# Name of this probability paradox? **URL:** \ **Category:** Factual Questions\ **Created:** [April 9, 2009, 10:25pm UTC](https://boards.straightdope.com/t/name-of-this-probability-paradox/492573 "2009-04-09T22:25:37Z")\ **Posts on this page:** 6\ **Page:** 4
**Author:** ![Tyrrell\_McAllister](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tyrrell_mcallister/32/16772_2.png) [@Tyrrell\_McAllister](https://boards.straightdope.com/u/Tyrrell_McAllister)\ **Post date:** [April 12, 2009, 3:28pm UTC](https://boards.straightdope.com/t/name-of-this-probability-paradox/492573/61 "2009-04-12T15:28:12Z")
Great, now it looks like I was referring to my own post :D. ---
**Author:** ![Indistinguishable](https://avatars.discourse-cdn.com/v4/letter/i/90ced4/32.png) [@Indistinguishable](https://boards.straightdope.com/u/Indistinguishable)\ **Post date:** [April 12, 2009, 7:38pm UTC](https://boards.straightdope.com/t/name-of-this-probability-paradox/492573/62 "2009-04-12T19:38:51Z")
> [@Tyrrell\_McAllister](#): > > (Well, not before noting this: It follows from my view that, in the calendar-less case, she’s not able to assign a credence to the statement “It’s Monday” at all. If she uttered this statement, it would fail to refer to any particular day. Even though her utterance happens on a particular day, she has no way of specifying that day, so she can’t imbue her utterance with that meaning.) Interesting. So she wouldn’t even be able to imbue the statement “It’s currently the case that everyone outside is going around calling the day ‘Monday’ (even though I can’t access them)” with meaning, even though she _can_ imbue the statement “The coin flip came up heads (even though I can’t access any record of its results)” with meaning? ---
**Author:** ![Tyrrell\_McAllister](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tyrrell_mcallister/32/16772_2.png) [@Tyrrell\_McAllister](https://boards.straightdope.com/u/Tyrrell_McAllister)\ **Post date:** [April 12, 2009, 7:48pm UTC](https://boards.straightdope.com/t/name-of-this-probability-paradox/492573/63 "2009-04-12T19:48:55Z")
> [@Indistinguishable](#): > > Interesting. So she wouldn’t even be able to imbue the statement “It’s currently the case that everyone outside is going around calling the day ‘Monday’ (even though I can’t access them)” with meaning, even though she _can_ imbue the statement “The coin flip came up heads (even though I can’t access any record of its results)” with meaning? Yes. Since there was only one coin-flip, SB can indicate it uniquely, so she can meaningfully ask whether it came up heads. But she can’t meaningfully ask whether everyone outside currently thinks it’s Monday, because she can’t indicate the day on which the thinking that she is asking about is happening. That, at least, is my position. ---
**Author:** ![Indistinguishable](https://avatars.discourse-cdn.com/v4/letter/i/90ced4/32.png) [@Indistinguishable](https://boards.straightdope.com/u/Indistinguishable)\ **Post date:** [April 12, 2009, 8:03pm UTC](https://boards.straightdope.com/t/name-of-this-probability-paradox/492573/64 "2009-04-12T20:03:01Z")
Well… I imagine what you are saying is that SB knows there are two days in consideration, one where people outside say Monday and one where people outside say Tuesday, but she can’t manage to assign to these the labels “now” and “not now” in any fashion, because they’re totally symmetric to her; there’s no way to distinguish the one from the other. I am amenable to speaking this way. However, while doing so, I would feel compelled to also similarly argue that SB knows there are two histories in consideration, one where the coin came up heads and one where it came up tails, but she can’t manage to assign to these the labels “the actual history” and “an alternative history” in any fashion, because they’re totally symmetric to her; there’s no way to distinguish the one from the other. Why should we be able to say “there was only one past coin-flip [i.e., there is only one coin flip result in the ‘actual’ history]” if we cannot equally as well say “there is only one outside day-value [i.e., there is only one day-value for the ‘current’ outside]”? Seems to me we can accept both or reject both, but we oughtn’t treat one differently from the other. ---
**Author:** ![Tyrrell\_McAllister](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tyrrell_mcallister/32/16772_2.png) [@Tyrrell\_McAllister](https://boards.straightdope.com/u/Tyrrell_McAllister)\ **Post date:** [April 12, 2009, 8:11pm UTC](https://boards.straightdope.com/t/name-of-this-probability-paradox/492573/65 "2009-04-12T20:11:22Z")
I’m going to start a thread on the SB paradox in Great Debates. I think we’ve left the original topic of this thread behind :). ---
**Author:** ![Tyrrell\_McAllister](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tyrrell_mcallister/32/16772_2.png) [@Tyrrell\_McAllister](https://boards.straightdope.com/u/Tyrrell_McAllister)\ **Post date:** [April 12, 2009, 8:54pm UTC](https://boards.straightdope.com/t/name-of-this-probability-paradox/492573/66 "2009-04-12T20:54:34Z")
I’ve created a thread about the Sleeping Beauty paradox here: [http://boards.straightdope.com/sdmb/showthread.php?p=11031178#post11031178](http://boards.straightdope.com/sdmb/showthread.php?p=11031178#post11031178) **Indistinguishable** , I’ll reply to your question if you post it there. I’ll say now that my answer depends on the notion of “possible world” that you’re using. Kripkian modal logic semantics? Lewisian? Many-Worlds interpretation of QM? Multiverse? [Previous page](https://boards.straightdope.com/t/name-of-this-probability-paradox/492573.md?page=3)