 Students of speech acts contend, as we have seen, that the unit of communicative significance is the Illocution rather than the Proposition. This attitude prompts the question whether logic itself might be enriched by incorporating inferential relations among speech acts rather than just inferential relations among Propositions. Just as two event-types E1 and E2 (such as running quickly and running) could be logically related to one another in that it is not possible for one to occur without the other; so too speech act types S1 and S2 could be inferentially related to one another if it is not possible to perform one without performing the other. A warning that the bull is about to charge is also an assertion that the bull is about to charge but the converse is not true. This is in spite of the fact that these two speech acts have the same propositional content: That the bull is about to charge. If, therefore, warning implies asserting but not vice versa, then that inferential relation is not to be caught within the net of inferential relations among propositions.