... identification of the intended referent, and in the case of the S[ action, the plan is simply to do nothing, because the referent of the term is already mutually known. This is not the case, because the ... whoever fits the description. Furthermore, the speaker assumes that the son is capable of identifying his own fa- ther on the basis of knowledge he already has; therefore the plan for the hearer ... precondition of the SI action is that the speaker and hearer mutually believe both the description in the noun phrase and the PF identifiable description. In the case of the NSI action, the speaker...