[FRIAM] What does it mean to say that it will probably rain tomorrow?

[Carl Tollander]

Well, I think the weather forecast does not particularly care about your
particular location.   It cares about what area you are in where they can
make statements.   So, the statement that it may rain in Santa Fe with a
50% probability either means that in some larger region of which your
specific location is a part that it WILL rain all of the time in the time
period over 50% of the area.   Or that it may rain half the time over all
of the area.  Or that, given that you are in the area, it's 50% probable
that it will rain upon you given that it will definitely rain in the area
somewhere.  Or something else.   Not quite the same things.

C




On Thu, Feb 16, 2017 at 11:23 AM, Shawn Barr <sbarr2 at gmail.com> wrote:

> Hi Nick,
>
> In an effort to diaspeirein(?), let me offer the following:
>
> According to the axioms of probability (maybe you heard this already on
> Friday), saying that something has a probability of 1 (or .5) doesn't mean
> that it will happen (or happen half of the time); it just means that the
> probability of something not happening is 0 (or .5).
>
> In terms of a weather forecast, (which I assume might be what you were
> getting at,) saying that there is a 50 percent chance of rain tomorrow
> could mean something like, conditioned on the present, rain happened 50
> percent of the time in the past.  Assume that the future and past are
> conditionally independent given the present and expect a 50 percent chance
> of rain tomorrow.  Or maybe that's not not a not (?) sensible expectation?
>
>
> Best,
> Shawn
>
> On Sat, Feb 11, 2017 at 9:49 AM, Nick Thompson <nickthompson at earthlink.net
> > wrote:
>
>> Dear all,
>>
>>
>>
>> We had an interesting conversation in the Friday meeting of the local
>> congregation concerning the question, “What does it actually mean to say
>> that there is a 50 percent chance of rain in Santa Fe tomorrow?”  Exactly
>> what operations would you have to go through to discover if that claim was
>> appropriate or not?
>>
>>
>>
>> I took the position that whether it actually rained tomorrow had very
>> little to do with validating the claim.
>>
>>
>>
>> I am wondering what those of you in the diaspora thought.
>>
>>
>>
>> Nick
>>
>>
>>
>> Nicholas S. Thompson
>>
>> Emeritus Professor of Psychology and Biology
>>
>> Clark University
>>
>> http://home.earthlink.net/~nickthompson/naturaldesigns/
>>
>>
>>
>> ============================================================
>> FRIAM Applied Complexity Group listserv
>> Meets Fridays 9a-11:30 at cafe at St. John's College
>> to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com
>> FRIAM-COMIC http://friam-comic.blogspot.com/ by Dr. Strangelove
>>
>
>
> ============================================================
> FRIAM Applied Complexity Group listserv
> Meets Fridays 9a-11:30 at cafe at St. John's College
> to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com
> FRIAM-COMIC http://friam-comic.blogspot.com/ by Dr. Strangelove
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://redfish.com/pipermail/friam_redfish.com/attachments/20170216/76fe59e2/attachment-0002.html>