 The sciences of speech divide into those that are significative of what is known (grammar) and those that are inquisitive about what is not known (logic and rhetoric) (DOS 468). Rhetoric differs from logic in that the former is about hypotheses and what is particular, whereas the latter is about theses and what is universal—its subject matter is the syllogism and its species (DOS 468; 471; 474). By contrast, rhetoric, as the science of speaking well, presupposes grammar—the science of signifying correctly (DOS 629). The subject matter of grammar is significative speech qua significative (DOS 474), that is, the oratio and its parts insofar as they signify or co-signify (DOS 489). Speech (sermo) here means the human vox as it signifies by convention (ad placitum) (DOS 488). Grammar considers the sentence from the point of view of how well it is formed or its congruity (congruitas), which is the result of how its elements are correctly ordered to one another, rather than of the correspondence of those words with the things they signify (NSLPery I.5). The end (finis) is to teach how to correctly express the conceptions of the mind (DOS 483–84; 490). Kilwardby’s willingness to grant a scientific role to grammar is notorious (Rosier 1994; Sirridge 1988).