Presuppositions and Pronouns - Nijmegen Centre for Semantics

102 Presuppositions and Pronouns
a. But of course there are no piranhas in the Rhine.
b. But of course Fred isn't married.
It seems to me that while it is perfectly okay to cancel an ordinary
conversational implicature, it is impossible to cancel the inference which,
according to the satisfaction theory, is based upon such an implicature.
The observation which the fourth and final objection turns upon is a
straightforward one. The argument from truth-functionality is meant to
strengthen conditional presuppositions which arise, or are supposed to arise,
in an indirect way, as they are pieced together out of material contributed by
a presuppositional expression as well as its carrier sentence (for example, the
antecedent of a conditional). But actually it shouldn't make a difference how
this presupposition arises. In particular, the argument should also apply if the
presupposition were triggered directly, for example, if a conditional is
embedded within the scope of a factive predicate, as in the following
example:
(24) Barney knows that if the problem was difficult, then someone
solved it.
Here the presupposition that (19b) is true is triggered directly, and intuitively
(24) does indeed presuppose that (19b) is true, and nothing more. In fact it
would be quite remarkable if (24) would ever give rise to the inference that
someone solved the problem, except of course in contexts in which it is given
that the conditional's antecedent is true. According to the satisfaction theory,
however, (24) parallels (19a) and it should therefore be possible to find
contexts in which it implies that someone solved the problem. In fact, it
should be sufficient that a speaker who utters (24) doesn't know if the
problem is difficult, for then the two essential conditions in the truth-
truthfunctionality
argument, viz. (18b) and (18c), would be satisfied. This
prediction doesn't tally with our intuitions, however: it is obvious that even
in such a context, we wouldn't infer from (24) that someone solved the
problem.
Or consider the following discourse:
(25) I don't know if the problem was difficult or not, but I do find it
surprising that if the problem was difficult, then someone has
solved it.
A speaker who utters (25) presupposes that (19b) is true and asserts that he
doesn't know if the problem is difficult or not. But we wouldn't normally
infer from his utterance that he assumes that someone has solved the
problem. So, once more, the truth-functionality argument makes the wrong
predictions.