Presuppositions and Pronouns - Nijmegen Centre for Semantics

22 Presuppositions and Pronouns
Note, by contrast, that the presupposition that a group of girls is contextually
given, which is triggered by the definite NP the girls, will go through no
matter what.
For good measure, here are some further examples that demonstrate how
presuppositions and implicatures diverge:
(43) Wilma hopes that }
Wilma doubts that. .
Wilma
Can doubts
tell that ·f
if
Fred kissed some of the girls. gIrlS.
C you t e 11 me I
Let's go and see if
According to my intuitions, none of these sentences definitely imply that
Fred didn't kiss all the girls, and at least some of them definitely don't imply
this. By contrast, each of these sentences clearly implies, in the absence of
evidence to the contrary, that there were girls. Presuppositions show
projection behaviour; implicatures do nothing of the sort.
If it cannot be shown that conversational implicatures are liable to escape
from embedded positions, as presuppositions are, then a fortiori it cannot be
shown that they are blocked or suspended under some circumstances. Cases
like the following, for example, do not show that some implicatures exhibit
projection behaviour:
(44) a. The water is warm, and perhaps even hot.
b. The water is warm. In fact, it is hot.
c. The water is warm, if not hot.
Horn (1989: 234-235) makes a distinction between implicature blockers and
implicature suspenders. In (44a) an implicature is blocked, according to
Horn: in this case the speaker explicitly conveys that, for all he knows, the
water may be hot, and therefore the implicature that the water is not hot,
which would normally be licensed by the use of the scalar adjective warm, is
blocked. In (44b) this implicature is suspended: the first sentence licenses the
implicature, but it is removed by the second statement, which contradicts it.
Finally, (44c) is ambiguous and may be construed as an instance either of
suspension or blocking. In the former case, the speaker is taken to convey
that he doesn't know if the water is hot; in the latter, his statement implies
that the water is not hot.
Judging from the way he describes what is going on in (44a-c), Horn must
be assuming that the quantity implicature induced by warm exhibits
projection behaviour. But it doesn't really. Consider (44b) first. Here the
implicature is licensed by a simple sentence, only to be cancelled by the next
statement. This could never happen to a presupposition. Compare (44b)
with: