Meaning, Truth-Conditions and Defeasibility
R.M.Petty
warented long ago but I only now feel that we are on the same page, as it
were.
JL Speranza made many interesting comments. There is really only one that
I wish to comment on.
He writes:
> In this post I shall address some of the topics raised by R M Petty in
> his interesting communication. I'm still elaborating on the issues as the
> thread develops, thus my remarks should in no way be seen as conclusive.
> Also, if my overall tone is rather critical, that may well be due to my
> current scepticism as to how constructive one can be in this field. I hope
> my post may clarify my position regarding some terminological or
> definitional issues.
> With regards to Schiffer's treatment of Dummett, R M Petty writes: My
> intuition is that [Schiffer] has not quite got Dummett right, although..
> this is really nothing more than a guess". Re: Schiffer's
> counterexample to Dummett, (1) Thales did not begin to walk until he was 13
> months old, he writes:
> "My intuition is that [the 'Thales' sentence] is an EFFECTIVELY UNDECIDABLE
> statement"
> Maybe. Schiffer's point is that it is also MEANINGFUL, and so that the
> onus probandi is on Anti-Realist Semantics as how to explain such semantic
> dimension.
Hum, in re-reading the last ten pages or so of Truth I found that Dummett
seems to claim that statements that are undecidable are also unwarranted.
Previous to this re-reading I thought that Dummett held there were
statements that one could assert with warrant but were also undecidable.
This view may change in later essays but this is beside the point of Truth.
I am not yet sure how this may impact the claim that these sentences are
meaningful. One option is that Dummett could merely claim that they are not
meaningful but it is more likely, I think, that he would say that they
appear to be like statements that are effectively decidable thereby giving
us the illusion of meaningfulness.
> R M Petty writes: "[1] is EFFECTIVELY UNDECIDABLE for the reasons
> Schiffer gives ... There is no clear method of decidablity. As such one
> ought to speak of [warranted] ASSERTABILITY-conditions rather than
> truth-conditions. It strikes me that Schiffer's description DOES MEET with
> the conditions of warranted assertion: ... (1) is grammatically well-formed,
> speaks of a figure that is part of our cultural history, and
> supplies information about the biological development of said figure. I am
> sure this is not an exhaustive list of assertability-conditions even if it
> is an accurate one".
> Myself, I would take the exegesis referred to by R M Petty (that (1)
> speaks of "a figure that is part of our
> cultural history and supplies information about the biological development
> of said figure") to be about the 'meaning' of (1), rather than its
> warranted-assertability conditions. 'Assertability-conditions' (i.e. the
> utterer finding himself in a position that warrants the assertion of (1))
> would rather include to be the utterer's belief that 1. There is a written
> work from the time of Thales, and 2., that that written work says among
> other things, as translated into English, that Thales did not begin to walk
> until he was 13 months old'. Now, this can always be refuted by some
> SPECIFIC DEFEASIBILITY-CONDITION that shows that the written work (referred
> to in the warranted-assertability condition) is proved to be a fake (Perhaps
> similarly for 'the cat is on the mat').
> R M Petty writes: "What makes me think this is a misunderstanding ... of
> Dummett [by Schiffer] is that Schiffer writes as if VERIFICATION is
> interchangeable with TRUTH. ... He commonly pairs [verification] with
> falsification ... I think he has misunderstood the point of saying that (1)
> is EFFECTIVELY UNDECIDABLE".
> It seems to me that Schiffer is NOT concerned with (1)'s truth-condtion,
> only its direct-verification conditions. I take that (1)'s truth conditions,
> as per Schiffer and Davidson would merely mention the
> paratactical Tarskian theorem ('Thales did not begin to walk until he was 13
> years old' is true iff Thales did not begin to walk until he was 13 years
> old), or else some specification of the right-hand side of such
> biconditional (eg. 'the philosopher called Thales did not begin to
> articulate his feet to move his body about and without the aid of his hands
> until at least the 390th day after he was born).
> R M Petty writes: "It strikes me that the point of classifying some
> statements as EFFECTIVELY UNDECIDABLE is to separate those statements for
> which we cannot TELL if they are true, false, or have some third value." He
> quotes from Dummett's 'Truth' "to the effect that, for those statements that
> are EFFECTIVELY UNDECIDABLE, or for those statements that are properly
> subject to 3 truth-values, [...] it may be better if we just assume they are
> FALSE":
> "In most philosophical discussions of truth and falsity, what we really
> have in mind is the distinction between a designated and an UNDESIGNATED
> VALUE, and hence choosing the names 'truth' and 'falsity' for particular
> designated and undesignated values RESPECTIVELY will only OBSCURE THE ISSUE"
> (PL p63, TOE p14app) (Emphasis mine. JLS).
