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From: kube@cogsci.berkeley.edu.UUCP
Newsgroups: sci.philosophy.tech
Subject: Re: YADO - Yet another defense of Ockham's razor.
Message-ID: <20367@ucbvax.BERKELEY.EDU>
Date: Sun, 30-Aug-87 17:25:55 EDT
Article-I.D.: ucbvax.20367
Posted: Sun Aug 30 17:25:55 1987
Date-Received: Sun, 30-Aug-87 23:56:26 EDT
References: <8851@ut-sally.UUCP>
Sender: usenet@ucbvax.BERKELEY.EDU
Reply-To: kube@cogsci.berkeley.edu.UUCP (Paul Kube)
Organization: University of California, Berkeley
Lines: 51
Keywords: Ockham Occam razor explanation
Summary: What the philosophy of science needs

In article <8851@ut-sally.UUCP> turpin@ut-sally.UUCP (Russell Turpin) writes:
>     Being one of the earlier posters who appealed to it as a
>philosophic criterion for comparing scientific theories, I now
>feel obliged to put forth my defense of Ockham's Razor. 

Thanks for taking the time to make such a thoughtful response.  I have
only a couple of further remarks.

>  o  The term "theory" refers to a set of statements. 

Sounds good to me.

>  o  I assume some noncontroversial method for identifying which
>     statements are testable by observation. 
>     (This is a very controversial assumption,
>     but one that is not the subject of this article.)

I agree that the observational/nonobservational distinction turns
out to be pretty bogus when you lean on it too hard but for present
purposes it seems fine.

>     The justification for this is not difficult. Scientific
>theories are not deductively derived. The only reason for putting
>any stock in them at all is their explanatory power.  A
>scientific theory is assumed true because of the observable
>statements it predicts (contains). In particular, the only reason
>for believing any statement y in Y that is not in D is because it
>helps explain D. But in the case above this is not true for the
>statements in Y that are not in X. They can all be dropped with
>no weakening of the explanatory power of the theory. 

This is an elegant way of putting your point, but I worry that it
might be *too* elegant.  In particular: You are saying that a
theoretical statement y in a theory Y cannot help to explain the truth
of an observation sentence if the observation sentence is a
consequence of Y - y.   But in the "intuitive" sense of `help explain',
this doesn't seem right; y can in practice be used to explain
observations even though y is `in principle' eliminable.

The problem is that `explanation' seems to be a partly psychological
concept.  It's natural to cash it out in terms of the consequence
relation as you have (I'm inclined to do it myself), but it's not
clear how much is given up with this abstraction.  (It might be no
problem here; I think maybe you need only confirmation, not the full concept
of explanation, to run your argument; and confirmation is probably more
closely tied to consequence.)

What the philosophy of science needs, and does not have, is a good
theory of explanation.

--Paul kube@berkeley.edu, ...!ucbvax!kube