All ravens are black
Poe saw a raven
----
Poe saw something black.
---- An albino raven is still a raven, so we have to be careful here. And
surely other ravens perceive that a raven is albino, when they see it.
*Hopefully they perceive bullshit.
On Mon, Apr 27, 2015 at 1:19 AM, Redacted sender Jlsperanza@xxxxxxx for
DMARC <dmarc-noreply@xxxxxxxxxxxxx> wrote:
In a message dated 4/26/2015 2:23:47 A.M. Eastern Daylight Time,
donalmcevoyuk@xxxxxxxxxxx writes in "Re: The King is not a subject.":
"[Geary]'s view of colour as perceived wavelengths is quite compatible
with Tarski's theory of truth and compatible with the view that we can make
true and false claims about colour - these claims may be true or false
claims
about colour as perceived wavelengths."
Indeed. But Tarski was being simplistic. He wrote his thing in Polish,
which he later cared to translate to German.
Every Eskimo school boy knows that Tarski's problem is not with 'white',
but with 'snow'.
Tarski's big problem is not with "p"
as in
"p" is true iff p.
but with "q"
For complex propositions, Tarski uses:
"White is snow or grass is green."
And surely every Welsh school boy knows that grass is 'glas', not perhaps
'green'.
Again, it IS different in Polish (and also different in German, to which
Tarski cared to translate his essay).
McEvoy goes on:
"There is no good argument in [Geary]'s post for saying that, if we view
colour as perceived wavelengths, then we must abandon talk of true and
false
and replace it with "assertability" - nor is there any clear argument that
shows that "assertability" could righly replace talk of 'true' and
'false',
or that shows "assertability" would not raise analogous problems to
applying 'true' and 'false' and so only shift the problems. Though
[Geary]'s view
is quite compatible with Tarski's theory this is really because Tarski's
theory of truth is compatible with many different metaphysical,
philosophical positions. While Tarski rehabilitates the notion that
"'Snow is white' if
and only if snow is white" [i.e. the correspondence theory of truth], his
rehabilitation leaves open how we know "Snow is white", or whether "snow"
or "white" are objects in an external world or merely constructs of an
internal world of the mind etc. That is, Tarski's theory does not prove or
disprove either some form of realism or some form of idealism. That said,
Popper
quite legitimately brings Tarski to bear in defence of his form of
"realism": as Tarski's theory operates at a purely 'ontic' level,
independent of
'epistemic' considerations, it therefore tacitly uses a distinction
between
the 'ontic'/what exists and the 'epistemic'/what can be known, and to draw
this as a distinction that can never be collapsed is in effect to accept a
form of realism."
I think Tarski was looking for an example. Toulmin uses:
"The cat sat on the mat" is true iff the cat sat on the mat.
Tarski needed instances for p and q in complex formulae, so he came up with
"Snow is white or grass is green."
Later came Reichenbach with his infamous:
"And ravens are black."
In "How to do things with words," J. L. Austin criticises Reichenbach as
simplistic, and comes up with
"All swans are white".
For Austin notes that even if we KNOW that there are Australian swans which
are black, and South American swans which are partly white and partly
black (the 'black-necked swan' of Chile and Argentina), 'we can ignore
them.'
Austin's interest is in the use of quantified formulae ("All swans are
white"), whereas Tarski is IMPLICATING a quantifier ("All snow is white,
or all
grass is green").
"White" and "green" -- the adjectives used by Tarski -- quite don't
compare: white is not a colour, but a value, as most philosophers of colour
agree. Ditto for 'black' as in Reichenbach's infamous example of
nomological
explanation:
All ravens are black
Poe saw a raven
----
Poe saw something black.
---- An albino raven is still a raven, so we have to be careful here. And
surely other ravens perceive that a raven is albino, when they see it.
Cheers,
Speranza
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