HDTenEightyP/NetNews huggingface dataset:
From: pratt@Sunburn.Stanford.EDU (Vaughan R. Pratt)
Subject: Re: Multiple Truth Values
Organization: Computer Science Department,  Stanford University.
Date: Tue, 12 Jan 1993 09:44:23 GMT

In article <1993Jan10.151351.19163@husc3.harvard.edu> zeleny@husc10.harvard.edu (Mikhail Zeleny) writes:
>
>To recapitulate the substance of past battles, Alfred Tarski, in his
>article "On Extensions of Incomplete Systems of Sentential Calculus",
>appeals to what has come to be known as Lindenbaum's Lemma, proving that
>there exists but one (absolutely) complete and consistent extension of
>incomplete sentential calculi, which contain as theorems certain
>formulae (namely, CpCqp, CpCCpqq, and CCqrCCpqCpr), expressing naturally
>evident properties of material implication.

It is worth mentioning that CpCCpqq (i.e. p->((p->q)->q)) is derivable
from the other two (that is, from p->(q->p) (= K) and
(q->r) -> ((p->q)->(p->r))) (= S) by modus ponens, mainly via the same
derivation by which the lambda calculus combinator C (converse, Cfxy
reduces to fyx) is derived from the combinators K and S by
application.  This yields (p->(q->r)) -> (q->(p->r)), now substitute
q->r for p and the rest is clear.  K and S as propositions constitute a
complete axiomatization of the implicational fragment of intuitionistic
logic.  Peirce's axiom ((p->q)->p)->p supplies an example of an
implicational proposition that is in the classical theory but not the
intuitionistic.
-- 
Vaughan Pratt			There's safety in large condition numbers.
From: arodgers@dcs.qmw.ac.uk (Angus H Rodgers)
Newsgroups: sci.logic
Subject: Re: Multiple Truth Values
Date: 11 Jan 93 19:52:45 GMT
Organization: Computer Science Dept, QMW, University of London

In <1993Jan10.191221.19172@husc3.harvard.edu>
zeleny@husc10.harvard.edu (Mikhail Zeleny) writes:

>/zeleny/h:=:j

>Recommended for insertion in your global KILL file.

My newsreader, nzrn, has this as the default. :-) :-)
--
Gus Rodgers,  Dept. of Computer Science, | Cinema's worst romantic dialogue? --
Queen Mary & Westfield College, Mile End | "Mechagodzilla's brain is  installed
Road, London, England.   +44 71 975 5241 | in my stomach!" "I don't care if you
E-mail (JANET):   arodgers@dcs.qmw.ac.uk | are a cyborg  --  I still love you!"
Newsgroups: sci.logic
From: pratt@Sunburn.Stanford.EDU (Vaughan R. Pratt)
Subject: Re: Multiple Truth Values
Organization: Computer Science Department,  Stanford University.
Date: Tue, 12 Jan 1993 08:39:55 GMT

In article <1993Jan11.194737.11729@dcs.qmw.ac.uk> arodgers@dcs.qmw.ac.uk (Angus H Rodgers) writes:
>In <1993Jan10.005215.13278@CSD-NewsHost.Stanford.EDU>
>pratt@Sunburn.Stanford.EDU (Vaughan R. Pratt) writes:
>>[...] double negation
>>served to retract a Heyting algebra onto a Boolean subalgebra of it
>
>Is this by any chance related to the construction of the regular open
>algebra of a topological space?

I haven't heard of that construction.  The retraction is the model
theoretic equivalent (i.e. the effect on the models) of the proof
theoretic statement that Boolean algebras can be axiomatized by adding
~~x = x to an axiomatization of Heyting algebras.  Any two distinct
elements x and ~~x of a given Heyting algebra are forced into
coincidence by this additional requirement.  The effect is to retract
that Heyting algebra (model of intuitionistic logic) H onto the largest
Boolean algebra (model of classical logic) embedded in H.

The result of the identification is to reduce the variety of truth
values in one's logic.  In intuitionistic logic not not x is in general
a weaker statement than x.  (It even *sounds* weaker, one respect in
which natural language seems to be intuitionistic rather than
classical.  This furnishes some evidence against two-valued logic,
necessarily Boolean, as the logic of natural language.)  That is, x
implies not not x but not necessarily the converse.  So if you
truthfully 'fess right up with "I broke the vase" then it cannot be
that you did not break the vase.  But if you say "I didn't not break
the vase" then while this tips us off to some degree of culpability on
your part it does not permit us to infer intuitionistically that you
actually broke the vase.

