From: zeleny@husc10.harvard.edu (Michael Zeleny)
Newsgroups: sci.philosophy.meta
Subject: Re: Extensionalism (was re: Russell's Paradox)
Date: 6 Nov 92 19:23:05 GMT
Article-I.D.: husc3.1992Nov6.142307.17166
Organization: The Phallogocentric Cabal

In article <1992Nov2.012719.19544@guinness.idbsu.edu> 
holmes@garnet.idbsu.edu (Randall Holmes) writes:

>In article <1992Oct30.164628.16941@husc3.harvard.edu>
>zeleny@husc10.harvard.edu (Michael Zeleny) writes:

>>In article <1992Oct30.174335.19102@guinness.idbsu.edu>
>>holmes@opal.idbsu.edu (Randall Holmes) writes:

>>>In article <1992Oct29.212223.20343@tamsun.tamu.edu>
>>>cmenzel@tamsun.tamu.edu (Chris Menzel) writes:

>>>>In article <1992Oct26.170430.14372@guinness.idbsu.edu>
>>>>holmes@garnet.idbsu.edu (Randall Holmes) writes:

RH:
>>>>>_Contra_ Harter (miscellaneous quibbles):
>>>>>
>>>>>The Good Russell may have admitted the possibility of "intensions",
>>>>>but the Exalted Quine has liberated us from the influence of those
>>>>>"creatures of darkness".  Extensions are adequate for all admissable
>>>>>purposes.

CM:
>>>>Really, Randall?!  Could you then please give me an extensional
>>>>analysis of the sentences in the following arguments that explains why
>>>>the first is valid but the second is not:
>>>>
>>>>1)  John believes there are spies.
>>>>    Mary believes whatever John does.
>>>>    Therefore, Mary believes there are spies.
>>>>
>>>>2)  John believes that 2=3=5.
>>>>    Necessarily, 2+3=5 iff first-order logic is undecidable.
>>>>    Therefore, John believes that first-order logic is undecidable.
>>>>
>>>>Or is a purpose admissible just in case it is amenable to
>>>>extensionalist analysis?

>>>>
>>>>  Chris Menzel
>>>>  Philosophy Department
>>>>  Texas A&M University

MZ:
>>Good call, Chris.  You might want to take a look at my anti-Quinean
>>diatribe elsewhere in this group for different objections to Randall's
>>extensionalism along similar lines.

RH:
>>>Belief is not closed under inference, as we all know well from
>>>personal experience.  I imagine that belief is amenable to extensional
>>>analysis, like everything else; but it admits no simple analysis (in
>>>particular, it is not a nice modal operator).

MZ:
>>Randall, this is at least the second time you have said that, adducing no
>>better argument than the claim of your febrile imagination.  For a
>>perfectly well-defined example of deductively closed, normatively construed
>>notion of belief, check out Isaac Levi's distinction between doxastic
>>performance and commitment.

RH:
>Your beliefs are not deductively closed, and neither are mine.

Not in a common psychological sense; however once you construe belief
forensically, you have to impose a deontic closure thereupon; and such
deontic closure surely subsumes the deductive variety.  (In particular,
both arguments cited by Chris are valid when so construed.)  Of course,
the forensic notion of belief is perfectly legitimate and useful,
provided that one does not interpret it as open to awareness.  In
particular, it is extensionally equivalent to a metaphysical notion of
ideal epistemic modality, which suffices to resolve the problems I
attribute to extensionalism below.

MZ:
>>To articulate some of the propositions I have insinuated earlier, without
>>intensionality there can be no explanatoty theory of reference (a.k.a.
>>denotation); on the adoption of the Frege-G\"odel-Church argument, as done
>>e.g. in Tarskian model theory, that truth-values are denoted by declarative
>>sentences, there can be no explanatory theory of truth, either.

RH:
>This is indeed the kind of theory to which I adhere.  What do you mean
>by an "explanatory" theory?  By the way, I _do_ allow intensional
>objects, but they are not primary:  equivalence classes of terms and
>sentences under suitable relations can be used for this purpose.

An explanatory theory strives to discover the essence of its subject and
to characterize the nature of its functioning, rather than remain
content with describing the necessary and sufficient conditions for
recognizing the same.  In fact, as I suggest below, your extensionalism
will not allow you to accomplish the latter task, either.

MZ:
>>								  Worse, no
>>additional theoretical constraints will result in genuinely structural, or
>>analytical theory of the same, as is witnessed already by the well-known
>>phenomenon of Boolean duality, -- nothing in your extensional theoretical
>>framework can prevent me from permuting your truth-values by a
>_fiat_!

RH:
>Feel free to permute the truth-values, if you like.  They are
>symmetrical, after all.

Well then, what is it that distinguishes truth from falsehood?

MZ:
>>Finally, to resort to a crude _ad hominem_ argument, your self-professed
>>realism is philosophically incompatible with your extensionalism.

RH:
>Demonstration?

I attempted to elicit the demonstration of this incompatibility by
probing your claim that you could give an extensional account of
intensional notions; alas, you shied away from supporting it with any
sort of argument.  At this point, I am unable to go beyond suggesting
that you take a look at the organic relationship obtaining between
Quine's antirealist epistemology, and his extensional ontology.  A
good place to start is his _Word and Object_; some of the positions
already implicit there are fully articulated in the work of Rorty.
Briefly, unless you can find a way to countenance necessary truths,
you will never be able to give more than a conventionalist account of
truth _simpliciter_.  In a nutshell, this is what makes Quineanism so
inadequate as a conservative foundation of mathematics.

MZ:
>>Kindly cease and desist from promulgating this ignoble pragmatist claptrap.

RH:
>I am certainly not a pragmatist.

Here is a nice example of the Levi distinction between doxastic
performance and commitment.  If the line of argumentation I suggested
above is correct, then your espousal of extensionalism commits you to
a pragmatist metaphysics; however if I am to take your disclaimer at
face value, your doxastic performance is yet to catch up to itc
commitments.  So what will it be?

>-- 
>The opinions expressed		|     --Sincerely,
>above are not the "official"	|     M. Randall Holmes
>opinions of any person		|     Math. Dept., Boise State Univ.
>or institution.			|     holmes@opal.idbsu.edu

cordially,
mikhail zeleny@husc.harvard.edu
" -- I shall speak bluntly, because life is short."
Newsgroups: sci.philosophy.meta