Consciousness is used exclusively in the sense of distinction-making activities of the mind, which include both the making of the distinctions and the distinctions made. Conscious awareness and what is normally unconscious are both considered aspects of consciousness in the Buddhist sense of the word.

The Consciousness-Only school describes the mind as a system of seven active consciousnesses (vijñāna) which all develop out of the eighth, or storehouse consciousness. The latter is passive and contains the potentials, or “seeds” (bīja), for the development and activity of the first seven consciousnesses. The seventh consciousness acts as a communication link between the eighth consciousness and the first six consciousnesses. It contains the sense of self, of ego individuality, with which it defiles the communications to the first six consciousnesses. The sixth consciousness is a perceptual and cognitive processing center, while the first five consciousnesses are the perceptual awarenesses of eyes, ears, nose, tongue, and body.

Formal division is made among these seven consciousnesses after their emanation from the eighth, but division is totally based upon mental distinction. The eight are still basically "one." To use a simple analogy, let us think of a room with seven light bulbs. You flick on the light switch and seven distinct lights shine. Turn the switch off and the lights disappear. Yet there is just one electric current; the electrical source is comparable to the storehouse consciousness, or, as it is understood after the transformation of consciousness, to the enlightened mind.

The system for describing the eight consciousnesses, and the mental dharmas (caittas) which arise out of them and are dependent upon them, was developed as an important part of a pragmatic psychology of mind. The system can be used to describe, in a manner that is accurate and practical, both mental functioning and the specific techniques employed on the Path to the enlightenment that is Buddhahood. It provides a way to account for mental processes without recourse to the notions of a real, permanent self (ātman)or of real, permanent external (and also internal) objects (dharmas). All actual and potential realms of experience are shown to be contained within the transformations of consciousness and appear as manifestations of the distinction-making mind.

Nevertheless, because of our attachment to and belief in the reality of self and the reality of the “objects” (dharmas) which we perceive and understand to be the external world, the true nature of ourselves and the world is obscured so that we are unaware of it.

“The eye consciousness. We say that eyes see, but it’s not actually the eyes themselves that see. It is the eye consciousness which sees. The ear consciousness. We say the ears can hear, but if you sliced off your ears and laid them aside, would they be able to hear of themselves? If you gouged out your eyes and set them aside, would they be able to see? Could you say, 'I'm not going to the movies, but I'll send my eyes along, and they can take in the show?' Obviously not. The eyes cannot see by themselves. It is the eye consciousness which does the seeing. And where does the eye consciousness com from? From the mind---the Mind King. The same is true for all the other consciousnesses as well...it takes for a self that which basically is devoid of a self. Because of a fixation to a false reckoning, thought movements rage on without stop. The wave patterns within the seventh consciousness are more apparent and forceful, whereas the movements of the eighth consciousness are still and imperceptible. Within the eighth consciousness are stored the seeds of all habit energies and impressions from beginningless time, and there are very subtle movements and a constant state of flux in that sphere.” (EDR IV 27-28)

八識