The passage from intuitionistic to classical logic erases this
distinction.

A common misconception is that eschewing the axiom ~~x = x deprives us
of part of mathematics.  As Goedel showed, every classically valid
theorem of mathematics has its intuitionistic counterpart, differing at
most in having a few double negatives sprinkled through it.  I like to
read "not not" as "surely."  All that adding ~~x=x to logic does to
mathematics then is to erase all instances of "surely" from theorems.
That is, the nuance expressed by the difference between the truth of
"x" and that of "not not x" is simply suppressed by Boolean logic,
which with only two truth values cannot "hear" the difference.
-- 
Vaughan Pratt			There's safety in large condition numbers.
From: arodgers@dcs.qmw.ac.uk (Angus H Rodgers)
Newsgroups: sci.logic
Subject: Re: Multiple Truth Values
Date: 12 Jan 93 22:43:50 GMT
Organization: Computer Science Dept, QMW, University of London

Are there only two truth values, or aren't there?

(And if it's false that there aren't only two, are there only two?)
--
Gus Rodgers,  Dept. of Computer Science, |
Queen Mary & Westfield College, Mile End |                       This .signatur
Road, London, England.   +44 71 975 5241 |                       British Rail a
E-mail (JANET):   arodgers@dcs.qmw.ac.uk |                       Normal service
From: rags@triples.math.mcgill.ca (Robert A. G. Seely)
Newsgroups: sci.logic
Subject: Re: Multiple Truth Values
Date: 10 Jan 93 22:57:39 GMT
Organization: /etc/organization

In article <1993Jan10.151351.19163@husc3.harvard.edu> zeleny@husc10.harvard.edu (Mikhail Zeleny) writes:
> ... long quote deleted ...

Just a software request - I couldn't find this via "man trn" :
Is there any way to add to one's "kill" file posts classified by author
rather than by subject?  It is becoming clear to me that this might be
useful.

- rags
From: fsp@thp.uni-koeln.de (Falko Spiller)
Newsgroups: sci.logic
Subject: Re: Doctrines of Maybe: 7 truth values
Date: 11 Jan 93 19:04:51
Organization: Institute of Theoretical Physics, University of Cologne, F. R.
	Germany
	<1993Jan11.100803.6802@cs.rug.nl>
NNTP-Posting-Host: sun7.thp.uni-koeln.de
In-reply-to: peterb@cs.rug.nl's message of Mon, 11 Jan 1993 10:08:03 GMT

an example:
in math we use really 4 truth values:
1.true (a proof is given)
2.false (a disproof is given)
3.independent (a proof of independence is given, eg.Cantor hypothesis)
  (ie. true xor false, ad libitum , if you want to say so)
4.unknown (else, eg. Riemann hypothesis)

and this will ever be the case if we have a incomplete logic without
entscheidungsverfahren. these four truth values are not new but always
used in mathematics. 

a good 1993.       falko spiller
--
Falko Spiller  fsp@thp.uni-koeln.de
Uni-Koeln,Inst.f.Theo.Physik
Newsgroups: sci.logic
From: pratt@Sunburn.Stanford.EDU (Vaughan R. Pratt)
Subject: Re: Multiple Truth Values
Organization: Computer Science Department,  Stanford University.
Date: Wed, 13 Jan 1993 05:17:10 GMT

In article <1993Jan12.224350.10516@dcs.qmw.ac.uk> arodgers@dcs.qmw.ac.uk (Angus H Rodgers) writes:
>Are there only two truth values, or aren't there?

Depends on who you ask.

>(And if it's false that there aren't only two, are there only two?)

