Yogacarin Philosopher Vasubandhu

According to Buddhism, consciousness arises as a by-product of the contact of a sense organ with its corresponding sphere of sense objects. The eye contacting visibles (e.g., colors and shapes) produces visual consciousness; likewise for the remaining four senses (hearing, smell, taste, and touch). The mental organ operates similarly. Coming into contact with the sphere of mental objects, mental consciousness arises. Hence, there are six sense organs and six corresponding sense realms, which, combined with the six types of resultant consciousnesses, makes eighteen factors altogether. Yogacara accepted these eighteen factors but found them inadequate to explain several issues that had become important for Buddhists, including the sense of selfhood, appropriative propensities, continuity of experience, and how projection worked. To address these issues, Yogacara expanded the mental level, resulting in eight rather than six types of consciousness. Mano-vijnana became the sixth sense organ, a kind of empirical consciousness that discerns mental objects as well as the activities of the five senses; manas became the seventh consciousness, responsible for appropriating experience as "mine" and thus infesting experience with a sense of selfhood. The eighth consciousness, alaya-vijnana, was a novel innovation (Kalupahana, 173).

Yogacara used a seed metaphor to describe the process of karmic conditioning. Experience engenders a seed that is planted out of sight (unconsciously retained in the alaya-vijnana), where it remains latent until catalytic conditions bring it to fruition (karmic result, vipaka), and engendering new seeds of the same type. This was a powerful metaphor in agrarian societies. As a warehouse (alaya) to these seeds, the alaya-vijnana was called the all seeds consciousness (sarva-bijaka-vijnana). Since it was the conduit and repository of their fruitions, it was also called vipaka-vijnana (karmic requital consciousness). Since the alaya-vijnana always operates, even when the other seven consciousnesses temporarily cease (e.g., in deep sleep), it was also called foundational consciousness (mula-vijnana). Although it stores karmic seeds and engenders their projection, the alaya-vijnana is a karmically neutral mechanical process (aniv?ta, avyak?ta). Manas appropriate the activities of the other consciousnesses, thinking they are “my” experience, and appropriate the alaya-vijnana as a "self." (Williams, 77)

In the Twenty verses, Vasubandhu refutes the realism of naive and philosophical realists. The realists assert that the objects we perceive exist outside of consciousness, which is the reason that these objects remain stable through (1) time and (2) space; (3) different people can have differing perceptions of a thing and yet reach a consensus about it; and (4) the objective world operates by determinate causal principles, rather by than imaginary, ineffective fantasies. The verse one is that "mental representations seem to be correlated with external (non-mental) objects; but this may be no different from situations in which people with vision disorders 'see' hairs, moons, and other things that are not there.'" While the verse two says that "If there is perception and consciousness without any corresponding external object, any idea could arise at any time or in any place, different minds could contain ideas of different objects at the same time and place, ...