> P M Petty writes: "... I admit that I am not entirely comfortable with my
> understanding of this passage ... but I read the class of DESIGNATED
> TRUTH-VALUES as interchangeable with the class of effectively decidable
> statements and UNDESIGNATED as EFFECTIVELY UNDECIDABLE statements"
> Allow me to disagree. Note that Dummett is using 'respectively'.
> 'Undesignated' seems to mean there just 'false', i.e. the class of
> utterances one can DECIDE to be not 'true'. I'd take the
> 'designated/undesignated' terminology as a logical technicism, brought e.g.
> to mark eg a formal vs informal interpretation of a
> calculus. Thus, one may have ''p and q' is true iff both conjuncts are true'
> (or ''p & q' is 1 iff both p and q are 1'), with 'false' (or 'O') as
> UNDESIGNATED. Alternatively, in ''p and q' is false iff at least one conjunct
> is false' (or ''p and q' is 0 iff at least one conjunct is 0') it is rather
> 'true' (and '1') which are undesignated.
> P M Petty adds: "It may be better to assume EFFECTIVELY UNDECIDABLE
> statements are FALSE in order not to OBSCURE THE ISSUE [as per Dummett's
> wording], 'the issue' being whether or not we have a method of decidability".
> Well, wouldn't THAT obscure the issue? :). I would think that if some
> utterance is held to be FALSE, then it is DECIDADBLE, in fact DECIDED that it
> is NOT TRUE. The problem (or Dummett's Dilemma with the Effectively
> Undecidable as I may call it) is that, by definition, there is no way (or
> algorithm) of decididing if a given 'p' is true or false (eg Schiffer's
> Thales sentence). The paradox being that such utterances still 'mean'.
First of all you are quite right, I have miss-read Dummett in the quote I
have given but this is the issue on which I wish to ask for some
clarification. What exactly is the paradox? I grant that my previous
reading of Dummett may have resulted in a paradox but I am not sure that
Dummett is subject to this claim.
> R M Petty: "How Schiffer's terminology may be leading to a
> misunderstanding is that his use of 'verification' may have roughly the same
> meaning as 'method of decidability', provided the former is meant to convey
> that we have the effective ability to verify that ['p'] is either true or
> false. ... To verify ['p'] would, then, be to determine whether or not [it]
> is true or false. Unfortunately, Schiffer couples
> 'verify' with 'falsify' as if to verify something is to find it to be true.
> It may be that Schiffer's terminology is an example of the exact type of
> OBSCURANTISM that Dummett refers to in the passage above"
> Allow me to disagree again. I don't quite think that in equating
> 'verify' as 'finding
> something to be true' Schiffer is being obscure. But then I don't think
> Dummett is in any case having such case of 'obscurantism' in mind. Dummett's
> reference to 'obscuring the issue' seems to be related to the
> designated/undesignated distinction, i.e. to the idea that replacing talk of
> 'truth' by talk of 'designated value' (where this can be 'true', '1', or
> what not) would be (in an essay entitled 'Truth') a case of 'obscurus per
> obscurius'.
> R M Petty: "[This] terminology may allow Schiffer to slide from the
> issue of whether or not ['p'] is CAPABLE of being found to be true or false
> to an attempt to find ['p'] true or false, as if there were no distinction.
> This is the value, and point, of Dummett's distinction and one I hope I have
> made it clearly".
> I agree there IS a distinction between a factual statement ('p' is
> verified') and a modal one ('p cannot be verified), and Dummett has indeed
> brought to focus the class of effectively undecidable statements. Schiffer's
> contribution is merely to point out that those statements still seem to have
> a 'meaning'... Note that in Remnants of Meaning, Schiffer is examining what
> constructive proposal may be behind anti-realism, namely, what a
> defeasibility-, direct-verification- , or
> warranted-assertability-conditional semantics may have to offer.
I am glad to hear that Schiffer is engaged in a project to highlight the
constructive aspect of anti-realism. Wright does this as well. However, I
would like to point out that having meaning and seeming to have meaning are
distinct things and this distinction is an important one. As you latter go
on to suggest, Dummett does suggest that talking about truth conditions of
effectively decidable statements is, in his word, absurd.
At this point it seems to me that Dummett's dilemma my be more properly
termed Petty's dilemma.
Yours,
R. M. Petty
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