There is a relevant distinction: the machinery being used (logical assignment) has to be stable for the duration of the proof/computation. Or perhaps, the “consistency” of the outcome of the machinery is defined on such a stability.
For the original example, you’d have to make sure that you finish all relevant proofs within a period in Monday or within a period in NotMonday. If you go across, weird stuff happens when attempting to preserve truth, so banning non-timeless propositions makes things easier.
You can’t always walk around while doing a proof if one of your propositions is “I’m standing on Second Main”. You could, however, be standing still in any one place whether or not it is true. ksvanhorn might call this a space parametrization, if I understand him correctly.
So here’s the problem: I can’t imagine what it would mean to carry out a proof across Everett branches. Each prover would have a different proof, but each one would be valid in its own branch across time (like standing in any one place in the example above).
I think a refutation of that would be at least as bizarre as carrying out a proof across space while keeping time still (note: if you don’t keep time still, you’re probably still playing with temporal inconsistencies), so maybe come up with a counterexample like that? I’m thinking something along the lines of code=data will allow it, but I couldn’t come up with anything.
Sure, but I don’t think anyone was talking about problems arising from Sleeping Beauty needing to do a computation taking multiple days. The computations are all simple enough that they can be done in one day.
I’d say your reply is at least a little bit of logical rudeness, but I’ll take the “Sure, …”.
I was pointing specifically at the flaw* in bringing up Everett branches into the discussion at all, not about whether the context happened to be changing here.
I wouldn’t really mind the logical rudeness (if it is so), except for the missed opportunity of engaging more fully with your fascinating comment! (see also *)
It’s also nice to see that the followup to OP starts with a discussion of why it’s a good/easy first rule to, like I said, just ban non-timeless propositions, even if we can eventually come with a workable system that deals with it well.
(*) As noted in GP, it’s still not clear to me that this is a flaw, only that I couldn’t come up with anything in five minutes! Part of the reason I replied was in the hopes that you’d have a strong defense of “everettian-indexicals”, because I’d never thought of it that way before!
Hmm. I don’t think I see the logical rudeness, I interpreted TAG’s comment as “the problem with non-timeless propositions is that they don’t evaluate to the same thing in all possible contexts” and I brought up Everett branches in response to that, I interpreted your comment as saying “actually the problem with non-timeless propositions is that they aren’t necessarily constant over the course of a computation” and so I replied to that, not bringing up Everett branches because they aren’t relevant to your comment. Anyway I’m not sure exactly what kind of explanation you are looking for, it feels like I have explained my position already but I realize there can be inferential distances.
“the problem with non-timeless propositions is that they don’t evaluate to the same thing in all possible context
It’s more
“the problem with non-timeless propositions is that they don’t evaluate to the same thing in all possible context AND a change of context can occur in the relevant situation”.
No one knows whether Everett branches are, or what they are. If they are macroscopic things that remain constant over the course of the SB story, they are not a problem....but time still is, because it doesn’t. If branching occurs on coin flips, or smaller scales, then they present the same problem as time indexicals.
Right, so it seems like our disagreement is about whether it is relevant whether the value of a proposition is constant throughout the entire problem setup, or only throughout a single instance of someone reasoning about that setup.
The first case has a truth value that varies with time.
And the second case has a truth value that varies depending on what Everett branch you are in. Does it matter?
There is a relevant distinction: the machinery being used (logical assignment) has to be stable for the duration of the proof/computation. Or perhaps, the “consistency” of the outcome of the machinery is defined on such a stability.
For the original example, you’d have to make sure that you finish all relevant proofs within a period in Monday or within a period in NotMonday. If you go across, weird stuff happens when attempting to preserve truth, so banning non-timeless propositions makes things easier.
You can’t always walk around while doing a proof if one of your propositions is “I’m standing on Second Main”. You could, however, be standing still in any one place whether or not it is true. ksvanhorn might call this a space parametrization, if I understand him correctly.
So here’s the problem: I can’t imagine what it would mean to carry out a proof across Everett branches. Each prover would have a different proof, but each one would be valid in its own branch across time (like standing in any one place in the example above).
I think a refutation of that would be at least as bizarre as carrying out a proof across space while keeping time still (note: if you don’t keep time still, you’re probably still playing with temporal inconsistencies), so maybe come up with a counterexample like that? I’m thinking something along the lines of code=data will allow it, but I couldn’t come up with anything.
Sure, but I don’t think anyone was talking about problems arising from Sleeping Beauty needing to do a computation taking multiple days. The computations are all simple enough that they can be done in one day.
I’d say your reply is at least a little bit of logical rudeness, but I’ll take the “Sure, …”.
I was pointing specifically at the flaw* in bringing up Everett branches into the discussion at all, not about whether the context happened to be changing here.
I wouldn’t really mind the logical rudeness (if it is so), except for the missed opportunity of engaging more fully with your fascinating comment! (see also *)
It’s also nice to see that the followup to OP starts with a discussion of why it’s a good/easy first rule to, like I said, just ban non-timeless propositions, even if we can eventually come with a workable system that deals with it well.
(*) As noted in GP, it’s still not clear to me that this is a flaw, only that I couldn’t come up with anything in five minutes! Part of the reason I replied was in the hopes that you’d have a strong defense of “everettian-indexicals”, because I’d never thought of it that way before!
Hmm. I don’t think I see the logical rudeness, I interpreted TAG’s comment as “the problem with non-timeless propositions is that they don’t evaluate to the same thing in all possible contexts” and I brought up Everett branches in response to that, I interpreted your comment as saying “actually the problem with non-timeless propositions is that they aren’t necessarily constant over the course of a computation” and so I replied to that, not bringing up Everett branches because they aren’t relevant to your comment. Anyway I’m not sure exactly what kind of explanation you are looking for, it feels like I have explained my position already but I realize there can be inferential distances.
It’s more “the problem with non-timeless propositions is that they don’t evaluate to the same thing in all possible context AND a change of context can occur in the relevant situation”.
No one knows whether Everett branches are, or what they are. If they are macroscopic things that remain constant over the course of the SB story, they are not a problem....but time still is, because it doesn’t. If branching occurs on coin flips, or smaller scales, then they present the same problem as time indexicals.
Right, so it seems like our disagreement is about whether it is relevant whether the value of a proposition is constant throughout the entire problem setup, or only throughout a single instance of someone reasoning about that setup.