Think of such an act as being like a move in chess.
However, natural language may be full of exceptions (and so not at all like chess in this regard).
Still, Searle sides with Austin and against Wittgenstein, arguing that there are clear uses of language and these are finite in number. Clarity about what we are doing will reveal this.
Classifying illocutionary acts, we get a few basic kinds of acts (which can be combined):
We tell people how things are
We try to get people to do things
We commit ourselves to doing things
We express our feelings and attitudes
We bring about changes (through the utterances).
Example of necessary and sufficient conditions for promising:
S makes a promise T to the person H iff
1. Normal input-output conditions obtain
2. S expresses some proposition p in T
3. In expressing that p, S predicates a future act A of S.
4. H would prefer that S do A instead of not do A, and S believes that H would prefer this.
5. It is not obvious to both S and H that S will do A.
6. S intends to do A.
7. S intends that T will put S under obligation to do A.
8. S intends that H know that T is to count as obligating S to do A.
9. Semantic rules of both S and H are such that only if 1-8 obtain is there a promise.
Searle recombines these into:
Propositional content rule: The promise is uttered only in context of a sentence T which predicates some act A of S.
Preparatory rules: The promise is uttered only if H would prefer S's doing A and S believes H would prefer this; and if it is not obvious that S will do A.
Sincerity rule: The promise is uttered only if S intends to do A.
Essential rule: The promise counts as undertaking an obligation to do A.
Searle uses this as an example, and then extends this over into a preliminary analysis of other illocutionary acts.
Some open questions:
Searle's list looks pretty exhaustive - is Wittgenstein wrong that there are unlimited variations?
Does (should?) Searle give us reason to believe that declarative statements and illocutionary acts are very clearly distinct? Should we have Austin's worry?
What kind of meaning theory would well fit with what Searle is proposing?