you might also want to add in normalization factors. Also, I guess maybe one might want to make the collapse be a thing that is happening constantly to some extent or another? I think I saw something about the quantum zeno effect arguing that time evolution could be described in terms of constantly applying continuously varying projection operators. Now, in these cases, you wouldn't have the future deterministically determining the past, but you also don't have the past deterministically determining the future, so.. I think this seems like it could be considered a "slab model" or "block universe" in a reasonable sense? Though perhaps not in the sense you have in mind, but I don't know what about it fails to satisfy what you have in mind.