Are you asking me or Zeleny?
-- 
Vaughan Pratt			There's safety in large condition numbers.
From: zeleny@husc10.harvard.edu (Mikhail Zeleny)
Newsgroups: sci.logic
Subject: Re: Multiple Truth Values
Date: 11 Jan 93 00:12:20 GMT
Article-I.D.: husc3.1993Jan10.191221.19172
 <1993Jan10.151351.19163@husc3.harvard.edu> <1993Jan10.225739.18143@sifon.cc.mcgill.ca>
Organization: The Phallogocentric Cabal

In article <1993Jan10.225739.18143@sifon.cc.mcgill.ca>
rags@triples.math.mcgill.ca (Robert A. G. Seely) writes:

>In article <1993Jan10.151351.19163@husc3.harvard.edu>
>zeleny@husc10.harvard.edu (Mikhail Zeleny) writes:

>> ... long quote deleted ...

>Just a software request - I couldn't find this via "man trn" :
>Is there any way to add to one's "kill" file posts classified by author
>rather than by subject?  It is becoming clear to me that this might be
>useful.

/zeleny/h:=:j

Recommended for insertion in your global KILL file.

>- rags

cordially,
mikhail zeleny@husc.harvard.edu
"Le cul des femmes est monotone comme l'esprit des hommes."
From: martinc@hatteras.cs.unc.edu (Charles R. Martin)
Newsgroups: sci.logic
Subject: Re: Multiple Truth Values
Date: 12 Jan 93 19:30:36
Organization: UNC Department of Computer Science
NNTP-Posting-Host: hatteras.cs.unc.edu
In-reply-to: arodgers@dcs.qmw.ac.uk's message of 12 Jan 93 22:43:50 GMT

In article <1993Jan12.224350.10516@dcs.qmw.ac.uk> arodgers@dcs.qmw.ac.uk (Angus H Rodgers) writes:

   Are there only two truth values, or aren't there?

Maybe yes, maybe no.
--
		Charles R. Martin/(Charlie)/martinc@cs.unc.edu
     Dept. of Computer Science/CB #3175 UNC-CH/Chapel Hill, NC 27599-3175
	    3611 University Dr #13M/Durham, NC 27707/(919) 419 1754
     "Oh God, please help me be civil in tongue, pure in thought, and able
      to resist the temptation to laugh uncontrollably.  Amen." -- Rob T
Newsgroups: sci.logic
From: pratt@Sunburn.Stanford.EDU (Vaughan R. Pratt)
Subject: Re: Multiple Truth Values
Organization: Computer Science Department,  Stanford University.
Date: Mon, 11 Jan 1993 20:03:15 GMT

In article <1993Jan10.151351.19163@husc3.harvard.edu> zeleny@husc10.harvard.edu (Mikhail Zeleny) writes:
>
>However, none of the above is to be taken as in any way impugning the
>incontrovertible fact that there are only two truth values

The other kind would be the controvertible fact, I take it.
-- 
Vaughan Pratt				There's safety in certain numbers.
Newsgroups: sci.logic
From: sunthej@alleg.edu (Jake Blues)
Subject: First Text
Reply-To: sunthej@alleg.edu
Organization: Allegheny College
Date: Tue, 12 Jan 1993 19:09:18 GMT



	I am looking for a good first text on logic for a one semester (15  
week) independent study.  As I have not found any FAQ for this group, so I  
was wondering if someone could make any recommendations.  It might be  
important to mention that It should be adequate to serve as a grounding  
for further mathematical and philosophical study into logic.

						Thank you in advance,
							Jake
From: turpin@cs.utexas.edu (Russell Turpin)
Newsgroups: sci.logic,sci.philosophy.tech
Subject: Re: Expression
Date: 6 Jan 1993 11:38:55 -0600
Organization: CS Dept, University of Texas at Austin
NNTP-Posting-Host: im4u.cs.utexas.edu

-*-----
In article <29144@optima.cs.arizona.edu> gudeman@cs.arizona.edu (David Gudeman) writes:
> ... Also, people engage in speech or other apparently
> communicative behaviors (rolling the eyes, shrugging, 
> etc.) with no intention to communicate. ...

You have convinced me.

> The only way to distinguish communication from other behaviors
> is by the intention of the one engaging in the behavior. ...

Sorry, I cannot be convinced and then unconvinced in so short
a space.

