Presuppositions and Pronouns - Nijmegen Centre for Semantics

198 Presuppositions and Pronouns
There has been some discussion in the philosophical literature whether the
principle of conditional excluded middle is valid or not:
(51) (ifp, then q) or (ifp, (if/, then not-q)
Stalnaker (1981) argues that this principle is a valid one; Lewis's (1973)
analysis of conditionals implies that it isn't. Consider the following pair of
examples, devised by Quine (1950:14): 14):
(52) a. If Bizet and Verdi had been compatriots, Bizet would have
been Italian.
b. If Bizet and Verdi had been compatriots, Verdi would have
been French.
While on Stalnaker's analysis both conditionals would lack a truth value, on
Lewis's account they would both be false. Although I have a slight preference
for Stalnaker's position, I have no particularly strong opinion one way or the
other, and mainly want to note here that the analysis of conditionals I
propose throws a new light on this issue. If if-clauses //"-clauses are presupposed, then
the question whether (51) is valid is tied up with the problem of
presupposition failure. It may be argued that the presupposition triggered by
an if-clause //"-clause may fail, for instance because the proposition it presents as given
is insufficiently specific. If this is the case, we are in the empirical quicksand
briefly surveyed in § 1.6. This is doesn't improve the situation, to be sure, but
at least it gives us a better idea where we are.
It is an almost stale observation that there is a close connection between ifclauses
and sentences beginning with 'Suppose that...', .', 'Assume that...',
.',
if-
'Given that. ....', .', and so on. This connection is noted by Kamp (1988), too,
but he concedes that his version of DRT does not explain it (cf. also Kamp
and Reyle 1993: 141-146). On the presuppositional analysis of conditionals,
by contrast, an explanation readily suggests itself.
(53) a. Suppose Fred is a Freemason. Then Barney is a Freemason,
too.
b. If Fred is a Freemason, (then) Barney is a Freemason, too.
Stylistic nuances aside, (43a) and (43b) are equivalent. In the first half of
(43a), the speaker invites his audience to suppose the world to be such that
Fred is a Freemason, and in the second half he says that in such a world
Barney is a Freemason, too. Interestingly, (43b) can be paraphrased in
exactly the same way.lO 10 To explain this convergence, we only need to assume
10 10 Note, incidentally, that (49) is is matched by:
Suppose we get a taxi, and suppose we aren't held up in a traffic jam, and suppose
there isn't an air strike; then we'll be in Timbuktu before teatime.
See Kamp (1988) for further discussion of this sort of example.