Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!linus!decvax!ittvax!wxlvax!awex
From: awex@wxlvax.UUCP (Alan Wexelblat)
Newsgroups: net.religion
Subject: Truth in Philosophy of Science
Message-ID: <214@wxlvax.UUCP>
Date: Tue, 10-Jan-84 19:27:00 EST
Article-I.D.: wxlvax.214
Posted: Tue Jan 10 19:27:00 1984
Date-Received: Wed, 11-Jan-84 05:34:18 EST
References: mit-eddi.1137
Lines: 33

{Yes, I know this ought to go in net.philosophy, but y'all are debating 
 about what is true here, so I thought I'd post it here.}

There are two things to think about when talking about truth.  One is the
distinction between *a priori* truth and *a posteriori* truth.  Things
that are *a priori* true, are true "by definition."  Things that are 
*a posteriori* true are true in virtue of what we have discovered.

The second dimension is the distiction between *analytic* truth and 
*synthetic* truth.  Something is analytically true if it can be 
rigorously proven (within a given system, as Godel showed).  Something is
synthetically true if it is supported by an acceptable majority of the
experimental evidence.

Now, things like mathematics and logic are *a priori analytically* true.
For example, 2 + 2 = 4 is true by virtue of the menaings of the symbols
'2','4','+', and '='.  Similarly, True and False is False, by the rules 
of logic.

On the other hand, all of science is *a posteriori synthetically* true.
Which is to say that it's not possible to PROVE any scientific 
conclusion.  All we can say is that all evidence so far supports it.
Therefore, greg, it is incorrect to lump science and mathematics
together in talking about truth.

One interesting note is that geometry is the only thing that is 
*a posterioir analytically* true, in that it is ture by virtue of the
way that the world if, but we can still construct proofs about it.  This
is the case for both Euclidean and non-Euclidean geometries; the only
difference is what you assume the universe to be like. 

--Alan Wexelblat (the vanishing philosopher)
...decvax!ittvax!wxlvax!awex