 Divisibility into subjective parts, of course, is on the face of it very different from the question of division from all other things, so nicely exemplified in Black’s example of the qualitatively identical spheres. Scotus’s assumption, however, is that both questions can be answered in the same way. Thus Scotus supposes that the explanation for distinction is the explanation for indivisibility, and the rough outline of what he is thinking looks as follows. The explanation for distinction is primary, in the sense that what distinction needs is explanation by items (haecceities) that are irreducibly numerically distinct from each other – as Scotus puts it, “primarily diverse” (primo diversa) – and have nothing real whatever in common: “they agree in nothing the same” (Scotus, Ordinatio II, d. 3, p. 1, qq. 5–6, n. 186 (Scotus [OO], 7:483; Spade (1994), 106)). (This does not entail that the things thus distinguished, as opposed to the haecceities that distinguish these things, have nothing whatever in common. Scotus’s point is that the haecceity is needed as a constituent of a being that shares its nature with something else in the manner described in the previous section.) According to Scotus, merely numerical distinction – as opposed to (say) specific distinction – entails that each of the things distinguished has numerical singularity. And numerical singularity entails indivisibility (into subjective parts), for what allows a common nature to be divided (into subjective parts) is its possession of less-than-numerical unity.