The Gricean mentalistic tradition rests on three basic related assumptions.[2]
The first is the assumption that the complete process whereby an addressee contributes to the full success of a speaker’s communicative act should be decomposed into two separable psychological sub-processes: a process of understanding (or comprehension) of the speaker’s utterance and a process of acceptance, which in turn can be construed as the addressee’s acquiring either a new belief or a new desire for action (depending on the direction of fit of the speaker’s utterance). I’ll call this the separability thesis.
The Gricean mentalistic tradition also rests on the assumption that verbal understanding is an exercise in mindreading, whereby the addressee recognizes the complex psychological state that underlies the speaker’s communicative act. I’ll call this the mindreading thesis. (Clearly, the mindreading thesis is presupposed or entailed by the separability thesis.)
Third, the Gricean mentalistic tradition further rests on a fundamental hypothesized asymmetry between what is required for understanding instrumental non-communicative agency and communicative agency. An agent intends her instrumental action to satisfy her desire in light of her belief, and the desirable outcome of her instrumental action can be recognized even if the agent fails to fulfil her goal or intention. But the intended effect of a speaker’s communicative action, which is the addressee’s understanding of what she means, cannot be achieved unless the speaker’s intention to achieve this effect is recognized (cf. Sperber 2000, p. 130). Unlike purely instrumental agency, communicative agency is ostensive in the following sense. A speaker’s communicative act is ostensive because its desirable outcome cannot be identified unless the addressee recognizes what the speaker intends to make manifest to him, i.e., what Sperber & Wilson (1986) call the speaker’s informative intention. Thus, the Gricean tradition rests on the thesis of the ostensive nature of communicative agency (Sperber & Wilson 1986).
On the picture of pragmatics which is part of the Gricean tradition of the past forty years broadly conceived, a human agent could not achieve a verbal or non-verbal act of intentional communication unless she had a complex psychological state, which Grice (1957) called the “speaker’s meaning” and which he construed as a set of three interrelated intentions.[3] First of all, by producing an utterance (or any other piece of ostensive communicative behavior), the speaker must have the basic intention (i) to act on her addressee’s mind, i.e., to cause him to acquire a new belief or a new desire (or intention) to perform some action. Second, the speaker must intend (ii) her addressee to recognize the content of her basic intention. Third, she must further intend (iii) her addressee’s recognition of her basic intention (in accordance with (ii)) to play a major role in his fulfilling her basic intention (i).
In the following, I will adopt (Sperber & Wilson’s (1986) simplified two-tiered account, according to which a communicative agent who produces an utterance has two (not three) interrelated intentions: an informative and a communicative intention, the first of which is nested within the other. She has the informative intention to make some state of affairs manifest to her addressee and also the further communicative intention to make her informative intention manifest to her addressee. So in this framework, the speaker’s communicative intention is fulfilled by the addressee as soon as the latter recognizes (or understands) which state of affairs it is the speaker’s informative intention to make manifest. But more is required for the speaker’s informative intention to be fulfilled: the addressee must further accept the speaker’s epistemic or practical authority. Depending on the direction of fit of the speaker’s utterance, the addressee must either believe the fact which it is the speaker’s informative intention to make manifest to him, or he must acquire the desire to act so as to turn into a fact the possible state of affairs which it is the speaker’s informative intention to make manifest to him.
In a nutshell, much of (Sperber & Wilson’s (1986) relevance-based framework rests on their insightful recognition that, on the broad Gricean picture of the speaker’s meaning, the task of the addressee can be usefully divided into two basic psychological processes: one is the process whereby the addressee understands (or recognizes) the speaker’s informative intention and the other is the process whereby he fulfils the speaker’s informative intention. The first process involves the addressee’s recognition of the speaker’s informative intention, whereby the addressee fulfils the speaker’s communicative intention that he recognize the speaker’s informative intention. By recognizing the speaker’s informative intention, the addressee comes automatically to both fulfil the speaker’s communicative intention and to understand (or comprehend) the speaker’s utterance. But for the addressee to recognize the speaker’s informative intention is not ipso facto to fulfil it. So the second process needed for the success of the speaker’s communicative act involves the addressee’s fulfilment of the speaker’s informative intention, whereby the addressee either accepts a new belief (in accordance with the content of the speaker’s assertion) or forms a new desire to act (in accordance with the content of the speaker’s request; cf. Jacob 2011).
While the relevance-based account of communication clearly presupposes the mindreading thesis, Sperber (2001) has offered further support in favor of the separability thesis. Following Krebs & Dawkins (1984), Sperber (2001) has argued that for cooperative communication to stabilize in human evolution, it must be advantageous to both senders and receivers. Since the interests of speakers and hearers are not identical, the cooperation required for the stabilization of communication is vulnerable to deception. When her utterance is descriptive, the speaker can speak either truthfully or untruthfully. The addressee can either trust the speaker or not. The speaker is better off if her addressee trusts her and worse off if he distrusts her, whether or not the speaker is truthful. If the addressee trusts the speaker, then he is better off if the speaker is truthful and worse off if the speaker is not truthful, while the addressee remains unaffected if he distrusts the speaker.
Clearly, not every speaker is (or should be) granted equal epistemic or practical authority on any topic by every addressee. As Sperber et al. (2010) have further argued, given the risks of deception, it is likely that human cooperative communication would not have stabilized in human evolution unless humans had evolved mechanisms of epistemic vigilance, whereby they filter the reliability of descriptive utterances. Focusing on a speaker’s assertions at the expense of her requests, a speaker’s epistemic authority depends to a large extent on the addressee’s evaluation of her reliability (or trustworthiness), which in turn depends jointly on the addressee’s evaluation of the speaker’s competence on the topic at hand and on the addressee’s representation of how benevolent are the speaker’s intentions towards him. According to Sperber et al. (2010), an addressee’s epistemic vigilance can apply to either or both the source of the information being communicated and its content.