Robert Mueller and Conversational Implicature

There is an important difference between what is said and what is implicated.

Posted May 30, 2019

On May 29, in a rare public statement, Special Counsel Robert Mueller made a number of claims, that were interpreted very differently by the different political camps. And the philosophy and psychology of language processing in communication could help us to understand what was going on.

Among other things, Mueller said that  "if we had had confidence that the president clearly did not commit a crime we would have said so". And also: "the Constitution requires a process other than the criminal justice system to formally accuse a sitting president of wrongdoing," But what do these claims mean? Total exoneration or impeachment referral? 

The starting point of the philosophical and psychological literature on language processing in communication is that what we say can be very different from what is implicated. The classic example is that when an academic letter of recommendation praises the candidate's handwriting (and does little else), the letter does not say anything negative about the candidate, but what is implicated is something very negative indeed, something like: the only thing that can be praised is the candidate's handwriting. Way more is implicated than what is, strictly speaking, said. 

More generally, when we have a conversation, we assume that the others observe what the British philosopher Paul Grice calls the ‘Cooperative Principle’. Very simply, we assume that the speaker is also trying to have a conversation. We assume that the speaker is trying to be understood. When the Cooperative Principle appears to be violated, we are looking for ways to interpret the speaker’s sentences in such a way that would make sense and make the speaker appear to respect the Cooperative Principle. As Grice says,

The hearer is faced with a minor problem: How can [the speaker’s] saying what he did say be reconciled with the supposition that he is observing the overall Cooperative Principle? This situation is one that characteristically gives rise to a conversational implicature.

The hearer tries to reconcile what the speaker says with the Cooperative Principle by asking themselves what the speaker could have meant that would not violate the Cooperative Principle. And this directs their attention to what the speaker may have wanted the hearer to think.

In the case of the letter of recommendation, it does not seem to be very cooperative in a recommendation letter to praise the handwriting of the candidate. What is going on then? How can this letter be read in such a way that the letter writer doesn't come across as just blatantly not doing their job? The only interpretation consistent with the Cooperative Principle is that the letter writer has a very negative opinion of the candidate. This is an example of conversational implicature. The letter says that the candidate's handwriting is good. And that is all that it says. But it has a conversational implicature that the candidate is no good. 

With this apparatus in hand, let's return to Mueller's statements.

Exhibit A: "if we had had confidence that the president clearly did not commit a crime we would have said so." What is said is a somewhat complicated conditional claim. But what is implicated? How could we interpret this in a way that would not go against the Cooperative Principle? If we assume, as we should, that the Special Counsel did indeed want to communicate something here, the obvious interpretation is that he does not have the confidence that the president clearly did not commit a crime. Does this imply that the president did indeed commit a crime? Strictly speaking, it does not. But if anyone could have the confidence that the president didn't commit a crime, it would have to be the Special Counsel who has spent months investigating the issue and who has just said that no further investigating is necessary. If his confidence that the president didn't commit a crime could be increased, he presumably would not have closed the investigation. All this is implicated, obviously, not said. But it is difficult to reconcile Mueller's claims with the Cooperative Principle without interpreting him as making exactly this conversational implicature. 

Exhibit B: "the Constitution requires a process other than the criminal justice system to formally accuse a sitting president of wrongdoing." What is said here is little more than a claim about the reach of the criminal justice system according to the Constitution. But what is implicated? How can we interpret this sentence in such a way that it does not just state something deliberately irrelevant? The only plausible interpretation I can see is that the Special Counsel said this in order to direct our attention to the process by means of which a sitting president can be formally accused of wrongdoing. And we all know what that process is...