 What Aristotle means by this term is notoriously unclear; indeed there is some debate about whether he uses it consistently (Ross 1949: 50; Harari 2004: 33–34). But it is possible to make some general comments. Aristotle customarily distinguishes induction from syllogistic reasoning, in the sense of demonstration. As he writes in one place, “all our beliefs come either through demonstration [dia sullogismou] or from induction [ex epagōgēs]” (APr. 68b13). The general contrast here is that while “demonstration proceeds from universals to particulars,” induction takes one “from particulars to universals” (Ross 1949: 47; cf. Top. 195a13–14). The latter, of course, is precisely what is required to discover the principles of scientific explanation. What is unclear, however, is how we can move from particulars to universals.