Charles Lassiter is a brilliant scholar studying Grice at Fordham

From his website:

"Grice’s theory of implicature is a framework aimed at spelling out what it means for an utterer to communicate something but not explicitly convey it."

"Consider a case in which A asks B where to get some gas and B replies,

There’s a garage around the corner.’

B has not explicitly conveyed that A can get some petrol there, but B has nonetheless communicated, or as Grice would prefer, meant, it.

This, in Gricean terminology, is an implicatum.

The addressee is supposed to move from the literal content of the utterance to the implicature through a kind of calculation process using conversational maxims.

Conversational maxims, which include injunctions like

‘don’t bother to say what you know to be false’ and
‘be relevant.’

and Speranza's favourite, "Avoid unnecessary prolixity" (sic): be brief.

a submaxim of Speranza's favourite maxim, "Be perspicuous (sic)!" -- i.e. be clear.

"Conversational maxims are the rules by which addressees figure out what utterers implicate.

"The Standard Model is that implicature calculation is something that happens entirely internal to the addressee.

The utterer’s utterance, along with contextual factors, is inputted into the hearer and the hearer’s private mental machinations calculate what the speaker implicated.

On this picture, the rules by which a hearer figures out an utterance are private.

Only the hearer has access to them because they are the hearer’s mental processes.

But, if this picture is right, then no one communicator has reason to think that anyone else shares the same rules governing those mental calculations.

But, mutual knowledge of the rules is needed for communication to get off the ground.

If A has no reason to think that B understands you can get gas at the station around the corner by an utterance of ‘there’s a station around the corner,’ then it seems doubtful that A genuinely communicates anything to B.

B just happens to make a lucky guess that A means you can get gas at the station around the corner by an utterance of ‘there’s a station around the corner.’

Lassiter then proposes that rules governing implicature calculation be made public.

That is, the rules are not privately represented in a communicative agent’s head.

Rather, the rules are out in the open for everyone to see.

This requires thinking about mental processes as public rather than private.

Mental processes do not happen purely inside the head—they are body- and world-involving.

Implicature calculation, then, is a mental process that incorporates the joint, dynamic activity of brain, body, and world."

--- or not, as Speranza is wont of saying.