[lit-ideas] Re: "Must We Mean What We Say?"
- From: Donal McEvoy <donalmcevoyuk@xxxxxxxxxxx>
- To: lit-ideas@xxxxxxxxxxxxx
- Date: Wed, 24 Oct 2007 21:59:09 +0100 (BST)
--- Jlsperanza@xxxxxxx wrote:
> Let's see:
>
> (1) The plant is not important to the students in this classroom.
>
> This contains a negative, so it's basically meaningless
Wrong, even if your arg. that we can't prove a negative were true: for we
should not conflate meaning with proveability (Popper et passim). 'God
exists' and 'God does not exist' may neither be proveable but that hardly
warrants saying they are both therefore meaningless - especially as, as Pop
pointed out, such a criterion of meaning is itself unproveable and therefore
accordg to itself meaningless.
>("There are no
> weapons of mass distruction". You cannot prove a negative.
Yes you can if by 'prove' we mean 'test': 'there is no swan in the bathroom'
is a claim that is proveable in the sense that if we look and find no swans
we have proved it - just as much, or as little, as if we would have 'proved'
there is a swan in the bathroom if we had found one. So 'restricted negative
existential statements' are 'proveable' just as 'restricted existential
statements' are proveable. They are logical symmetrical in this respect.
The problem, as may be the case with WOMD, is that an 'unrestricted negative
existential statement' is only assymetrically testable: it can be disproved
by finding a counter-example; but no absence of a counter-example in a
particular place can prove it - since such an absence would not 'prove' there
was not a counter-example somewhere else.
However, despite this logical assymetry, we can still regard the absence of a
counter-example as a 'proof' of an 'unrestricted NES' where 'proof' is not
used to mean 'logically proven' [or inductively proven] but 'has survived
severe attempts to refute it by finding a counter-example'.
Note: WOMD are not debated in terms of unrestricted NES - we are looking for
them on earth, particularly in Iraq [a restricted area from a logical POV].
So the example is doubly unfortunate - and a scorched earth search of all of
that area would surely be accepted by most reasonable people as good evidence
as to whether (or not) they existed [as per the swans in the bathroom].
I then surveyed your next two points. I was about to pour scorn on the first
when I ob'd this.
> (3) I bet it takes you a long time to get to your classes.
>
> This is what Austin called a 'performative' thus neither true nor false.
Then I op'd or inf'd that you were of course joking all along.
Ooops.
Donal
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