The internal semantics of a verb reflects the meaning expressed by the verb itself. This includes specification of the verb's semantic arguments and all of the relations involving these arguments: the roles they play, and any events/subevents which are entailed by the verb. This structure corresponds at the word level to a semantic relation in the sort hierarchy rooted at situation.
The external semantics reflects meaning particular to a particular situation expressed by the verb on a particular use. Examples of elements of external semantics include location, time, and thematic information (contributed to a situation by thematic adjuncts). The latter might include purpose clauses and temporal adverbial phrases like frequentatives and duratives. These elements derive from explicit components of sentences, and therefore can be considered part of the truth-conditional meaning of these sentences, in contrast to information in the background conditions of the sentences which reflect presuppositions or conventional implicatures not directly contributed through the meaning of phrases in the sentence. This information cannot therefore simply be pushed into the background.
This distinction allows us to identify and isolate the kinds of effects of modifying phrases can have on the interpretation of a sentence. Consider the sentence in d90.
This sentence can be interpreted in two ways. The preferred reading is that ``John seeing Mary'' event took place in the park, which entails that both John and Mary were in the park. Another available reading is that Mary was in the park, and John saw this, without indicating anything specific about John's location. This reading may actually be the preferred reading under certain circumstances, given world knowledge. This is the case for d91. We wouldn't want to say that the PP in this example is part of the complement noun phrase, due to the oddness of d96.
John saw Mary in the ladies' room. *Mary in the ladies' room was seen by John.
There is, however, no available reading for d90 which places John in the park and Mary somewhere outside of the park. So a locative phrase can be taken as restricting the location of an event as a whole, or of particular participants in the event (in this case, the direct object). Traditional treatments of locative adverbials (e.g. Davidson davidson:67) would only account for the located-event reading, as they are only associated with event variables. Introducing a distinction between internal semantics and external (situational) semantics opens up the possibility of an analysis where the adverbial is interpreted as either an external (event-oriented) modifier, or an internal (participant-oriented) modifier (see also Johnston 1994 for discussion of the event- vs. participant- orientation of purpose clauses). The distinct readings can be predicted through an ambiguity in the compositional semantics rather than through complex inferencing: the locative can modify either the event index, or pick out individuals from the internal semantics.
Another example for which this internal/external modification ambiguity holds is found in d92.
The mouse ran under the table.
This sentence has three available readings: either the ``mouse running'' event is located underneath the table, or the mouse ran along a path with its endpoint under the table, or the mouse ran along a trajectory which includes a point under the table. The first reading is an event-oriented reading of the locative, while the other two readings are both participant-oriented readings (in Davis' terms, the mouse is fig and the path is grnd in a mot-rel). The two participant-oriented readings stem from ambiguity of the preposition under.
I will return to these issues in Chapter 3, where I will explore more fully the status of modifying prepositional phrases. For the current purposes of defining a representation for verb semantics, however, the examples given here should suffice to justify the internal/external distinction I introduce. In Chapter 3, we will see how this distinction can lead to a solution for the modification ambiguities presented here.