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From: ethan@utastro.UUCP (Ethan Vishniac)
Newsgroups: net.bio,net.origins,net.sci
Subject: Re: The missing step -- self-reproducing organisms
Message-ID: <812@utastro.UUCP>
Date: Tue, 20-Nov-84 22:00:53 EST
Article-I.D.: utastro.812
Posted: Tue Nov 20 22:00:53 1984
Date-Received: Sat, 24-Nov-84 20:59:37 EST
References: gatech.10770 <3469@ecsvax.UUCP> <10810@gatech.UUCP> <1262@hao.UUCP>, <474@uwmacc.UUCP>
Organization: UTexas Astronomy Dept., Austin, Texas
Lines: 30

>>    I think the concept that everyone is trying to get at here is this:
>>
>>If an event has a probability of occuring that is greater than zero, and there
>>are an infinite number of attempts at it, then the probability that it will
>>eventually occur is indeed 1, no matter how small the probability that it will
>>happen on a given attempt. The only assumption needed here is that time
>>goes on forever (and I'm not going to debate that here, I take that as a given).

>This argument is an example of the gambler's fallacy:  if I lose
>*this* time, then it's more likely I'll win *next* time.  The outcome
>of event i does not affect the outcome of event j in any way, for
>independent events.  (If the events are not independent, then the
>above argument doesn't apply anyway.)

>The event could occur the first time; it might never occur.
>-- 
>Paul DuBois		{allegra,ihnp4,seismo}!uwvax!uwmacc!dubois

No it is not an example of the gambler's fallacy.  The assertion being
made is that if one has N cases and the probability of the desired outcome
is some small, but finite number, then as N goes to infinity the probability
that the desired outcome is obtained *in at least one of the cases* goes to 
unity. The probability that the desired outcome is obtained in any single 
case remains small.
                         
"I can't help it if my     Ethan Vishniac
    knee jerks"         {charm,ut-sally,ut-ngp,noao}!utastro!ethan
                           Department of Astronomy
                           University of Texas
                           Austin, Texas 78712