 Consequently, the construction of enthymemes is primarily a matter of deducing from accepted opinions (endoxa). Of course, it is also possible to use premises that are not commonly accepted by themselves, but can be derived from commonly accepted opinions; other premises are only accepted since the speaker is held to be credible; still other enthymemes are built from signs: see  §6.5.  That a deduction is made from accepted opinions—as opposed to deductions from first and true sentences or principles—is the defining feature of dialectical argumentation in the Aristotelian sense. Thus, the formulation of enthymemes is a matter of dialectic, and the dialectician has the competence that is needed for the construction of enthymemes. If enthymemes are a subclass of dialectical arguments, then it is natural to expect a specific difference by which one can tell enthymemes apart from all other kinds of dialectical arguments (traditionally, commentators regarded logical incompleteness as such a difference; for some objections against the traditional view, see  §6.4).  Nevertheless, this expectation is somehow misguided: The enthymeme is different from other kinds of dialectical arguments insofar as it is used in the rhetorical context of public speech (and rhetorical arguments are called ‘enthymemes’); thus, no further formal or qualitative differences are needed.