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

[Shawn Barr]

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/
>
>
>
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