Yet how clear-cut is the distinction between the first and the second, or even between the first and the third, categories of premiss? To put it another way: might not a proposition which Galen defines as proceeding directly from the essence of the subject, that is to say, presumably, as evident to reason, from a different perspective be defined as dialectical or indeed rhetorical? To take Galen’s clearest specific example in PHP, that the hēgemonikon is the source of perception and voluntary motion, the only explicit grounds given for accepting it are that it is accepted universally, even by Galen’s opponents (II.3, 110). This, one might think, would put it in the category of endoxon; or at least, it is difficult to see on what grounds Galen might be able to advance the distinction between endoxic propositions and irrefutably self-evident ones. To put it simply, at a certain point arguments from consensus seem to be involved in the justification of propositions as “evident to reason”.