An important, I hope, ps (or postscriptum, as St. Aquinas would prefer) to my
previous, “Grice and Popper on the implicatures of ‘know’” which is ultimately
of course about Rudy’s seminal JTB theory of knowledge. In particular, let’s
consider his (Rudy’s, that is) utterance, as reported by McEvoy – which in my
previous post came out as being number iv.
iv. I did not know that.
(McEvoy: ““I know everything”. Things dipped - and sometimes Rudy would later
say “I didn’t know that””).
It was the logician R. M. Harnish (a Fregeian at heart) who emphasised this in
his seminal (if one must overused this word) “Logical Form and Implicature”.
Grice’s approach is slightly different in that in Way of Words he dismisses the
JTB theory of knowledge for one of the ‘causal’ type (alla Goldman) – (Grice
finds the JTB theory too ‘strong’ – and like his tea, he liked it strong but
never ‘too strong’).
Harnish applies Grice’s approach (via the conversational maxim of
informativeness – ‘cooperate with your co-conversationalist by being as
informative as he think you should be”) to the JTB theory using an example
whose second move is exactly like (I love this redundancy, ‘the same exact’) as
xvii. A: I did not know that you were pregnant.
B: You still don’t.
Harnish spends twenty-five minutes analysing the disimplicaturing of B’s
conversational move (Grice speaks of conversational moves in the conversational
game that abides by conversational rules). B’s utterance is best expressed as:
xviii. You still do not know.
Obviously, it involves the “~” operator of negation. So, Grice’s solution is to
consider that, for a Platonist, the analysis:
xix. K =df JTB
is a matter of entailment – each prong, J, T, and B – constitutes a necessary
condition, and the trio forms the sufficient set. But the negation is another
For, what does the “~” apply to?
We have three possibilities, Harnish notes: “~” can apply to “J”; it can apply
to “T”; or finally, it can apply to “B”. I.e. B may be rejecting
a) A is justified in believing that B is pregnant.
b) “B is pregnant” is true.
c) A believes that B is pregnant.
Harnish notes that the ‘preferred’ reading is (a): “You still do not know that
I am pregnant” is a denial of A’s utterance to the contrary effect, “I did not
know that you were pregnant” (implicating, “You are pregnant”). There is a
further disimplicature to the effect that B is communicating to A that B is NOT
With Rudy it may all be different, but you knew that.
Obligatory Popperian Comment: Popper disliked the Griceian types of analysis of
‘know’ because Popper disliked Oxford in general – and these types of analysis
have come to be known as representing what Grice, jocularly, calls, “the Oxford
school of ordinary language philosophy” (“Of course, everybody who’s been to
Oxford, _knows_ there’s no such thing! We dislike the word ‘school’ for
starters!). This explains why Popper taught, rather, in London – and would
endorse Bergmann’s view of Grice as a ‘futilitarian’.