Two people, Mary and Peter, recur throughout the book. They are standing by some wild strawberries. Let’s follow Mary’s behavior step by step.
Step 1: just eating
Mary picks and eats a wild strawberry while Peter watches. She eats it because it is edible. She tells no one anything. If Peter concludes “oh, they’re edible,” that was not Mary’s intention (p. 135).
Step 2: eating so he sees
Mary knows Peter is watching, and she wants him to believe the strawberries are edible. So she picks and eats one. Eating normally is enough to achieve her aim (pp. 135–136).
The book calls this an informative intention: an intention to change someone’s belief.
Step 3: wanting him to know she is communicating
Now one step further. Mary wants Peter to recognize not just the fact but that she is trying to tell him. Eating normally won’t do that: Peter may simply think “Mary is eating.”
So Mary eats in an obviously exaggerated way (p. 137). Seeing the exaggeration, Peter realizes “she is showing this to me.” This is the communicative intention: the intention that the other person recognize your informative intention.
What differs
| What reaches the other person | |
|---|---|
| Just eating | Strawberries are edible (Peter inferred it on his own) |
| Eating so he sees | Strawberries are edible (informative intention) |
| Eating in an exaggerated way | Strawberries are edible, and “I am telling you this now” (communicative intention) |
In the last step, the movement has no fixed meaning. Exaggerated eating counts as a sign of “I’m communicating” only because Peter infers Mary’s intention. That is the mechanism the book calls ostensive-inferential, as opposed to code (p. 140).
The book’s aim
The author argues that this last kind, showing that you communicate and letting the other infer, is barely seen outside humans and was the foundation on which language could arise (pp. 199–202). The next articles look at why, in detail.