The Logic of Consequence in Aristotle’s Biology

Two of Aristotle’s major legacies, namely, the theory of scientific syllogism and teleology seem to conflict on several planes. Indeed, an array of formal limitations prevents him from formalizing teleological explanations into scientific syllogisms, which are entirely absent from his works. To achieve this, Aristotle resorts to a different tool, the logic of ‘consequence’. This governs both the teleological relation between an end and a means that underlies necessity ‘from a hypothesis’—which is the necessity proper to living things—and a different form of syllogisms, namely, syllogisms ‘from a hypothesis’. His guidelines in the first chapter of his Parts of Animals on the proper form of demonstration to be adopted in biology should be read as laying out the rules of inference for translating teleological explanations into syllogisms ‘from a hypothesis’.