Whiteness and blackness

The Categories primary

Aristotle argues that qualities have contraries and admit degrees of variation, using examples like justice/injustice and whiteness, while noting some qualities, including figure-based ones, cannot vary in degree.

that which is just, that which is white to that which is black. This, however, is not always the case. Red, yellow, and such colours, though qualities, have no contraries. If one of two contraries is a quality, the other will also be a quality. This will be evident from particular instances, if we apply the names used to denote the other categories; for instance, granted that justice is the contrary of injustice and…