Dummett cited by Grice in "Logic and Conversation"

Speranza

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Grice, "Logic and Conversation" -- The 4th William James Lecture, for 1967 -- 'Indicative Conditionals', WoW, p. 79:


"Dummett and Kripke suggest that
we distinguish between

(1) the notion of the probability
of a conditional relative to certain
evidence h,

-- a notion which is not altered if,
for that conditional, we substitute its
standard counterpositive, or (for that matter)
its standard disjunctive counterpart;

for

(if p, q)/h

is equivalent to

(if not q,not p)/h,

and also to

(either not p or q)/h;

and

(2)

the notion of conditional probability
as it is exemplified in the
probability of p, relative to both
q and h,

--- a notion which CANNOT be treated
as identical with the probability
of the negation of q, relative to
the conjunction of the negation of
p and h."

"They [Dummett and Kripke] further
suggest that the puzzle about Yog and
Zog should be taken to relate to
conditional probabilities and not to
the probability of conditionals."

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"I do not propose to quallel with
this solution to the paradoxical
aspect of my example."