The discussion centers on the Block Universe Theory, which posits that past, present, and future coexist simultaneously, with time being an emergent property rather than a fundamental one. Participants debate the implications of the second law of thermodynamics on this theory, particularly how entropy increases can be reconciled with the notion of a block universe. The argument presented suggests that while entropy distribution is fundamental, the directionality of time is merely a perception, allowing for a model where entropy increases along a spatial coordinate that can be reinterpreted as time.
PREREQUISITESPhysicists, philosophers of time, and students of thermodynamics seeking to understand the relationship between entropy and the Block Universe Theory.
What would an increase of entropy have against the block universe?Ebi Rogha said:Summary:: I understand “Block Universe Theory” says past, present and future all exist together and time is emergent (and not fundamental).
I wonder how physicists who support this theory explain the increase of entropy?
What I mean is the 2nd law of thermodynamics gives a direction to time, it can travel only in one direction. Does not this mean time is fundumental and all states can not exist together?Dale said:What would an increase of entropy have against the block universe?
On my house I have a block of wood trim that the top is well sheltered from the rain and the bottom is exposed to rain. So it deteriorates on the bottom but the top is pristine. So a block of wood can be nice and neat on one side and all messy on the other side.
Similarly a block of universe can have low entropy on one side and high entropy on the other side. Blocks need not be
The argument I'm familiar with here is that the distribution of entropy within the block is fundamental, but the direction of time isn't. The perception of which direction time goes is just that - a perception. It follows increasing entropy, because formation of memories involves increasing entropy. As far as the block universe is concerned, it doesn't care about directionality to time - it just is.Ebi Rogha said:What I mean is the 2nd law of thermodynamics gives a direction to time, it can travel only in one direction. Does not this mean time is fundumental and all states can not exist together?
In other words, the block universe makes no difference between past, present and future, it means time is bidirectional and we should be able to go back in time. Am I missing something?
That is not a correct inference of what the Block universe means. If I stack a bunch of Legos together then my block of Legos has a definite top and a definite bottom. Being a block in no way implies the symmetry you are asserting.Ebi Rogha said:the block universe makes no difference between past, present and future, it means time is bidirectional
Imagine a box in which entropy does not change with time, but increases from the left to the right. One would say that entropy increases with ##x##. The ##x## is just a coordinate. Now change the name of this coordinate, i.e. call it ##t##. That's a simple model for a block universe with a time arrow.Ebi Rogha said:Summary:: I understand “Block Universe Theory” says past, present and future all exist together and time is emergent (and not fundamental).
I wonder how physicists who support this theory explain the increase of entropy?