Introduction: Demonstration and Science

In the first book of Posterior Analytics (An. Po.), Aristotle develops the notion of a kind of deductive argument he terms ἀποδείξις (apodeixis), or “demonstration,” in conjunction with a theory about science and scientific knowledge. Aristotle defines apodeixis as “a deduction productive of scientific knowledge” (An. Po. 71b17–18), immediately explaining that such a deduction enables us to know something by grasping it (71b18–19). Later on in the book, he clarifies the nature of apodeixis in relation to its characteristic of giving “an explanation and the reason why” of a thing (85b23–24). This kind of deduction has the possibility of providing genuine scientific knowledge, or ἐπιστήμη (epistēmē), in part, because its premises ultimately refer to τὰ πράγματα (ta pragmata), or “things,” in the sense of extra-linguistic entities. For Aristotle, this is because when we possess scientific understanding, we grasp that which relates a pragma with its cause (cf. 71b10–12). We might add that scientific understanding (epistēmē) is knowledge that consists in knowing the causal explanation of a thing, and knowing it holds necessarily. On this version of scientific realism, what we grasp in scientific knowledge is that which holds true about extra-linguistic things, their natures, causes, and properties, where truth does not merely pertain to propositions or words and their meanings. In addition to defining the cognitive state, Aristotle maintains that the discipline of science (any special science) depends on three kinds of parts: the essential attributes of the genus being studied, the common axioms of demonstration, and the non-essential attributes of the genus (cf. 76b11–16).