Section 7-5 SENTENCE INTERPRETATION
| A number of rules of interpretation appeared in the last chapter.
The linguist designed those particular rules to describe the interpretation of certain kinds of sentences analyzed syntactically.
The rules gave interpretations for declarative, performative, imperative, and interrogative sentences
as referring to propositions having characteristic defining semasiological patterns. |
|
Consider further the sentence “This is John and this is Mary, but this is Bill” as diagramed in figure 3.
It consists syntactically in three independent clauses, which clauses, CL1, CL2, and CL3, so happen to have the same type of interpretive structure. |
[+Declarative]CL1  r CAUSE(s,PERCEIVE1(h,TRUE(x))) |
| [+Declarative]CL2 r CAUSE(s,PERCEIVE1(h,TRUE(y))) |
| [+Declarative]CL3 r CAUSE(s,PERCEIVE1(h,TRUE(z))) |
| Many features of the sentence are ultimately derived from a combination of other features and syntactic patterns.
The simplest features arise on terminal constituents.
The tree is a semasiological map of how the interpretation is inherited by phrase structures.
An example is to show how S3 inherits the interpretation of CL3. |
| [+Declarative]S3 [+Declarative]CL3 |
| [+Declarative]S3 r CAUSE(s,PERCEIVE1(h,TRUE(z))) |
|
There are a number of words in English that traditionally belong to the class of conjunction, which class we rename to grammatical connective (C).
The motivation is that logical conjunction is just one meaning possible for this class of the “conjunctions.” One connective is illustrated in the compound sentence under investigation — but, the meaning of which is adversative.
The other “conjunction” illustrated, and, is not.
Yet both these words include the logical meaning of the conjunctive operator AND( ).
It appears that this terminal constituent, the connective, has at least the following features: |
| [+Conjunctive]C | (for and, but) |
| [+Adversative]C | (for but) |
|
Linguists express the subcategorization of properties in terms of features by the use of segment structure rules.
We described in ¶5-5-5 how features are designated and interpreted in a GT-grammar.
One convention for writing semasiological segment structure rules is as shown in box 7.
Each segment has a category, which in (2), (3) and (4) are the same.
The segment in (4) is the result of a special operation on (2) and (3) defined as follows:
Use all features in the initial segment except: for each feature specified in both segments give the resulting segment the Boolean value of the one in (3),
then add any features in (3) that are not specified in (2). |
|
Originally this kind of rule was restricted to the terminal constituents of phrase structure.
It is much more useful to make them available to all constituents as described in box 7.
The rules may have the force of subcategorizing the constituent syntactically.
This means that the syntactic environment, i.e., the category, may be carried with the segment as features.
When the constituent is terminal, its subcategorization is called “strict” subcategorization.
The rules may also impose a subclassification on the category.
These rules describe, more or less, the actual semantics imposed by the language on the words and word patterns.
The specification of the possible features of a category is called its ontology.
|
| To make use of this device for the part of speech that we call a connective (conjunction), there are rules like those in figure 5: |
| The double arrow helps to keep this kind of rule distinct from the phrase structure rule.
Notice that the features in the second rule are discrete, i.e. individually distinct and mutually exclusive.
These are alternatively expressed as having Boolean values, either present or absent.
Sometimes they are each assigned a number on a scale naming the whole set of features.
The semanticist may write a rule of interpretation for each separate connective to relate it to its appropriate semasiological structure.
For example: |
| [+Conjunctive]C reference(C) = AND( ) |
|
There cannot be one rule to describe the interpretation of all sentences containing a connective.
The interpretation of the connective relates to the interpretation of the syntactic structures in which it is found.
In the case of the Clause appearing in [P2] one needs to express the fact that the arguments of the relation AND( ),
which is a two-place predicate, are the content of the preceding Clause and the subsequent Clause.
To do this we may enlist the services of a transformation.
In the excursus to chapter 5, CONJ appeared as a rule of derivation in a GT-grammar of the predicate calculus: |
| CONJUNCTION (CONJ) |
|---|
| base1: | P1 |
| base2: | P2 |
| transform: | AND(P1,P2) |
| To keep things simple we will want to build our rule for grammatical conjunction on the same pattern.