Russell
Newsgroups: sci.logic,sci.math,comp.ai,comp.ai.philosophy,comp.theory
From: torkel@sics.se (Torkel Franzen)
Newsgroups: sci.logic
Subject: Re: Multiple Truth Values
Date: 12 Jan 93 10:07:52 GMT
	<1993Jan10.005215.13278@CSD-NewsHost.Stanford.EDU>
	<1993Jan11.194737.11729@dcs.qmw.ac.uk>
	<1993Jan12.083955.19685@CSD-NewsHost.Stanford.EDU>
Organization: Swedish Institute of Computer Science, Kista

In article <1993Jan12.083955.19685@CSD-NewsHost.Stanford.EDU> pratt@Sunburn.
Stanford.EDU (Vaughan R. Pratt) writes:

   >So if you
   >truthfully 'fess right up with "I broke the vase" then it cannot be
   >that you did not break the vase.  But if you say "I didn't not break
   >the vase" then while this tips us off to some degree of culpability on
   >your part it does not permit us to infer intuitionistically that you
   >actually broke the vase.

  In your terminology then, a confession on your part in the form
"surely I broke the vase" must not be taken to mean that you did break
the vase, although an indignant denial in the form "surely I did not
break the vase" or "I did not surely break the vase" implies that you
did not break the vase. If you say "surely, if I broke the vase I must
have smashed the window" and later admit that you broke the vase, we
must be careful not to claim that you stand convicted on your own
evidence of having smashed the window, but only of having surely
smashed the window. I think this whole thing is a very shrewd move on
your part in that it practically guarantees that whatever misdemeanors
you may commit in the future, you will be able to confuse your
interrogators to the point where they prefer to drop all charges.
Presuming, of course, that your lawyer can convince the court that
this person, being an Intuitionist, must be interrogated in his own
language.
Newsgroups: sci.logic,sci.math,comp.ai,comp.ai.philosophy,comp.theory
From: hbe@sonia.math.ucla.edu (H. Enderton)
Subject: Joining ASL
Organization: UCLA Mathematics Department
Date: Mon, 4 Jan 93 17:16:55 GMT

                   Membership information for the

                   ASSOCIATION FOR SYMBOLIC LOGIC

The Association for Symbolic Logic is an international nonprofit
organization founded in 1936 for the promotion of research and critical
studies in symbolic logic.  Membership is open to anyone interested in
its work, e.g. the readers of this newsgroup.  Members receive The
Journal of Symbolic Logic, a quarterly journal containing research
articles, expository articles, abstracts, and reviews.  Members also
receive the Newsletter, and can obtain discounts on the Perspectives
in Mathematical Logic books from Springer and the Godel volumes from
Oxford.

Dues for individuals are $44 per year, or $22 per year for students.
Membership is based on the calendar year; you may join now for 1992
and receive all the 1993 issues of the Journal (volume 58).

How to join by e-mail:  For this you will need Mastercard or Visa.
Send mail to

               asl@symcom.math.uiuc.edu

giving all of the following information.
1.  Name and address
2.  Type of card (Mastercard or Visa)
3.  Number on card    [Do not post your credit card number to the net!]
4.  Expiration date of card
5.  If you are a student, then evidence of student status is requested.
You can have a faculty member send a supporting message on his or her
own log-in.  Or you can send a photocopy of your student ID by postal
mail.

How to join by postal service:  For this you need either a check or
postal money order in U.S. dollars, or a credit card as above.  Send
the information (including your e-mail address, if any) together with
dues payment to the following address.

    Association for Symbolic Logic
    Department of Mathematics
    University of Illinois
    1409 West Green Street
    Urbana, IL 61801, USA

[Questions or complaints can be directed to the poster,
H. B. Enderton (hbe@math.ucla.edu), ASL membership committee.]
From: zeleny@husc10.harvard.edu (Mikhail Zeleny)
Newsgroups: sci.logic
Subject: Re: Multiple Truth Values
Date: 12 Jan 93 01:34:39 GMT
 <1993Jan10.151351.19163@husc3.harvard.edu> <1993Jan11.200315.7771@CSD-NewsHost.Stanford.EDU>
Organization: The Phallogocentric Cabal

In article <1993Jan11.200315.7771@CSD-NewsHost.Stanford.EDU>
pratt@Sunburn.Stanford.EDU (Vaughan R. Pratt) writes:

>In article <1993Jan10.151351.19163@husc3.harvard.edu>
>zeleny@husc10.harvard.edu (Mikhail Zeleny) writes:

>>However, none of the above is to be taken as in any way impugning the
>>incontrovertible fact that there are only two truth values

>The other kind would be the controvertible fact, I take it.

