To explicate their notion of illocutionary commitment, these authors invoke their definition of illocutionary force in terms of the seven values mentioned in Section 2.3 above. On the basis of this definition, they define two notions pertinent to entailment relations among speech acts, namely strong illocutionary commitment and weak illocutionary commitment. According to the former definition, an illocutionary act S1 commits a speaker to another illocutionary act S2 iff it is not possible to perform S1 without performing S2. Whether that relation holds between a pair of illocutionary acts depends on the particular septuples with which they are identified. Thus suppose that S1 is identical with &lt;IP1, Str1, Mode1, Cont1, Prep 1, Sinc1, Stresinc1&gt; (corresponding to illocutionary point, strength, mode of achievement, propositional content, preparatory condition, sincerity condition, and strength of sincerity condition, respectively); and suppose that S2 is identical with &lt;IP1, Str2, Mode1, Cont1, Prep1, Sinc1, Stresinc1&gt;. Suppose further that Str1 and Str2 differ only in that 1 is stronger than 2. Then it will not be possible to perform S1 without performing S2; whence the former strongly illocutionarily implies the latter. (This definition of strong illocutionary commitment generalizes in a straightforward way to the case in which a set of speech acts S1, …, Sn−1 implies a speech act Sn.)