Among those [consciousnesses], mentation is twofold. Since it is the support that acts as the immediate condition, the “mentation which is [any] consciousness that has just ceased” is the support for [the arising of] consciousness. The second is the afflicted mind, which is always congruently associated with the four afflictions of the views about a real personality, self-conceit, attachment to the self, and ignorance. This is the support for the afflictedness of consciousness. [Thus,] consciousness is produced by virtue of the first [aspect of mentation] as its support, while the second one makes it afflicted. [mentation] is a consciousness, because it cognises objects. Since it is [both] immediately preceding and self-centered, mentation has two aspects.

-- Asanga