Mindstream - Mental "stream" Metaphors - Buddhism

Buddhism

There are two entwined mindstreams according to the two truths, the absolute and relative, that are ultimately non-dual according to Atiyoga. One is the divine mindstream of "consciousness" which is engaged in the phowa practice, for example; the other the mindstream of thought and ideation (Tibetan: sem; Sanskrit: manas) (vṛtti-citta).

Gyatso, Jinpa and Wallace (2003: p. 97) identify two kinds of consciousness continua and associate the most subtle state of consciousness continuum, elsewhere identified in this article as the "mindstream substrate", with what is known in Tibetan Buddhist, Dzogchen and Bonpo discourse as "clear light" (Tib: 'od-gsal):

In Vajrayāna Buddhism the subtlest state of consciousness is known as clear light. In terms of categories of consciousness, there is one type of consciousness that consists of a permanent stream or an unending continuity and there are other forms of consciousness whose continuum comes to an end. Both these levels of consciousness - one consisting of an endless continuum and the other of a finite continuum - have a momentary nature. That is to say, they arise from moment to moment, and they are constantly in a state of flux. So the permanence of the first kind is only in terms of its continuum. The subtlest consciousness consists of such an eternal continuum, while the streams of the grosser states of consciousness do end.

Sogyal Rinpoche (1994: p. 73) frames the importance of the stream metaphor in relation to meditation and the nature of mind, the objective of a meditative sādhana:

In the ancient meditation instructions, it is said that at the beginning thoughts will arrive one on top of another, uninterrupted, like a steep mountain waterfall. Gradually, as you perfect meditation, thoughts become like the water in a deep, narrow gorge, then a great river slowly winding its way down to the sea, and finally the mind becomes like a still and placid ocean, ruffled by only the occasional ripple or wave.

Bucknell et al. (1986: pp. 112–113) find numerous references to a stream of thought and imagery:

In Buddhist literature the mental condition in which sequences of imagery and verbalizing run on endlessly is often compared to a flowing stream. We find in the oldest section of the Tipiṭaka the term "stream of consciousness" (viññāṇa-sotaṃ). The same metaphor is often found in the Tibetan literature. The guru Padma Karpo spoke of "thoughts...following one after the other as if in a continuous stream"; Mipham Nampar Gyalba observed, the "stream of images flows unbroken"; and in the Vow of Mahāmudrā, there is reference to 'the mind river'. This manner of speaking is also common at the present day. Tarthang Tülku refers to "the stream of mental images" and 'the flow of thoughts and images'; and David-Neel, in a discussion of the meditation practices she observed in Tibet, speaks of "the continual, swift, flowing stream of thoughts and mental images..."