From: emc@doe.carleton.ca (Eli Chiprout)
Subject: Re: On God and Science
Organization: Dept. of Electronics, Carleton University
Date: Mon, 21 Dec 1992 14:39:34 GMT

In <20DEC199214091069@skyblu.ccit.arizona.edu> lippard@skyblu.ccit.arizona.edu (James J. Lippard) writes:

>In article <1992Dec20.003729.10684@aurora.com>, isaak@aurora.com (Mark Isaak) writes...
>>I, too, once marveled at the unlikelihood of everything in the
>>universe coming together in such a way to create me.  Such an occurrance
>>seemed wildly improbable.  Then I realized that, had all circumstances
>>not been as they were, I wouldn't be around to marvel, so questions of
>>probability are meaningless.  The probability of my existence, given that
>>I exist, is exactly one, no matter what my theological assumption

>This seems like a bad argument, to me.  Suppose I'm put in front of a firing
>squad of fifteen men.  They all fire, but I don't die.  I continue to
>exist.  By an argument analogous to what you've given, I shouldn't marvel
>at my own continued existence or wonder how it happened--the probability
>was one.  But if, in fact, all fifteen men *missed* me, there is an unusual
>fact there that requires some sort of explanation.  The fact that if they
>hadn't missed me, then I wouldn't be there to puzzle over my existence, does
>*not* explain what is curious in this situation.  Likewise, the fact of
>life's existence requires some sort of explanation other than the supposed
>"explanation" offered by the anthropic principle.

You are using analogy in your reasonin, and analogies are interesting for
pedagogical purposes only.  Here is where the analogy breaks down.
In the case of a trained riffleman firing, I can make an educated guess as
to the chance of his hitting the target given the size of my body, the
weather conditions, his distance, etc.  If that chance is high by my 
reckoning and -- more importantly -- my experience, both personal and second
hand through reporting, and he misses, I might be surprised.  If fifteen men
miss, I will surely require an explanation.
When you are discussing the universe, our personal experience, and the
experience of our peers are useless.  What are the chances that I will come
into being given the universe at the big bang?  Well, how can I answer that
if I do not know what the universe is besides my own miniscule part of it,
or what the chances of the counter event, i.e. my not existing, are.  What I
judge to be an "unusual" event, is a valueless judgement, because I have not
observed very many "usual" events, i.e. universes that unfold with no life
ever arising.
The anthropic principle is very clever in this respect, although certainly not 
a proof of anything.  It simply says, that there could easily be many worlds,
before us, after us, besides us, that do not contain life.  Since we could
not be part of those worlds, we are amazed at our unique existence.  In fact,
if there was exactly one big bang and "gib gnab" (or big crunch) before us,
(with no life) our chance would be one in two for existing in a world.  If
there were 100? or 100^100?  The anthropic principle says that given the 
possible infinite(very large) nature of the universe, our chance for existence 
could be small, but when it happens, we will only be able to observe the 
conditions that bring about life, not the (possibly much, much more probable)
conditions that will not allow life to exist.

Probability can be tricky in this respect.  If I only observe my universe,
and by observing it, I verify that I am alive, then the chances for my existence 
given my existence (i.e. <A|A> the chances of A given A) are 100%.  However, the
probability of my existence given all possible conditions/universes/worlds
is meaningless, since according the the anthropic principle, I will never
be able to observe/count those other worlds (much less calculate the 
possibility of their existence), in sharp contrast to the 15 riflemen.


>Jim Lippard              Lippard@CCIT.ARIZONA.EDU
>Dept. of Philosophy      Lippard@ARIZVMS.BITNET
>University of Arizona
>Tucson, AZ 85721
--
Eli Chiprout                 
Dept. of Electronics, 
Carleton University, Canada
emc@doe.carleton.ca