I disagree with arguments of the form “My experience doesn’t look like that of a Boltzmann brain, so I’m not a Boltzmann brain”. If you were a Boltzmann brain, nothing you would think you know about physics or probability would actually be valid, nor would you have any capability to reason about the experience of a typical Boltzmann brain.
Perhaps the following definition can clarify the issue: say someone is “reasonable” if their experience correlates somehow with reality, and they have the ability to reason somewhat soundly (this concept was probably already given some other name, which I’m not familiar with). For instance, a Boltzmann brain is not reasonable (and you can imagine other possibilities for non-reasonable beings). It seems to me like any argument whatsoever must start with the hidden premise: “you are reasonable”. If you are not reasonable, then anything you make of the argument is worthless.
Therefore, the argument “your experience doesn’t look like that of a Boltzmann brain, hence you are not one” really works as follows:
Premise: you are reasonable.
Thus, what you know about physics, brains and probability is trustworthy, as are your reasoning capabilities.
Given that knowledge, you would expect the experience of a Boltzmann brain to be much less orderly then yours.
Hence, you are not a Boltzmann brain.
But this just proves being resonable implies not being a Boltzmann brain, which is trivial.
The concept of a Boltzmann brain can still be useful in an argument regarding a certain physical theory predicting their existence, like:
Premise: you are reasonable.
The theory predicts the vast majority of consicous beings would be Boltzmann brain.
But you are not a Boltzmann brain (by the premise, not by argument).
I disagree with arguments of the form “My experience doesn’t look like that of a Boltzmann brain, so I’m not a Boltzmann brain”. If you were a Boltzmann brain, nothing you would think you know about physics or probability would actually be valid, nor would you have any capability to reason about the experience of a typical Boltzmann brain.
Perhaps the following definition can clarify the issue: say someone is “reasonable” if their experience correlates somehow with reality, and they have the ability to reason somewhat soundly (this concept was probably already given some other name, which I’m not familiar with). For instance, a Boltzmann brain is not reasonable (and you can imagine other possibilities for non-reasonable beings). It seems to me like any argument whatsoever must start with the hidden premise: “you are reasonable”. If you are not reasonable, then anything you make of the argument is worthless.
Therefore, the argument “your experience doesn’t look like that of a Boltzmann brain, hence you are not one” really works as follows:
Premise: you are reasonable.
Thus, what you know about physics, brains and probability is trustworthy, as are your reasoning capabilities.
Given that knowledge, you would expect the experience of a Boltzmann brain to be much less orderly then yours.
Hence, you are not a Boltzmann brain.
But this just proves being resonable implies not being a Boltzmann brain, which is trivial.
The concept of a Boltzmann brain can still be useful in an argument regarding a certain physical theory predicting their existence, like:
Premise: you are reasonable.
The theory predicts the vast majority of consicous beings would be Boltzmann brain.
But you are not a Boltzmann brain (by the premise, not by argument).
Hence, the physical theory is likely wrong.