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Re: [ontolog-forum] Ontology, Information Models and the 'Real World': C

To: "[ontolog-forum]" <ontolog-forum@xxxxxxxxxxxxxxxx>
From: Ingvar Johansson <ingvar.johansson@xxxxxxxxxxxxxxxxxxxxxx>
Date: Wed, 30 May 2007 10:36:39 +0200
Message-id: <465D3797.2000902@xxxxxxxxxxxxxxxxxxxxxx>
Dear John and Pat,    (01)

John F. Sowa schrieb:
> Ingvar,
> IJ> Are you denying the old truth: 'same meaning, same reference'?
>  > To me, this truth implies 'same proposition, same aboutness',
>  > which you are denying.
> What I would call into question is the word 'same'.  Following is
> another of my favorite quotations from Whitehead, _Modes of Thought_:
>     In logical reasoning, which proceeds by use of the variable,
>     there are always two tacit presuppositions -- one is that the
>     definite symbols of composition can retain the same meaning
>     as the reasoning elaborates novel compositions.  The other
>     presupposition is that this self-identity of each variable can
>     be preserved when the variable is replaced by some definite
>     instance.... The baby in the cradle and the grown man in middle
>     age are in some senses identical and in other senses diverse.
>     Is the train of argument in its conclusions substantiated by
>     the identity or vitiated by the diversity?  (p. 146)
> If you take a position that is both realist and fallibilist, you
> have to admit that reference, as well as truth, is fallible.
>       (02)

I don't get it. How does this quotation answer my question to you? I 
wholeheartedly admit that in everyday speech and in 
empiricial-scientific speech reference and truth are fallible, but in 
both contexts it seems to hold true: (i) 'same meaning implies same 
reference' and (ii) 'same proposition implies same aboutness'.    (03)

> My approach is to develop a two-valued logic, which supports
> contexts (and metalanguage about the contexts) in which propositions
> may have different truth values in different contexts -- and which
> allows metalevel reasoning about those truth values in a containing
> context.     (04)

I have earlier on this forum criticized you for *labeling* one of your 
logical constructions a definition of proposition, since what you 
defined did not have the feature of being a truthvalue bearer. Now, I 
want once more to complain about your way of using the term 
'proposition'. If in the whole of modern philosophy before you (and some 
colleagues) entered the scene, the term 'proposition' has been used 
(even by Quine) in such a way that a proposition cannot possibly change 
truthvalue, why can't you use some other term in your enterprise? I make 
a proposal below in my answer to Pat.    (05)

Pat Hayes schrieb:
>> IJ>
>> > Are you denying the old truth: 'same meaning, same reference'?
> Yes. The whole point of introducing 'contexts' is to provide for 
> alternative views of what is true and what is not. The very same 
> proposition may, in another context, have a different truthvalue. That 
> is not to say it ACTUALLY has that truth-value: the ACTUAL truthvalue 
> of any proposition is a given. But there is some utility in allowing 
> the existence of entities which correspond to alternative ways the 
> world might be (it allows one to reason about counterfactual or 
> fictional circumstances, for example.) And when one does allow such 
> things, it is pointless to insist that they must correspond to the way 
> things actually are. So, we allow that a proposition may have a 
> different truthvalue "in" a context than it has in fact. This does not 
> actually make its truthvalue different from what it is, it simply 
> introduces a new notion of truth-in-a-context.    (06)

Implicitly, I take it, it then also introduces a new notion of 
'proposition-in-a-context' that ought not to be conflated with the 
traditional philosophical and logical term 'proposition'. A 
proposition-in-a-context can change truthvalue, a proposition cannot. 
Stated in this way, I have no objections.    (07)

Ingvar    (08)

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