 There must, however, exist a science whose aim is to discover and teach the method of how to investigate, through correct reasoning, what is not known from what is known. It cannot be metaphysics because this science regards things apart from motion. A syllogism, however, is a kind of motion where the properties are deduced from the subject(-matter) and the conclusion from the premises (NLP prologue, 4). That science is logic. Since logic has the task of discovering a method of knowing that can be used by all sciences (LPA prologue), logic is thought of as the modus scientiarum, or the science of sciences (scientia scientiarum). Proficiency in the way of reasoning allows for the discovery of truth in every field of inquiry (DOS 419), even though every science demonstrates according to the possibilities of its matter (NLP II.34, 512). In order to accomplish this task, logic needs to teach how to combine one term with another (or divide one from another), the species of combinations and divisions corresponding to the species of propositions or statements (DOS 517). Logic also relates things to one another by means of a middle term in the syllogism, which is logic’s subject matter.