The mental factors are the modes of operation of the mind-king.

The five universally present mental factors not only operate when thoughts arise, but also function together with the eight consciousnesses in every moment and instant, never departing from them for even a moment. Whenever the eight consciousnesses appear, the five universally present mental factors accompany them in operation. As stated in the first volume of the *Yogācārabhūmi-śāstra*, the five universally present mental factors are the assistants of the mind king. Whenever the mind king operates, it relies on the five universally present mental factors as its assistants; without them, the mind king cannot function.

The operation of the mental factor of attention (manaskāra) is such that, for example, before a seed of consciousness is about to arise, there must be a direction for its arising, and it must determine the location of its emergence—such as arising in the form of a flower before the eyes. When the mind faculty (manas) intends to discern that form, having determined the locus of that object, the seed of consciousness emerges toward the form of that flower in the supreme root (the organ of perception). Alternatively, it may emerge toward the location of a sound, arising where the sound-object appears in the supreme root, or at other locations of the six objects that the mind faculty wishes to discern. Thus, before the seed of consciousness arises, there is an attention (manaskāra), which involves a direction and a position for arising. This mental factor begins to operate before the seed of consciousness emerges and continues to operate unceasingly after its emergence. The modes of operation of the mental factors and the mind king are perfectly integrated; the mental factors constitute the operational modes of the mind king. On the surface, what appears are the operational modes of the mental factors, yet within them are concealed the operational modes of the flowing seeds of the mind king. Although the two are consistent, each has its own distinct mode of operation.

The last of the five universally present mental factors is the mental factor of volition (cetanā). The final function of volition is to create or act. Once volition has completed its creation, it is as if the mind king has completed its creation, and the consciousness either ceases or shifts its locus, at which point the mental factors at that locus also disappear. According to this principle, the operational modes of the mind king and the mental factors are identical; their operations are intertwined. The modes are manifested in the operation of the mental factors, while concealing the modes of the flowing seeds of consciousness, and they are inseparable.

When the seeds of consciousness flow out, they form the essence of the mind king, which is pure because the seeds of consciousness are pure. The seeds of consciousness are neither defiled nor good or evil. However, when combined with the mental factors and operating in the form of mental factors, good, evil, and neutral mental activities arise. Thus, the mental activities of the eight consciousnesses (the mind king) and the mental factors are essentially one; the mental factors are the mental activities of the mind king. When the eight consciousnesses operate, they do so in the form of mental factors, especially in the form of the five universally present mental factors.