Page 401 - Encyclopedia of Philosophy of Language

types and INVOLVES is a primitive binary relation between situation-types. Infons of this form are called (unconditional) constraints. However, constraints by themselves do not constrain reality. The factuality of an infon «JNVOLVES, S, S'; 1» as such is no guarantee that situations of type 5 ' always come along with situations of type 5. It is only in structures of situ- ations that constraints correspond to regularities between situations. Structures of situations are models of reality. In keeping with the slogan 'Reality consists of situations—individuals having properties and standing in relations at various spatiotemporal locations' (S&A: 7), a 'structure of situations' M is a collection of abstract situations, i.e.,a collection of sets of infons. M consists of a collection, M, of factual situations, with a nonempty subcollection, A/0, of actual situations. It observes four conditions:
(a) every s in M is coherent;
(b) if seM0 and s'^s, then s'eM;
(c) if X is a subset (with stress on set) of M, then
thereisanseM0suchthat\JX^s(\JXisthe set of infons / for which there is an seX such that fes);
(d) if C is a constraint in M, then M respects C. Condition (a) states that reality is consistent. Con- dition (b) models the fact that parts of real (actual) situations are also (factual) situations. Condition (c) requires that the infons involved in a 'set' of factual situations be also members of an actual situation. Recall that M0 was defined as a 'collection' of abstract situations, so it need not be a set—it could be a proper class: too large to be countenanced as a set. But if M0 actually were a set, then (c) would entail the existence of a situation seM0 such that (JM0^s, so Vs'eM0:s'^s. Such a situation, if present, might be called a world in M.
Condition (d) relates constraints to the regularities in reality that underlie the possibility of extracting information about situations from other situations. Intuitively, if constraints are conceived of as laws, what this clause says is that reality behaves in con- formitywiththelawsitcontains.Therelevantnotion of a structure of situations M respecting such a con- straint is therefore defined as follows: M respects «INVOLVES,S,S';1» iff VseM0;3s'eM: V/: i f / i s an anchor for exactly the indeterminates of S, and S[f]^s, then 3g: (S'[f])\g]^s'. This says that for every situation of type 5 there is a situation s' of type 5 ' such that all ways of anchoring S in s are ways of (partially) anchoring S' in s'.
Notice that S and 5' are arbitrary situation-types, so 5" can contain indeterminates absent from S. In Barwise and Perry (1983:146), this is considered 'a mistake.' Accordingly, Barwise (1989: 114) simply stipulates that every parameter in 5 ' will also be a parameter in S. This enables us to simplify the defi- nition considerably: M respects « INVOLVES, S,S';IJ> iff VseM0:3s'eM:Vf: if S[f]^s, then S'[f]^s'. For
example, the constraint «INVOLVES, {«SMOKE,/; !»},
Having defined the notion 'M respects C,' what the interpretation of situations is given a certaincon- straint can be defined. The 'interpretation' of a situ- ation s of type S with respect to a constraint C, [s]c, where C=^INVOLVES, 5,5'; 1», is the collection of situations s' such that V/: if / anchors exactly the indeterminates of S and S[f\^s, then s' is of type
Sin-
So, for C= {((INVOLVES, {{SMOKE, /;!»}, {«F«E, /;
!»}; 1»> and s={«SMOKE, here&now, !>>}, [s]c is the collection of all situations s' such that {<£FTRE, here&now; l»}e.s'. In other words, the interpre- tationwithrespecttoCofasituationwithsmoke here and now consists of involved situations with fire here and now.
3. Situation Semantics
Assuming that linguistic meanings of expressions are conventional constraints on utterances and that the primary function of language is to convey infor- mation, situation semantics describes the meaning of an assertively used indicative sentence 0 as a relation u[4>]s between situations u in which </>is uttered and situations s described by such utterances. This is called 'the relational theory of meaning.' In other semantic approaches,theconstraints<£putsonuhavebeenput away in so-called 'context sequences.' Within situation semantics, the context of a sentence is the same type of thing as the thing the sentence is about, which allows an account of the 'efficiency of language' alluded to above.
An utterance situation u comprises the utterance of an expression 0 (an aspect of u which is made explicit inthenotation'u[(f>]s'weuse)byonespeakertoone addressee at one location. Moreover, u determines a number of 'speaker connections,' which specify the referents the speaker intends to denote by uttering certain subexpressions of 0. For instance, they specify the intended referents of proper names and the(tem- poral) locations that serve as intended referents of tenses of verbs.
The 'meanings' of lexical and compound expressions exploit these features of u. For example, a sentence like 'I am stroking Jackie' is assigned the meaning u[I am stroking Jackie]s iff ^STRO- KE, I, a, b', 1 ~%>es, where / = u(ani), I temporally overlaps with the location of u, a is the speaker in u, and b = u(Jackie). The interpretation of coordinated sen- tences is straightforward: u[(f> and i//]s iff u[<f>]s and u[\l/]s; u[(f> or \j/]s iff u[4>]s or u[i//]s.
Situation Semantics
respected by M iff {«SMOKE,/;!»}[/] c j , then
{ « F « E , / ; ! » } ; ! » is
VseM0:3s'eM:Vf: if
(«FKF.,/;!»}[/]£/. This amounts to VseMo: 3-s'eM: V/: if {«SMOKE, /; 1»} s * , then {«FIRE, /;!»}£.?'.So,foreverysituation5inM0 withsmoke at a number of locations, there is a situation s' in M with fire at those locations.
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