Boltzmann brains and other low probability events

Click For Summary

Discussion Overview

The discussion centers around the concept of Boltzmann brains (BBs) and the implications of low probability events in quantum mechanics (QM) and cosmology. Participants explore the realism of expecting such events to occur, the philosophical implications, and the definitions surrounding BBs.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Exploratory

Main Points Raised

  • Some participants question the realism of expecting Boltzmann brains and other low probability events to occur, suggesting that this depends on interpretations of quantum mechanics.
  • There is a view that the theory of QM predicts probabilities but does not define what is "realistic," indicating a need for a more comprehensive theory.
  • One participant expresses skepticism about the significance of BBs, likening the discussion to philosophical concepts like solipsism and emphasizing the importance of established physics over speculative ideas.
  • Another participant raises several questions regarding BBs, including their certainty in an infinite universe, their physical possibility, and the implications of an eternal universe on the number of BBs.
  • Concerns are raised about the concept of infinity in relation to physical theories, with some arguing that theories relying on infinity are not meaningful.
  • There is a discussion about the restrictive definitions of a Boltzmann brain, with contrasting views on whether our brains could be considered BBs based on different interpretations of randomness and order in the universe.

Areas of Agreement / Disagreement

Participants express a range of opinions on the existence and implications of Boltzmann brains, with no clear consensus reached. Some agree on the speculative nature of the topic, while others challenge the validity of the assumptions involved.

Contextual Notes

Participants note the lack of established answers to related questions, highlighting the uncertainty and varying interpretations surrounding the concept of Boltzmann brains and low probability events.

  • #31
durant35 said:
but because of their random wavefunctions.

Random wave-functions?

I like to think I know QM pretty well to the level of Ballentine, but I think that one needs further elaboration.

Please no links to papers - it should be explainable without that.

Thanks
Bill
 
Physics news on Phys.org
  • #32
bhobba said:
Random wave-functions?

I like to think I know QM pretty well but I think that one needs further elaboration.

Please no links to papers - it should be explainable without that.

Thanks
Bill

My bad, error in writing. I didn't really mean that wavefunctions are random.
 
  • #33
durant35 said:
Now my question is: do those fluctuations include both classical thermal fluctuations (the one which Boltzmann originally had in mind) and also quantum fluctuations (where unlikely things occur because of the randomness of the particle-wavefunctions).
durant35 said:
My bad, error in writing. I didn't really mean that wavefunctions are random.

Sean is a very serious scientist - his GR textbook is VERY good.

But I must say I find some of his QM writings on the obscure side with this thread an example. A lot of stuff like randomness of the particle-wavefunctions leave me scratching my head exactly what is meant. Wavefunctions change either by Schrödinger's equation or some kind of preparatiom procedure - at least that's the modern view found in texts like Ballentine. Does he mean the result of preparation procedures is random?

Thanks
Bill
 
  • #34
durant35 said:
What's your opinion on BBs in general?
If you are Boltzmann brains then all your knowledge about science is fiction including unjustified extrapolations that lead to speculation about Boltzmann brains. Idea sort of defeats itself.
 
  • Like
Likes   Reactions: stoomart
  • #35
My view is that it'll never happen even if it's theoretically possible. A common complaint among fundamentalists who don't understand evolution is that the odds of atoms randomly creating a mind as complex as us is ridiculously unlikely. I agree. Without an iterative, self-propelling process like Darwinian evolution, objects will remain simple. Even if a thought formed randomly, why would it not dissipate instantly? It has to be self-containing in order to have a stream of consciousness.
 
  • #36
newjerseyrunner said:
My view is that it'll never happen even if it's theoretically possible. A common complaint among fundamentalists who don't understand evolution is that the odds of atoms randomly creating a mind as complex as us is ridiculously unlikely. I agree. Without an iterative, self-propelling process like Darwinian evolution, objects will remain simple. Even if a thought formed randomly, why would it not dissipate instantly? It has to be self-containing in order to have a stream of consciousness.

I agree with you.

Would you agree that we need a better understanding of evolution, entropy and their relationship in order to have a legitimate discussion about something that sounds very drastic and extraordinary like a BB?
 

Similar threads

  • · Replies 23 ·
Replies
23
Views
2K
Replies
6
Views
794
  • · Replies 8 ·
Replies
8
Views
1K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 13 ·
Replies
13
Views
2K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 15 ·
Replies
15
Views
3K
  • · Replies 25 ·
Replies
25
Views
6K
  • · Replies 2 ·
Replies
2
Views
5K