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From: carter@gatech.UUCP (Carter Bullard)
Newsgroups: net.bio,net.origins,net.sci
Subject: Re: The missing step -- self-reproducing organisms
Message-ID: <10810@gatech.UUCP>
Date: Thu, 15-Nov-84 16:18:00 EST
Article-I.D.: gatech.10810
Posted: Thu Nov 15 16:18:00 1984
Date-Received: Fri, 16-Nov-84 07:02:26 EST
References: gatech.10770 <3469@ecsvax.UUCP>
Organization: School of ICS, Georgia Institute of Technology, Atlanta
Lines: 60
Xref: gatech net.bio:119 net.origins:511 net.sci:208

> <>
> carter@gatech says:
> > Indeed, it is an extremely complex thing.  However, the probability of
> > complex living organisms evolving ( coming into existence ) is actually very
> > high, say 1, since it has occured, for whatever reason.
> 
  and Ted Emigh retorts:
> In the same manner, let me toss a coin.  As you can see, it is 'heads'.
> Does this mean that since heads has occurred the probability of
> obtaining heads is 'actually high, say 1'?  An event occurring does not
> alter the probability that it would have occurred--however it may
> alter our perception (estimation) of the probability that it will occur.
> 
  What I would like to say is that it is difficult to talk about the
  probability of a past event having occured.  If I toss a coin x number
  of times, the probability that a specific sequence will occur is a simple
  concept.  But if after obtaining a sequence, I then ask the question, what is
  the probability that that sequence of coin tosses did just now occur, I
  believe the only real answer is 1.  You are absolutely correct in saying
  that the calculation of the probability of a future event is not affected 
  by any subsequent occurence of the event( assuming a random process ). 

  But, I believe that statistics provides for a sensation of confidence over 
  events whose determinates are not completely known, a kind of blind but 
  very educated quess.  If one utilizes the appropriate approximation of 
  distributions or chooses the appropriate model, then the statistic can 
  give reasonable approximations for the confidence of a specific occurence.  
  But when one looks back in retrospect at an event that has already occured, 
  the temptations that "causality" allow spring to mind and suggest, " if 
  we had only known everything that was involved in the process, then possibly 
  we could have calculated that its occurence was indeed inevitable ."

  If you would rather suggest that statistics is involved with the analysis
  of potentiality, instead, then in the specific case of the current disscusion
  "living organisms and their evolution", I think that you would be hard pressed
  to suggest that any other possibility for either molecular or cellular 
  organization is available.  The biochemical and physiological basis for 
  "living organisms" is so consistent among all, and I mean all, the samplings
  that are available on this planet that it is very difficult to suggest that
  we represent one of a set of survivable random configurations.  Although
  the apparent level of complexity in the evolution of "living organisms" is
  quite high, there is no reason to suspect that on that path there were any
  other possible routes than the specific one that was taken.  And without
  the demonstrated occurence of other potential states,  the discussion of
  what the probability of any specific stage should be, is quite premature. 
  
  Let's not reduce the discussion of evolution to the scenario of a coin toss.
  
  The popular concept of genetics and evolution is extremely outdated, being 
  similar to the theories of people who had never dreamed of DNA and the 
  biochemical processes involved in self- replication, and their attitudes 
  were that randomness played a great role in the construction and direction 
  of evolutionary development.  These ideas I feel give randomness too high of
  a hand in the game.  I would rather think it was much more deterministic 
  than they would have had us believe.
-- 
Carter Bullard
ICS, Georgia Institute of Technology, Atlanta GA 30332
CSNet:Carter @ Gatech	ARPA:Carter.Gatech @ CSNet-relay.arpa
uucp:...!{akgua,allegra,amd,ihnp4,hplabs,seismo,ut-ngp}!gatech!carter