In the following transformations I do two things:
1) place the bases to the left as a single phrase structure, with the transformed phrase structure to the right, and
2) extend the relevant components using a broad line to its respective semantic interpretation in the predicate calculus. |
| This means that the content of the superordinate clause is to be interpreted as the logical conjunction of the content of the clause preceding and the clause following the grammatical conjunction.
As a consequence of certain transformations, some of the syntactic structure generated by rules may be reduced.
This is always done to bring the syntax of the output sentence into conformity with the logical structure of the sentence. |
| Whenever possible my intent is to use MultiNet as a explicit way to describe the semantics of a sentence.
The designers of this system, however, desired to represent knowledge, without full attention to syntactic constraints on its expression.
Their idea was to keep things simple by omitting explicit mention of grammatical conjunction.
Usually conjunction at the metalanguage level is simply interpreted as the inverted vee of the predicate calculus.
Every assertion is simply the conjunction of all the atomic elements going into making up its meaning.
Whenever conjunction is explicitly mentioned, it is the use of the enumerator functor for the members of a set: *ITMS.
If the members of the set are to be ordered, the tuple functor is used: *TUPL. |
|
The linguist may describe the interpretation of but in a similar manner.
This rule requires an additional statement of the adversative relationship that holds between the two propositions conjoined.
An adversative relationship means that the propositions asserted describe situations that are usually opposed.
One way to model this relationship formally would refer to a fuzzy probability functor whose value lies between zero and one.
For example, “usual” is nowadays interpreted as around 80% probable (Hakel, 1968).
Presumably the conjunction but would be appropriate whenever the probability of the exclusive relationship holding is greater than half. |
| USUAL(x) probability(x) = 0.8 |
| PROBABLE(x) probability(x) > 0.5 |
| POSSIBLE(x) probability(x) > 0.0 |
| To use MultiNet to describe the semantics of the adversative conjunction, we must make some of the same observations.
What happens in many cases is that a relation is defined without regard to its possible atomic status.
For the adversative generally MultiNet uses opposition (OPPOS (x, y) and does not attribute a measurement to probability.
Probability is designated explicitly as adverbial to the sentence, which in English is semantically a property of a situation.
To express what we have, we would use the *ITMS functor and specialize the MODAL relation to the class of items relating to probability.
The meaning of EXCLUSIVE is expressed using the functor *VEL (exclusive disjunction). |
| *ITMS(x, y)  MODL(s, probable) s = *VEL(x, y) |
|
The interpretation of the conjunction of the clauses in the sentence “This is John and this is Mary, but this is Bill” continues with reference to the PS in figure 3.
This is diagramed on the phrase structure (PS) map: |
| PS1: | [ ]CL11 [ CL111 [+Conjunctive]C11 CL112]CL11 |
by P2 and S1 |
| [ ]CL111 r y |
|
| [ ]CL112 r z |
|
| PS2: | [+Conjunctive]CL11 r AND(y,z) |
from PS1 by Conj(CL) |
| PS3: | [ ]CL1 [ [ CL11 [+Adversative]C1 CL12]CL1 |
by P2, S1, S2 |
| [ ]CL11 r AND(y,z) |
|
| [ ]CL12 r x |
|
| PS4: | [+Adversative]CL1 r AND(AND(y,z),x) PROBABLE(EXCLUSIVE(AND(y,z),x)) |
| | from PS3 by Advers(CL) |
| Finally, the feature [+Declarative]S1 receives its standard interpretation presumably by the clause not being marked as of any other mode. |
| PS5: | [ ]S1 CL1 |
by P1 |
| PS6: |
| [+Declarative]S1r CAUSE(s,PERCEIVE1(h,TRUE(AND(AND(y,z),x) PROBABLE(EXCLUSIVE(AND(y,z),x))))) |
| from PS4 by Decl(S) |
![Conjunction of Clauses [Conj(CL)]](gif/ri/gramri01.gif)
![Adversative Conjunction of Clauses [Advers(CL)]](gif/ri/gramri14.gif)
