From: "Hill, David" 
Date: Wed Feb 20, 2002 4:31pm
Subject: RE: [evol-psych] "ought" can be plausibly derived from an "is"?

Irwin Silverman wrote:

        I am not a professional philosopher so forgive me if this is
naive, but I see your example above as an apt demonstration of the
dichotomy between "is" and "ought"

        Your knife "is" dull - that is a fact.  But whether you "ought"
to sharpen it or not is a value judgement, depending potentially on many
things - e.g. how you plan to use it (are you a serial killer?) - whether
you have to forego more critical purchases to buy a knife sharpener, etc.

        I don't mean to offend, but these protracted discussions of the
obvious remind me of Alexander Pope - "A man of business may talk of
philosophy; a man who has none may practice it."


Reply:  This simply ignores the concession plainly present in my posting.  That
the one statement does not entail the other as a logically valid consequence,
sans supporting premises, is obvious.  In any case, the relevant point is that
statements about better and worse behavior may follow from premises available
to us all, together with results that might possibly be obtained from EP.  By
the way, why do people typically say (without argument) that "ought" claims are
value judgments?  To say that X ought to do Y is not, prima facie, to make any
value judgment at all.  It is not, for example, to say that doing Y is better
than not doing Y, or that it would be good for X to do Y.  Indeed, it is
perfectly consistent -- though odd -- to say "Y is a very bad thing and I
rather hope you won't do it, but nonetheless you have an obligation  to do it
and ought to do it."  Between "ought" claims and ordinary value judgments there
is at least as much of a logical gap as any between is's and oughts.

David Hill writes:

There is an interesting assumption that runs through this and similar arguments
for Hume's semantic dualism.  The assumption is that if we can't get
entailments from descriptions, what good is the evidence anyway?  To which one
ought to respond that descriptions are not typically more certain than
normative claims, and thus nothing is to be gained by restricting one's
evidence set to claims that are rigidly descriptive.  An outstanding moral
philosopher once put it this way. "If these lovers of tidy logical dichotomies
don't want to call the derivation "implication," then I give them the word.
Call it "shimplication."  Call it whatever you wish.  The question is whether
the sustaining argument is sound, not whether it fits neatly into Hume's
impoverished ontology."  If someone could derive significant moral conclusions
from factual descriptions, plus an appropriate functional analysis of a
Darwinian sort, plus a few unchallenged axioms, that would be worth doing,
however you characterize the several sorts of premises involved.