debt; or he would have failed to mend it, which would have amounted to a refusal or rejection. Mary avoids putting herself in his debt or meeting with a refusal by avoiding any modification of their mutual cognitive environment. If Peter mends the hair-drier, he is being kind on his own initiative, and she does not owe him anything. If Peter decides not to mend the hair-drier, he might reason as follows: she doesn’t know I know she intended to inform me of her wish, so if I ignore it, she will attribute this to her failure to inform me; she may find me stupid, but not unkind. As for Mary, she may have intentionally left this line of reason-ing open to Peter. If he does not mend her hair-drier, she will find him unkind, but not hostile. His failure to grant her wish will not be in the nature of a rebuff. They will stand in exactly the same social relationship to each other as before. This shows how ostensive communication may have social implications that other forms of information transmission do not. By making her informative intention mutually manifest, the communicator creates the following situation: it becomes mutually manifest that the fulfilment of her informative intention is, so to speak, in the hands of the audience. If the assumptions that she intends to make manifest to the audience become manifest, then she is successful; if the audience refuses to accept these assumptions as true or probably true, then she has failed in her informative intention. Suppose – we will soon see how this may happen – that the audience’s behaviour makes it mutu-ally manifest that the informative intention is fulfilled. Then the set of assump-tions I that the communicator intended to make manifest to the audience becomes, at least apparently, mutually manifest. We say ‘at least apparently’ because, if the communicator is not sincere and some of the assumptions in I are not manifest to her, then by our definition of mutual manifestness, these assumptions cannot be mutually manifest to her and others. A communicator is normally interested in knowing whether or not she has succeeded in fulfilling her informative intention, and this interest is mutually manifest to her and her audience. In face-to-face communication, the audience is generally expected to respond to this interest in fairly conventional ways. Often, for instance, the audience is expected to communicate its refusal to accept the information communicated, or else it becomes mutually manifest that the com-municator’s informative intention is fulfilled. Where communication is non-reciprocal, there are various possible situations to be taken into account. The communicator may be in a position of such author-ity over her audience that the success of her informative intention is mutually manifest in advance. Journalists, professors, religious or political leaders assume, alas often on good grounds, that what they communicate automatically becomes mutually manifest. When the communicator lacks that kind of authority, but still wants to establish a mutual cognitive environment with her audience, all she has to do is adapt her informative intentions to her credibility. For instance, in writ-ing this book we merely intend to make mutually manifest that we have devel-oped certain hypotheses and have done so on certain grounds. That is, we take it as mutually manifest that you will accept our authority on what we actually think. The mutual cognitive environment thus created is enough for us to go on