The adjective you are fishing for is "alleged".  I highly recommend it
for your next revisionist excursus on the history of logic.

>-- 
>Vaughan Pratt				There's safety in certain numbers.

 
cordially,
mikhail zeleny@husc.harvard.edu
"Nothing can be said truly of what does not exist."
Newsgroups: sci.logic
From: jamie@cs.sfu.ca (Jamie Andrews)
Subject: Multiple Truth Values
Organization: CSS, Simon Fraser University, Burnaby, B.C., Canada
Date: Fri, 8 Jan 1993 22:39:15 GMT

(Note cross-posting; also posted to soc.religion.eastern
 and soc.religion.bahai, which are moderated.)

     There has been some talk lately on sci.logic about cultures
and religions which have multiple truth values.  In particular,
it has been asserted that the Jains have (or had at some time)
seven truth values.

     In traditional Western thought, in contrast, there are just
two truth values (true and false).  Lately, logic researchers
have been playing around with the "undefined" truth value and
with a "both true and false" truth value.  I think we sci.logic
people would be interested in hearing about philosophically- or
religiously-motivated theories of truth.

     Anyone care to expound on the Jainian or other conception
of truth values?  I would be especially interested in hearing
what exactly these truth values are supposed to signify, and in
examples of statements with each of the truth values.  Any
reference books you can suggest?

thanks
--Jamie.
  jamie@cs.sfu.ca
"The Tao's net encompasses the whole universe."  - tao te ching
Newsgroups: sci.logic
From: pratt@Sunburn.Stanford.EDU (Vaughan R. Pratt)
Subject: Re: Multiple Truth Values
Organization: Computer Science Department,  Stanford University.
Date: Tue, 12 Jan 1993 07:31:10 GMT

In article <1993Jan12.010844.14146@galois.mit.edu> jbaez@riesz.mit.edu (John C. Baez) writes:
>In article <1993Jan10.005215.13278@CSD-NewsHost.Stanford.EDU> pratt@Sunburn.Stanford.EDU (Vaughan R. Pratt) writes:
>>Let me strongly recommend Birkhoff's Lattice Theory [...]
>
>Also, if you are feeling adventurous and willing to drop distributivity,
 ^^^^
>you might check out the extensive literature on quantum logics.

For this let me strongly recommend Birkhoff's Lattice Theory.  Sections
II.14 (pp.52-54), XI.11 (pp.273-276), and XII.6 (pp.284-286) together
pack more useful information about quantum logic into 8 pages than any
other single reference I know.
-- 
Vaughan Pratt			There's safety in large condition numbers.
From: arodgers@dcs.qmw.ac.uk (Angus H Rodgers)
Newsgroups: sci.logic
Subject: Re: Multiple Truth Values
Date: 9 Jan 93 19:18:54 GMT
Organization: Computer Science Dept, QMW, University of London

In <1993Jan9.185347.9555@CSD-NewsHost.Stanford.EDU>
pratt@Sunburn.Stanford.EDU (Vaughan R. Pratt) writes:

>Any culture with a weak work ethic is vulnerable to the
>oversimplification that there are just two truth values.

That's a beautiful-looking generalisation, but I don't understand
quite what it means or how you arrive at it. Can you expand on it
a bit?

>The algebra of truth
>values is a rich subject that is not adequately represented by the
>passage from {0,1} to its power set, to say the least!

Do you have any references to more adequate studies of the algebra(s)
of truth values?
--
Gus Rodgers,  Dept. of Computer Science, | Cinema's worst romantic dialogue? --
Queen Mary & Westfield College, Mile End | "Mechagodzilla's brain is  installed
Road, London, England.   +44 71 975 5241 | in my stomach!" "I don't care if you
E-mail (JANET):   arodgers@dcs.qmw.ac.uk | are a cyborg  --  I still love you!"
Xref: sparky sci.philosophy.tech:4684 sci.logic:2538
From: PL436000@brownvm.brown.edu (Jamie)
Newsgroups: sci.philosophy.tech
Subject: Re: Colors, Schemes, Theories
Date: Tue, 12 Jan 1993 16:22:37 EST
Organization: Brown University - Providence, Rhode Island  USA
NNTP-Posting-Host: brownvm.brown.edu
News-Software: BNN via BNN_POST v1.0 beta

>I mean exactly what is contained in Berlin and Kay (1969?/1991?).

