Semantics

74 BASIC SEMANTICS
Saeed also touches the problem of the different ways of approaching
the issue of defining meaning and how this influences other problems
such as the difference between entailment and presupposition. He takes
two approaches to presupposition.
In the first approach, closely related to the philosophical tradition in
the line of Frege, Russell, Wittgenstein etc, sentences are viewed as external
objects where we don’t worry too much about the process of producing
them, or the individuality of the speaker or writer and their context
or their audience. Meaning is seen as an attribute of sentences rather
than something construed by the participants. Semantics, then consists of
relating a sentence-object to other sentence-objects and to the world.
As above mentioned, another approach, also discussed by Saeed,
views sentences as the utterances of individuals engaged in a communication
act, where the aim is to identify the strategies that speakers and
hearers use to communicate with one another. Then communication is
seen from the speaker’s viewpoint and we talk about presupposition as
part of the task of packaging an utterance; or we adopt the listener’s
viewpoint and see presupposition as one of a number of inferences the listener
might make on the basis of what the speaker has just said. Saeed
then discusses the following example:
i(i) John’s brother has just got back from Nigeria
(ii) John has a brother
and analyzes it as a truth relation in the following terms:
Step 1: if p ( the presupposing sentence) is true then q ( the presupposed
sentence) is true
Step 2: if p is false, the q is still true
Step 3: if q is true, p could be either true or false
and produces a first truth table for presupposition
p
q
T → T
F → T
T or F ← T
discussing the table as follows: If it is true that John’s brother has just
come back from Nigeria, it must be true that John has a brother. Similarly,
if it is false that John’s brother has come back from Nigeria ( if he’s still
there, for example), the presupposition that John has a brother still holds.