[lit-ideas] Re: Is 'All men are mortal' unscientific?
- From: Robert Paul <rpaul@xxxxxxxx>
- To: lit-ideas@xxxxxxxxxxxxx
- Date: Sun, 16 Mar 2008 16:40:55 -0700
Quine does use use '(x)'
to mean 'for all (any) x…'
Stipulated by both parties.
My points, repeated here for those who just turned in are
(1) 'All men are mortal' cannot be put into the notation of first-order
predicate calculus thus: 'there is a time t such that x dies at x.'
Conceivably, one might work this around to mean 'There is an x, there is
a t, and x dies at t.'
There is, I'll now add, a further difficulty with the expression. 'There
is an x, there is a t, and x dies at t,' implies that where x is a
particular plant or animal, x dies at some specific time, namely, t.'
That such a form of fatalism (or determinism) should be attributed to
Quine (although I don't know his theological preferences) is to say the
least, odd. It is trivially true that if some creature is mortal it will
die at some time or other, we know not when. But the formulation we're
given is ambiguous as between 'there is some time, say, 3:00 am,' and
some unspecified time or other. The former view I've called fatalism.
From the natural language sentences, 'Every boy loves some girl,' and
'All roads somewhere,' one cannot infer that there is some girl, Alice,
who is loved by every boy, or that all roads lead to the same place,
namely Rome. It took Frege to show how such sentences could be
disambiguated in formal notation.
(2) The reason behind (1). When we want to speak of every man (or every
thing of a certain kind,' that we are doing so must expressed either
through the conventions of some natural language, or in the formalized
notation of logic. Donal seems clear as a bell about how to read '(x) if
Fx then Gx)' (if anything is F it is G), where an x enclosed in ordinary
parenthesis is the sign for universal generalization. Why he then
maintains both that 'All men are mortal' can be expressed formally with
no mention of 'men' and no indication that the putative formalization of
the original univiversal generalization is itself a universal
generalization leads to deeply metaphysical questions.
On the other hand, I've heard that Scope is the name of a mouthwash,
Robert Paul
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