Can you give a more complete citation? I would like to look at the
article.

>That we all have the same visual apparatus, and therefore make the
>same similarity judgments is not at all to the point.  I mean simply
>that different cultures divide up the spectrum (a theoretical claim,
>by the way) in different ways. E.g. they call two shades species of the
>same color where we call them different colors. No controversy here.

I see. Thank you for explaining this.

Here is how I would gloss the phenomenon:
by "color" those people mean something different from what we mean.

Is that how you would gloss the phenomenon, or were you thinking of
some other point?

And, what does it have to do with scientific realism?

Jamie
Newsgroups: sci.philosophy.tech
From: sasghm@theseus.unx.sas.com (Gary Merrill)
Subject: Re: Which theory before observation ?
Originator: sasghm@theseus.unx.sas.com
Date: Mon, 11 Jan 1993 14:07:58 GMT
Organization: SAS Institute Inc.


In article <schiller.726741489@hpas5>, schiller@prl.philips.nl (schiller c) writes:
|> christo@psych.toronto.edu (Christopher Green) writes:
|> 
|> >>In article <schiller.726487694@hpas5> schiller@prl.philips.nl (schiller c) writes:
|> >>>My position as a scientist is that facts, i.e. the  results of observation,
|> >>>are the basis of theories. There are no "well-known" flaws of this position. 
|> >>>
|> >I'm afriad that this is simply ill-informed. The observation-theory distinction
|> >has long been a matter a controversy in philosophy of science. The best-known
|> >"flaws" are put forward in Putnam's "What theories are not."  The position
|> >outlined there is a little technical, but the central example is that one
|> >cannot establish, through obsevation, that a thing is red unless one has
|> >a conceptual scheme for colors that includes red in advance.
|> 
|> You are right: one needs a concept of red. But a concept and a theory
|> are two different things. Red is a concept formed by children
|> before they are six months old, and it gives a name to certain class 
|> of colours. When a child says: "it is red", it just says, "it has a similar
|> look than all the previous things I have observed, which I call red".
|> The statement "It is red" therefore just compares different observations.
|> Not much of theory there.
|> 
|> 			Christoph Schiller
|> 

You are right: one needs a concept of electron. But a concept and a theory
are two different things. Electron is a concept formed by physicists
before they are given degrees, and it gives a name to certain class 
of particles. When a physicist says: "it is an electron", it just says, "it has a similar
look than all the previous things I have observed, which I call an electron".
The statement "It is an electron" therefore just compares different observations.
Not much of theory there.

I wonder why the physicists need so much more funding than do the children.
Facts are facts?

-- 
Gary H. Merrill  [Principal Systems Developer, C Compiler Development]
SAS Institute Inc. / SAS Campus Dr. / Cary, NC  27513 / (919) 677-8000
sasghm@theseus.unx.sas.com ... !mcnc!sas!sasghm
Newsgroups: sci.philosophy.tech
Subject: Re: Philosophy before science ? (was : S
From: Hakki_Kocabas@kcbbs.gen.nz (Hakki Kocabas)
Date: 7 Jan 93 23:35:50 GMT
Organization: Kappa Crucis Unix BBS, Auckland, New Zealand

  
> While in general I agree with your response to the simplistic and  
> uncritical view expressed above, the view you express here is also  
> a bit simplistic.  For example, it appears to leave no room for the  
> existence of a phenomenon that is anomalous with respect to the  
  
'existence of a phenomenon' is beyond my sphere of interest at the  
moment. It is in deep oceans or should I say in a drop of grammar :-)  
  
> current theory, thus prohibiting theory change (also, apparently,  
> making it unnecessary!).  
  
In simple words, what you want to say is this; this theory is  
useless to communicate with our colleagues in our activities   
any further...we don't know what to say in accordance with this  
theory...but then What ? What can you say ? According to what ?  
   
> Gary H. Merrill  [Principal Systems Developer, C Compiler Development]  
Newsgroups: sci.philosophy.tech