Presuppositions and Pronouns - Nijmegen Centre for Semantics

Modals 177 111
can be dealt with by extending the scope of the first modal. The second might
is then construed as a flag which indicates that the hypothetical context
introduced by the first is being taken up again. Thus we start out from a
structure as in (3a), which gets reanalysed into (3b), after which the
anaphoric reference marker z can be identified with its antecedent, as
desired. (3c) represents the final reading of (2):
(3) a. [: O[x: [x: thief x, break-in x], O[z: [z: take-silver z]]
b. [: [x, O[x, z: thief x, break-in x, take-silver z]]
c. [: [x, O[x, z: z = x, thief x, break-in x, take-silver z]]
This proposal has two attractive features: it captures the intuition that the
second modal in (2) extends the hypothetical state of affairs brought up by
the first, and it allows us to treat the personal pronoun in the second sentence
as a regular anaphor, which is what we wanted. But unfortunately, it is fairly
obvious that this strategy will work only as long as the modals that we are
dealing with are in the same DRS, which need not be the case, as the
following example shows:
(4) If it is possible that a thief breaks into the house, it is also possible
for him to take the silver.
Here it is not possible, obviously, to merge the two modal contexts, and
therefore our first proposal quickly breaks down.
One might think that perhaps the problem can be solved by copying over
the material in the scope of the first modal into that of the second. This
procedure allows us to deal with example (2), and it also gives acceptable
predictions for (4).
(5) a. [: [: [x: O[x: thief x, break-in x]] => ~ [: [z: O[z: take-silver z]]]
b. [: [: [x: O[x: thief x, break-in x]] => ~
[: [x, O[x, z: z = x, thief x, break-in x, take-silver z]]]
In comparison with the first attempt this one strikes me as rather clumsy,
precisely because it requires that material be copied from one corner in a
DRS to another. But apart from that it doesn't work much better than our
first strategy, as the following discourse demonstrates (this example is
Roberts's):
(6) A thief might break into the house. He would take the silver.
Here the two modals are in the same DRS, but this time they don't have the
same force, which makes it impossible to merge them. Furthermore, copying
the material in the scope of might into the scope of would doesn't give an
acceptable result either, for then we obtain a reading which says, in effect,
that in some sense of 'necessary', it is necessary that there will be a thief that