Presuppositions and Pronouns - Nijmegen Centre for Semantics

Presupposition 9
there is a way of negating (22a) that does not preserve the inference that the
speaker takes (22b) to be true:
(23) Who didn't kill Caesar
But this does not prove that (22a) doesn't presuppose (22b). If (22a) triggers
the presupposition that (22b) is true, it is presumably the entire question that
acts as a presupposition inducer. So when applying the negation test, we have
to determine, not what happens when we insert a negation somewhere into
this alleged presupposition inducer but rather what happens when a negation
sign takes scope over the question as a whole. But of course, questions are
allergic to external negation:
(24) It is not the case that who killed Caesar
If we want to prove that (22a) presupposes (22b), then it must be shown that
this inference exhibits projection behaviour, and that turns out to be difficult,
because as a rule questions cannot occur in embedded positions. There may
be one or two exceptions though.
(25) a. Fred asked who killed Caesar.
b. If Brutus wasn't in town, then who killed Caesar
c. If Ceasar was killed, then who killed Caesar
In (25a), an interrogative sentence occurs in an embedded position, and if it
were the case that we would normally infer from this sentence that someone
killed Caesar (which isn't too clear), then we would at least have some
evidence that this is a presupposition triggered by the w/z-complement. wh-complement. The
contrast between (25b) and (25c) is more significant, because in the former
case there is a strong tendency to infer that, according to the speaker,
someone killed Caesar, which is absent in the latter case. This is precisely
what we should expect if (22c) triggered the presupposition that (22b) is
true. However, this is the only halfway sound piece of positive evidence that
we have turned up so far, and even it is not beyond suspicion, because the
contrast between (25b, c) only counts if the consequent of these conditionals
is equivalent in all relevant respects (whatever they may be) to the sentence
in (22a). This might entail that (25b, c) are conditional questions, and there
has been quite some resistance against the notion of conditional speech act,
which is pointedly summarized in Walker's (1975: 145) rhetorical question:
'How can one perform a speech act in a conditional way, any more than one
can stand on one's head in a conditional way'
To sum up: there is precious little direct evidence for the hypothesis that a
wh-question w/z-question presupposes the corresponding existential declarative, because
it is so difficult for questions to occur in embedded positions, if they can
occur in such positions at all. In other words, it is a non-trivial matter to show