--- On Tue, 29/9/09, Richard Henninge <RichardHenninge@xxxxxxxxxxx>
wrote:
> I pray, and I think we should all so pray that Donal is
> indeed "mistaken" that "any assertion, including those as to
> the validity of deductive inferences, is possibly or
> potentially mistaken." This is an extremely radical
> position, fit, metaphorically speaking, to put quicksand
> under the basis of all our mutual understanding, unless
> Donal is saying, in effect, "not to worry--even if a given
> assertion as to the validity of deductive inferences is
> mistaken, that would not preclude the validity of deductive
> inferences so asserted."
Comments:
1. The last statement does not follow from the premiss I used: from the
fact
that the validity of a (putative) deductive inference "is possibly or
potentially mistaken" (my premiss) we cannot leap to the conclusion that
it
"is mistaken" (Richard's conclusion).
2. The conclusion anyway is in itself not 'sound' - "if a given
> assertion as to the validity of deductive inferences is
> mistaken, that would not preclude the validity of deductive
> inferences so asserted" is a false claim. Deductive inferences if valid
> are
not mistaken - and asserting their validity if not mistaken either.
3. No such absurd conclusion can be derived from my post for the reason
at
1.
4. Nor does it follow imo that P's POV "is an extremely radical
> position, fit, metaphorically speaking, to put quicksand
> under the basis of all our mutual understanding". At most it implies
> that
even our "mutual understanding" is fallible or prone to error or is
itself a
form of conjectural knowledge - anyone who has had the common experience
of
realising the "mutual understanding" they had supposed was not in fact so
mutual, will hardly think this "an extremely radical position".
5. I mentioned "learning". We forget that even "p & q, therefore q" is
learnt
in an important sense. Imagine a test where members of the public can win
a
fortune or save the life of a loved one by answering one question
correctly
in the next 24 hours; if they answer wrongly the test finishes; if they
answer 'don't know' they are given another question. My conjecture is
that if
the stakes were high enough and the first question was "Is it true that
'If p
& q, then q'?" most people would say 'don't know', hoping they would get
another question where they felt on safer ground. If so, this tells us
that
even what seems cast-iron logically has for many what P referred to as
its
"moment of uncertainty".
>I'm afraid it is significant, that
> is, it is "educational" that Donal is having semantic issues
> with the word "validity."
As RP points out, given the semantics of "validity" and "soundness" as
logicians use these terms, it is Richard who has the "semantic issues"
with
"validity".
>A sound argument is not a valid
> argument.
As logicians use the terms, it is.
>The avoidance of contradictions in one's arguments
> is one step in the direction of a sound argument, but no
> guarantee of its validity.
This was neither explicitly not implicitly denied by post, which asserted
rather that the validity of a deductive inference depends on there being
no
counter-example (i.e. where using the 'inference' a false conclusion
might be
'deduced' from true premisses).
> I believe it was also enlightening, revealing,
> "educational," that Donal once maintained that the better
> argument often loses.
Yes I maintained this without quantifying "often", as once or twice a
lifetime might be thought "often" enough. Given the history of ideas it
would
seem to me it happens more often that that.
Richard now has a spring-board to go off the deep end, as follows:-
>He somehow conceives of arguments as
> being measurable, rankable on some kind of objective scale
> of validity, with the surprising consequence being that the
> better argument achieves, so to speak, an inner victory,
> something of a moral victory, because it is, "in fact,"
> right, or, in Donal's terms, valid. But no mere mortal can
> determine the true validity, literally the "strength" of an
> argument, its "rightness," somehow objectively. Not to put
> too fine a point on it, but is not Donal's--for the most
> part--uncritical acceptance of Popper simply the outgrowth
> of his philosophical tendency to take his current favorite
> philosopher as the gold standard of argumentation?
Well, this is almost too much to pick apart or even take in. I don't
think my
relationship with Popper's work is accurately surmised as one of
"uncritical
acceptance". Nor did I use the terms "measurable, rankable" - as if there
were an "objective scale of validity" for argumemts the way the metre bar
might be an "objective scale" for measurement or ranking people by
height: a
better term than "measurable" or "rankable" might be "assessable" or
"open to
evaluation". When we assess or evaluate for validity or soundness we do,
if
we are serious, work to the ideal of an "objective scale" rather than a
merely subjective one - even if we are a "mere mortal". What is the
"philosophical tendency" that denies or decries this, and is it not based
on
"uncritical acceptance" of certain assumptions? (For example, the
assumption
that we cannot properly take the view that knowledge is both always
conjectural and that it has also an "objective" aspect that transcends
our subjective knowledge as 'knowing subjects'.
As to my "current favorite philosopher" one might think my posts
fluctuate in
this-week's-fashion fashion. They don't.
Donal
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