Unlimited continuous sensible magnitude

This chapter focuses on Anaximander’s apeiron, to which Aristotle explicitly applies the concept of συνεχές, not by chance. Indeed, among all the Ionian philosophers, Anaximander articulates the most sophisticated and ‘modern’ proposal of a principle that is a single sensible magnitude—and therefore, for Aristotle, continuous—yet infinitely extended. Aristotle’s demonstration applied to Anaximander’s apeiron, which cannot exist in a single infinitely extended magnitude, also refutes the other Ionian philosophers. However, Anaximander also provides Aristotle with an opportunity for comparison with Anaxagoras, Empedocles, and Democritus, both in terms of the infinity of his principle and the idea that the many are derived from this one by separation. This comparison allows Aristotle to interpret that even the so-called pluralist philosophers assumed a single principle at the origin of all things. The problem that arises is how the relationship between the one and the many in the realm of physical magnitudes was addressed by the philosophers who preceded Aristotle. According to Aristotle, all the Presocratics posited being, viewing it as one, ungenerated, incorruptible, immortal, and imperishable, as well as indefinite, limitless, and continuous—a description that can be found in an exact form in Parmenides’ fragment 8.