I’m pretty sure that you don’t understand the problem being discussed, but that’s an uncharitable impression. Could you indulge me in some further explanation of what you mean by, say, the reference to affine spaces?
I’m pretty sure that you don’t understand the problem being discussed
That’s quite possible, though, having studied some General Relativity, I probably understand a bit more about time than an average philosopher.
Could you indulge me in some further explanation of what you mean by, say, the reference to affine spaces?
Indulging, quoting some Wikipedia:
A-series (non-affine) “is past”, “is present” and “is future.” Here there is a fixed (for a given time) origin.
B-series (affine): “comes before” (or precedes) and “comes after” (or follows). Here there is no fixed origin (no “fundamental difference between past and future”, whatever the vague term “fundamental” might mean).
That’s quite possible, though, having studied some General Relativity, I probably understand a bit more about time than an average philosopher.
I’d love to ask you some questions about that, average philosopher to physicist.
Indulging, quoting some Wikipedia:
Okay, so given the distinction between affine and non-affine spaces, the question which (I think) remains is whether or not time is an affine space or a non-affine space. How is that to be resolved?
Right, A-theory’s origin has to be ‘the present moment’. I think A theory probably even excludes the possibility of a beginning of time (Hawking once wrote an article in which he had to coin the phrase ‘imaginary time’ to discuss the question of how long ago the big bang was). I’m sure that’s not an uncontroversial claim though.
This may seem like a kind of fringe metaphysical concern (and it’s certainly a metaphysical concern), but I think the question of the reality of change is probably the original philosophical problem.
Ahh, that. What would be an empirical difference between the two? If none, then there is nothing to resolve.
But that’s the whole question: is it affine or non-affine?
As to what empirical difference it makes (and whether or not ‘none’ means that the question is meaningless) is I suppose a matter for another survey question.
But, if you think Julian Barbour or EY are generally on the right track about the implications of quantum physics, then you’re a B-theorist. Fundamentally, the rejection of A-theory is the rejection of the reality of change. If you’re a B-theorist, change is on the map, but not anywhere in the territory.
Ah, again. See, it matters to me not in the least whether it’s A or B or something else, if they predict all the same things. (As far as I can tell, they predict nothing of consequence, so they are not interesting at all.) As for Barbour, his models have nothing testable in them, as far I know (replace time with “change”? so?), which is a big negative against them. Whether the “block universe” notion is a good one still remains to be seen, so far it is not instrumentally useful. I do not understand EY’s fascination with Barbour. At least MWI, when taken literally, has a chance of being falsifiable.
I’m pretty sure that you don’t understand the problem being discussed, but that’s an uncharitable impression. Could you indulge me in some further explanation of what you mean by, say, the reference to affine spaces?
That’s quite possible, though, having studied some General Relativity, I probably understand a bit more about time than an average philosopher.
Indulging, quoting some Wikipedia:
A-series (non-affine) “is past”, “is present” and “is future.” Here there is a fixed (for a given time) origin.
B-series (affine): “comes before” (or precedes) and “comes after” (or follows). Here there is no fixed origin (no “fundamental difference between past and future”, whatever the vague term “fundamental” might mean).
I’d love to ask you some questions about that, average philosopher to physicist.
Okay, so given the distinction between affine and non-affine spaces, the question which (I think) remains is whether or not time is an affine space or a non-affine space. How is that to be resolved?
It does have an origin (the Big Bang) if you will, but that’s not the kind of origin you’d need for A-theory to make sense.
Right, A-theory’s origin has to be ‘the present moment’. I think A theory probably even excludes the possibility of a beginning of time (Hawking once wrote an article in which he had to coin the phrase ‘imaginary time’ to discuss the question of how long ago the big bang was). I’m sure that’s not an uncontroversial claim though.
This may seem like a kind of fringe metaphysical concern (and it’s certainly a metaphysical concern), but I think the question of the reality of change is probably the original philosophical problem.
First, I would not want to give a wrong impression. While I do have a PhD, physics is not my day job.
Ahh, that. What would be an empirical difference between the two? If none, then there is nothing to resolve.
But that’s the whole question: is it affine or non-affine?
As to what empirical difference it makes (and whether or not ‘none’ means that the question is meaningless) is I suppose a matter for another survey question.
But, if you think Julian Barbour or EY are generally on the right track about the implications of quantum physics, then you’re a B-theorist. Fundamentally, the rejection of A-theory is the rejection of the reality of change. If you’re a B-theorist, change is on the map, but not anywhere in the territory.
Ah, again. See, it matters to me not in the least whether it’s A or B or something else, if they predict all the same things. (As far as I can tell, they predict nothing of consequence, so they are not interesting at all.) As for Barbour, his models have nothing testable in them, as far I know (replace time with “change”? so?), which is a big negative against them. Whether the “block universe” notion is a good one still remains to be seen, so far it is not instrumentally useful. I do not understand EY’s fascination with Barbour. At least MWI, when taken literally, has a chance of being falsifiable.
I think that’s a pretty good ‘other’ answer to the question. Thanks for taking the time.