One Mind

One Mind (Chin., yi hsin; Jap., isshin).
1. A general term in east Asian Buddhism for a focused, undisturbed mind, or for the process of concentrating the mind on a single object.

2. In the Consciousness-only (Chin., wei-shih) school, a term designating the most fundamental level of mind or consciousness, the evolutions of which in accordance with karma give rise to all the myriad individual phenomena.

3. In Chinese T'ien-t'ai thought, the single mind that serves as the underlying ground of all being, in both its pure and its defiled aspects. Although this idea can be found in previous sources such as the Hua-yen ching and The Awakening of Faith (Mahāyāna-śraddhotpāda Śāstra), the T'ien-t'ai school developed its range of applications further. According to this school, since the very defilements that kept beings imprisoned in saṃsāra were manifestations of the ultimate reality, they could become proper objects of meditation and instruments of liberation. In one T'ien-t'ai formulation, this was like being able to enter and exit one's prison at will, whereas the traditional concept of liberation through the eradication of defilements was like simply destroying the prison. In addition, the idea that ultimate reality could be characterized as Mind represented an advance over traditional Madhyamaka thought and its categories of the ‘Two Truths’. In this scheme, ultimate truth was static, a simple realization about the nature of reality. By characterizing the final nature of things with the term ‘Mind’, the T'ien-t'ai school re-envisioned truth as living and active, and could visualize it as working within the world through the ordinary things in the world to effect the liberation of sentient beings.