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From: pindor@gpu.utcc.utoronto.ca (Andrzej Pindor)
Subject: Re: rereRe: The end of god
Message-ID: <CyAuIG.Bot@gpu.utcc.utoronto.ca>
Organization: UTCC Public Access
References: <36vt2m$g6m@scapa.cs.ualberta.ca> <Cxzo7E.91v@gpu.utcc.utoronto.ca> <Harmon.776.000A2404@psyvax.psy.utexas.edu> <burt.783102882@aupair.cs.athabascau.ca>
Date: Wed, 26 Oct 1994 21:32:40 GMT
Lines: 45

In article <burt.783102882@aupair.cs.athabascau.ca>,
Burt Voorhees <burt@aupair.cs.athabascau.ca> wrote:
>>>>Your example just illustrates the Goedel theorem.  The point I was trying to
>>>>make was that to know something 'for sure' we also use mathematics, even
>>>>if applied to a system external to the one in which this something is true.
>>>>Short of divine inspiration, what we hold to be true in science is arrived a
>t
>>>>by logical reasoning at some level. We may propose various conjectures and
>>>>even have a deep, unfaltering belief that such a conjecture is true, it only
>>>>becomes a scientific truth if proven using logic. Penrose seems to suggest
>>>>that there are some scientific (mathematical) truths which logic cannot prov
>e.
>I disagree, there are many things which
>are accepted as scientific truths which
>have not been logically proved.  All that
>you can ever get using a logical proof is
>the statement that a certain hypothesis
>satisfies the coherence criterion for truth,
>so that all you can know is that _if_ your
>initial axioms are true, _then_ the
>hypothesis is also true.  Logic is used
>to insure that a hypothesis does not contradict
>the current theory within which it is stated.
>
>On the other hand, no empirical "law" is ever
>logically proved.  It is established by repeated
>regularities.  That is, via the correspondence
>criterion for truth.
>bv

You misunderstood me or my statement was not clear enough. You certainly are
right about "empirical laws". What we accept as scientific truths in say
physics, comes from applying logical reasoning to empirical results - it
certainly would be illogical to say that if something happened 100 times,
it will _always_ happen. So such "truths" are always tentative. Did you mean 
something else by "many things which we accept as scientific truths which have 
not been logically proved"?

Andrzej

-- 
Andrzej Pindor                        The foolish reject what they see and 
University of Toronto                 not what they think; the wise reject
Instructional and Research Computing  what they think and not what they see.
pindor@gpu.utcc.utoronto.ca                           Huang Po
