In this way...

In this way, expressions such as ‘simplicity,’ ‘composition,’ ‘indeterminate,’ ‘determinate,’ ‘common’ and ‘distinct,’ ‘general’ and ‘specified,’ ‘absolute’ and ‘limited,’ have appeared in the cases above, and the expression ‘individuation’ ( tashakhkhuṣ ) mentioned in previous chapters, should be added to them. But among these there are two pivotal concepts, the concepts of unity and multiplicity. We now turn to the explanation of these two concepts.

Types of Unity and Multiplicity Each specific whatness differs from the others. If two whatnesses are simple, then they will not even have a single common aspect, and likewise two compound whatnesses of two categories also will not have a common aspect. In view of the fact that a whatness may be considered by itself or along with other whatnesses, two opposite concepts may be abstracted: ‘one’ and ‘many.’ The unity which is related to each complete whatness is called specific unity.

The reiteration of its form in one or more minds does not damage its unity, for what is meant is conceptual unity, not the unity of its mental existence. Likewise, when we consider a common essential aspect of several compound whatnesses, another sort of unity is attributed to it, called generic unity. In contrast to these two types of unity, there is also numerical unity, which is predicated to each individual belonging to a whatness.

Its criterion is the same individuation the ancient philosophers considered to be due to individuating accidents. The correct [position] is that this individuation and this unity are essential attributes of individual existence, accidentally attributed to whatness.

The individuals of a whatness which have an essential numerical multiplicity are called, ‘one by species,’ likewise the species which are of a single genus and are essentially multiple in species are called ‘one by genus.’ It is clear that these two types of unity are not true attributes of individuals and species, but are attributed to them accidentally.

It is to be concluded from this that essential whatish unity is an attribute of species and genus, and is predicated accidentally to individuals and species. To the contrary, individual unity is really an attribute of individual existence and is attributed accidentally to whatness. On the other hand, individuals in the external world have numerically distinct existences to which multiplicity is essentially attributed.