[lit-ideas] Re: Post the letter or burn it
- From: Jlsperanza@xxxxxxx
- To: lit-ideas@xxxxxxxxxxxxx
- Date: Sat, 13 Aug 2011 16:34:02 EDT
In a message dated 8/13/2011 4:10:04 P.M. Eastern Daylight Time,
donalmcevoyuk@xxxxxxxxxxx writes:
we do speak, imperatively, that we ought to "Post the letter or burn it"
we are not merely saying that only posting the letter is the morally correct
action; on the contrary we are positing burning the letter as a viable
alternative and one required if we do not post the bloody thing.
---
Perhaps we can see the analogy, though, by reverting to Popper (or Grice
for that matter) on 'therefore', i.e. arguing. I will use two devices:
-------
The line, that is, to divide premise(s) from conclusion:
p
-----
q
and the otiose
"∴"
To mean, 'therefore'.
I claim, indeed that
Post the letter!
_______
∴ Post the letter, or burn it!
--------- This argument Hare, following Grice, calls 'trivial'.
----
On the other hand, as McEvoy suggests, the following DOES not follow:
Post the letter, or burn it!
-----
∴ Burn the letter!
So, it seems that the apparent paradox resolves around:
the triviality of a piece of arguing, that is so trivial that no one would
(one expects) make.
And the INVALIDITY of another piece of reasoning.
Or something like that.
----- I agree with McEvoy that a bit of empiricism and such gets into the
picture, in that, as Ramsey quotes from Lewis Carroll:
--- "Either the song will bring tears to your eyes, or..."
--- "Or what?" asked impatient Alice.
--- "Or else it won't, you know".
In a way, this parallels the reasoning of Helm's dog:
"You are leaving, are you?"
----
Yet, as Ramsey notes, following Aristotle, if we disallow bivalence tout
court -- it is dubious whether statements about the future are either true or
not --, it is NOT analytic that 'or' gets the truth-table it gets.
Similarly for imperative counterparts. It is quite a decision, on the part of
the
logician, say, to introduce 'or' like that (as Gentzen, or Grice does). Or
not, of course.
Cheers,
Speranza
---- I wonder if wiki has all this under 'free choice' items, and such.
Should check it out. I know the earliest literature is traced to Alf Ross who
published the thing in TWO venues back in the early 1940s.
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