SV: Capacity of the brain

Bill Todd billtodd at foo.mv.com
Sat Nov 27 14:52:56 EST 1999


Matt Jones <jonesmat at ohsu.edu> wrote in message
news:81mnkr$j06$1 at fremont.ohsu.edu...
> In article <81jmfs$fv2$1 at pyrite.mv.net> Bill Todd, billtodd at foo.mv.com
> writes:
> >Am I the only one who believes that 'random' means that the probabilities
of
> >all possible outcomes are equal?  If that is the proper definition, then
> >'random' is a far stronger characterization than 'non-deterministic', and
> >some of the foregoing discussion points may have been flying past each
other
> >without contact.
> >
>
> Think of the classical example of something "random": the Gaussian
> distribution. This is definitely NOT a case of all probabilities being
> equal. There is a peak in the distribution at which the probability is
> higher than at other values. What you are thinking of is a "uniform"
> distribution, such as when you flip a fair coin or roll a fair die. Note
> that if you roll two fair die, and calculate the probabilities of their
> SUM, you no longer have a uniform distribution, but something closer to a
> Gaussian.

... which I would say makes the sum of a multi-die roll non-random, though
non-deterministic as well.  In fact, I might go so far as to say that even
the result of a one-die roll is not random, and amend my (unfortunately
mis-)stated understanding of 'random' to mean 'unpredictable in any way,
including probabilistically':  otherwise, one could state that virtually
every physical phenomenon exhibits random behavior, which is not
particularly useful.

So what I'm asking is whether there is indeed a well-accepted definition of
'random' in this context, and if so what it is.

- bill

>
> Cheers,
>
> Matt Jones






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