 To see why this is so, one may focus on a controversy about individuation which Popper sought to dissolve, by pointing out that it derived from a false opposition. This was a controversy begotten by a disagreement between Anscombe and Lukasiewicz regarding the principle of individuation in Aristotle (see Anscombe et al. 1953). Popper points out that their disagreement is only apparent, due to the fact that they are answering different questions: Lukasiewicz insists that form should be counted as the “source of individuality” because it explains how a thing with many parts is a single individual and not a plurality, it accounts for the unity of individuals. He has in mind questions like “How do all these bricks constitute a single house?” or “What makes this collection of flesh and bones Socrates?”, and here Aristotle does indeed appear to make use of form. On the other hand, Anscombe says that it is matter which makes an individual the individual it is, numerically distinct from other individuals of the same (and other) species. Yet this is an issue about numerical distinctness rather than unity. It is perfectly consistent to say that Socrates is one man because of his form, which unifies his matter into a single whole, and he is a numerically distinct individual from Callias because his matter is numerically distinct from Callias’ matter.