H. P. Grice, "Modal disimplicature"

 there is a corresponding distinction between two "uses" of ordinary indicatives; sometimes one is declaring or affirming that p, one's intention being primarily to get the hearer to think that the speaker thinks that p; while sometimes one is telling the hearer that p, that is to say, hoping to get him to think that p. It is true that in the case of indicatives, unlike that of volitives, there is no pair of devices which would ordinarily be thought of as mood-markers which serves to distinguish the sub-mood of an indicative sentence; the recognition of the sub-mood has to come from context, from the vocative use of the name of H, from the presence of a speech-act verb, or from a sentence-adverbial phrase (like "for

your information").