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Eternal Return

by steenpat
Tags: eternal, return
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Feb6-11, 07:34 AM
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Quote Quote by brainstorm View Post
"Just sayin?" Dawg, plz! Well, don't you see a connection between living life affirmatively and without regret and living ethically in a way that you would never regret affecting someone else in a way that you wouldn't want to be affected by others? Typically I associate this philosophy of "living life to its fullest" with the idea that one day you will die and lose the chance." Eternal return promotes more the idea that you will not only not lose the chance to live life in every possible way; you will not be able to avoid having the opportunity to make every possible choice and experience every possible choice made by someone else. So would you regret the way you lived if it was guaranteed to affect you the way it affects others at some point in the future?
I don't know what this means.
Feb7-11, 10:03 AM
P: 1,117
Quote Quote by JoeDawg View Post
I don't know what this means.
Maybe you should do a little work to explain your misunderstanding, then. Or else you shouldn't post such a comment. It puts the burden on me to go back and re-explain my post in another way. Why should I have to do that after I explained it already once? Is there a specific sentence or concept that you don't understand?
Feb8-11, 01:24 PM
P: 84
If the total energy in the universe is conserved, then it's a sum of universe's potential and exerted energy quantities. The universe is expanding, energy is exerted and thus the potential energy is decreased. When the potential energy is zero, then the universe may cease to exist or it may reverse back in time.
Feb9-11, 12:42 AM
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Quote Quote by steenpat View Post
I'm sure this topic has been talked about ad infinitum, but I'd like to suggest a new angle.
Here, I will be referencing the work of Nietzsche (actually from Indian philosophers originally), and the concept which posits that the universe has been recurring, and will continue to recur, in a self-similar form an infinite number of times across infinite time and or infinite space.

Poincare's theorem of recurrence is what gives strength to this concept, as it states that certain systems will, after a sufficiently long time, return to a state very close to the initial state. (

However, according to some critics, the second law of thermodynamics says this can't happen since entropy can never decrease. (same wiki entry but no citation).

Now, is it necessary that entropy would need to decrease in order for a recurrence to happen? Assuming the state of the universe has a finite amount of configurations, and that energy is conserved, given a long enough time frame then could these configurations come close to their original form once more as a natural progression of the system?

It seems that current cosmology models would destroy this concept by the simple fact that the universe will reach a heat death scenario (, in which case it doesn't seem like any matter will be around to make reconfigurations possible in the future.

But, if quantum fluctuations can create more big bangs, and this can seemingly happen an infinite amount of times without any restriction, it would seem inevitable that everything would recur arbitrarily close, wouldn't it? (

I don't know if my reasoning is correct, maybe someone else can add a little input. I suppose that Poincare recurrence if possible, doesn't describe Eternal Return so much as Eternal Alternatives.
1. Poincare recurrence is about systems defined by completely deterministic differential equations; classical physics. There's no reason to expect it to apply to the conditions from big bang to today-here.

1a. Poincare's recurrence pertains to dynamical systems, so a system that reaches a stable state and then stops being dynamic does not count (the point is that it has to go somewhere and it can't intersect itself or it wouldn't be deterministic... but then it's also confined to an area of state-space, so it must keep moving around without intersecting an old path... so much movement without retracing old paths then there's no option... it must either reach every neighborhood or stop... and not be a dynamical system anymore.)

2. 2nd law of thermodynamics is more of an observation than a law, classically. Since they're reversible deterministic systems, it's not physically impossible that all particles in a box go back to their original point in the corner of the box; it's just very highly unlikely. So there's really no classical prediction that says the 2nd law must be, just a probabilistic tendency based on statistical mechanics.

To my mind, to really justify the 2nd law requires quantum physics... a literal loss of information below the Planck area (area of phase-space: x vs. p) due to HUP/indistinguishability.
Mar8-12, 06:20 PM
P: 27
Quote Quote by steenpat View Post

Poincare's theorem of recurrence is what gives strength to this concept, as it states that certain systems will, after a sufficiently long time, return to a state very close to the initial state. (
A conclusion is no stronger than its premisses...
We simply dont live in the world described by Poincare!

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