In the final lecture (XII), Austin sets out to classify illocutionary acts in broad strokes. It’s time to systematize “illocutionary force” — the function a warning, an order, a promise performs — which the previous article left as an open question. The overview article gave only the conclusion; here we read how tentatively he actually arrived at it.

Starting from several thousand words

Gathering the raw material was brute-force work. Using the simple test of the first-person-singular present-indicative active form, and working through a concise dictionary “in a liberal spirit,” Austin says, you get a list of verbs “of the order of the third power of 10.” Why say “the third power of 10” instead of “1,000” or “about 1,000”? Austin can’t resist a joke in his own footnote — “first, it looks impressive and scientific; second, because it goes from 1,000 to 9,999 — a good margin — whereas the other might be taken to mean ‘about 1,000’ — too narrow a margin.” Pulling five broad families out of these several thousand verbs is the work of the final lecture.

The five classes, defined

I distinguish five more general classes … by the following more-or-less rebarbative names: (1) Verdictives. (2) Exercitives. (3) Commissives. (4) Behabitives (a shocker this). (5) Expositives.

(Japanese and English renderings of quotations throughout are ToL’s own.) Let’s take them one at a time, in Austin’s own words.

Verdictive giving a verdict estimating Exercitive appointing ordering, warning Commissive promising declaring intent Behabitive apologizing cursing, challenging Expositive arguing illustrating verdictive = exercise of judgment exercitive = exercise of influence commissive = assuming an obligation behabitive = adopting an attitude expositive = clarifying reasons and arguments Austin himself: "the last two are the most troublesome — behabitives too miscellaneous, expositives too numerous and seemingly overlapping every other class"
The five classes of illocutionary act, with typical examples. Diagram: ToL

Austin’s own candid doubts

Having laid out the classification, Austin doesn’t hide its limits. He admits outright that the last two classes — behabitives and expositives — are “the most troublesome,” and that the classification itself might not be clear, might be cross-classified, or might need reworking altogether. Behabitives trouble him because they seem too miscellaneous; expositives because they are so enormously numerous that they seem to overlap every other class while somehow still being unique — in a way, he confesses, he hasn’t managed to make clear even to himself.

Near the end of the final lecture, he compresses the five into a single sentence each:

To sum up, we may say that the verdictive is an exercise of judgment, the exercitive is an assertion of influence or exercising of power, the commissive is an assuming of an obligation or declaring of an intention, the behabitive is the adopting of an attitude, and the expositive is the clarifying of reasons, arguments, and communications.

And he closes the lectures themselves this way:

I have as usual failed to leave enough time in which to say why what I have said is interesting. … I should certainly like to say that nowhere could, to me, be a nicer place to lecture in than Harvard.

He doesn’t hide that the classification is unfinished — and ends on that note of candor and lightness anyway. That combination is what gives this book, assembled from a dead man’s lecture notes, its final aftertaste.

Looked at this way, the five classes read less like a finished set of shelves than a draft Austin himself flagged as unfinished — which is exactly what left room for those who came after him to keep building.

After the five classes

Austin’s student John Searle critically re-examined this five-way split in Speech Acts (1969) and reworked it into his own five categories, including declarations and directives. Given that Austin himself had already admitted “the last two are the most troublesome,” Searle’s revision reads less like a correction than a continuation of the candid uncertainty Austin left behind.