If I don’t understand how that can happen, then perhaps the problem is either (1) that it can’t or (2) that how it can is a subtle matter which hasn’t been explained well enough for me to understand it. So far, in this discussion, you’ve offered no reason to think #2 more likely than #1, and in any case you haven’t made any attempt to explain how it could happen.
The PDF does not appear to contain the sentence you purport to quote from it. (More specifically, it does not appear to contain the word “flips”. (Neither does the abstract.) In any case, its proposal seems to amount simply to redefining “time reversal”. If all you’re saying is that if you use “T symmetry” to mean what everyone else calls “CPT symmetry” then physics is likely to be T-symmetric but not CPT-symmetric, then (duh!) I agree, but I’m not sure why that’s supposed to be interesting.
The PDF does not appear to contain the sentence you purport to quote from it. (More specifically, it does not appear to contain the word “flips”.
Section 2.4 page 32. Searching for “flips” doesn’t work here either. Copy-n-paste into a text editor shows why—fi and fl are weird ligatures in this PDF.
In any case, its proposal seems to amount simply to redefining “time reversal”. If all you’re saying is that if you use “T symmetry” to mean what everyone else calls “CPT symmetry” then physics is likely to be T-symmetric but not CPT-symmetric, then (duh!) I agree, but I’m not sure why that’s supposed to be interesting.
To quote from the article:
We have articulated the `geometric’ notion of time reversal implicit in Malament’s work, according to which time reversal consists in leaving all [other] fundamental quantities alone, and merely flipping the temporal orientation.
It’s plainly proposing T symmetry. Does that help you to see how such a thing might be possible?
Aha, of course. (I did search for some other substrings, though I forget what. Presumably they also contained ligatures. D’oh.)
plainly proposing T symmetry
… in Malament’s proposal, which is not the same as the Feynman one you cite earlier. The purpose of the paper is to argue for a definitional change whereby we call “T” what is currently generally called “CT”. Everything in the paper is concerned with classical, not quantum, electrodynamics. The paper does not argue that T symmetry (as generally understood or with a revised definition) is plausibly true in quantum electrodynamics.
Does that help you to see how such a thing might be possible?
It would make this discussion more pleasant for me if you’d be less patronizing. Whether you care about that is, of course, up to you.
If I don’t understand how that can happen, then perhaps the problem is either (1) that it can’t or (2) that how it can is a subtle matter which hasn’t been explained well enough for me to understand it. So far, in this discussion, you’ve offered no reason to think #2 more likely than #1, and in any case you haven’t made any attempt to explain how it could happen.
The PDF does not appear to contain the sentence you purport to quote from it. (More specifically, it does not appear to contain the word “flips”. (Neither does the abstract.) In any case, its proposal seems to amount simply to redefining “time reversal”. If all you’re saying is that if you use “T symmetry” to mean what everyone else calls “CPT symmetry” then physics is likely to be T-symmetric but not CPT-symmetric, then (duh!) I agree, but I’m not sure why that’s supposed to be interesting.
Section 2.4 page 32. Searching for “flips” doesn’t work here either. Copy-n-paste into a text editor shows why—fi and fl are weird ligatures in this PDF.
To quote from the article:
It’s plainly proposing T symmetry. Does that help you to see how such a thing might be possible?
Aha, of course. (I did search for some other substrings, though I forget what. Presumably they also contained ligatures. D’oh.)
… in Malament’s proposal, which is not the same as the Feynman one you cite earlier. The purpose of the paper is to argue for a definitional change whereby we call “T” what is currently generally called “CT”. Everything in the paper is concerned with classical, not quantum, electrodynamics. The paper does not argue that T symmetry (as generally understood or with a revised definition) is plausibly true in quantum electrodynamics.
It would make this discussion more pleasant for me if you’d be less patronizing. Whether you care about that is, of course, up to you.