Is Probability Relative?

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Discussion Overview

The discussion centers around the concept of whether probability can be considered relative, particularly in the context of different observers in physics. Participants explore implications for the unification of quantum mechanics and relativity, as well as the role of prior information in determining probabilities.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Mathematical reasoning

Main Points Raised

  • Some participants propose that the probability of an event may differ for various observers, suggesting a connection to the unification of quantum mechanics and relativity.
  • One participant suggests that for two inertial observers, the probability distribution remains consistent across different frames, as modified by Lorentz transformations.
  • Another participant emphasizes that the question may not belong in the math forum, arguing that mathematics does not dictate physical possibilities.
  • Some participants mention Bayesian statistics and conditional probabilities as frameworks where probabilities can differ based on prior information available to observers.
  • Bertrand's Paradox is introduced as an example illustrating how different interpretations of randomness can lead to varying answers regarding probability.
  • One participant speculates on a connection between different types of infinities (Aleph1 and Aleph0) in relation to probabilities.
  • A question is raised regarding the statement "Choice Changes Chance," inviting further exploration of its implications.

Areas of Agreement / Disagreement

Participants express differing views on the nature of probability and its relativity, with no consensus reached on the implications for physical theories or the interpretation of specific paradoxes.

Contextual Notes

Some assumptions about the nature of probability and the definitions of randomness are not fully explored, leaving room for ambiguity in the discussion.

Loren Booda
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Is it possible for the probability of an event to be relative, i. e. valued differently for different objective observers? Does this say anything pertinent about the feasibility of unifying quantum mechanics and relativity?
 
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Just doing the calculations informally in my head, it seems to me, that for two inertial observers, of a same quantum phenomenon, the probability distribution is modified just so that an event happens at (x,t) in S with probability P, then it happens in at (x',t') in S' with the same probability, where (x',t') is related to (x,t) by a Lorentz transformation.

But what I don't understand is why you posted the question in the math forum. It is not the task of math to say what is and what is not physically possible. A mathematician just has to say "Let P1 be the probability of the event according to S and let P' be the probability of the event according to S'" and it's done.
 
quasar987,

On second thought, I should have posted this in the General Physics forum. Maybe a moderator will transfer it there.
 
You can always report your own post. Hit the Report button under your little medal name and say this post belongs in the GR forum. I do it all the time.
 
Probabilities can be different for two different observers if they have access to different prior information.

Look at Bayesian statistics and conditional probabilities.
 
Loren Booda said:
Is it possible for the probability of an event to be relative, i. e. valued differently for different objective observers?

Please have a look at Bertrand's Paradox. Depending on the notion of randomness of the observer, the problem has three different answers.
 
My SWAG on Bertrand? Something to do with Aleph1 probabilities expressed as those of Aleph0.
 
Last edited:
Of what veracity is the statement "Choice Changes Chance"?
 

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