coldmountain: "I'd like to ask for some thoughts regarding the idea of Buddha-nature in some Buddhist schools, and whether there is any meaningful difference Buddha-nature and Hinduism's atman...."
Astus: "The difference in brief. Those who believe there is an actor behind action think there is a self/soul. Those who realise that the mind is empty, without a self, understand that it is buddha-nature."
Malcolm: "Paradoxically, in Tathāgatagarbha literature, that mind that lacks identity and is empty is being called "self". It is standard Buddhist subversion of Hindu norms, once again. The Tantras do it with Samkhya."
Coldmountain: "What, then, is Buddha-nature? Is it an unconditioned substance? Does it exist independently of change and plurality?"
Malcolm: "Nope, not an unconditioned _substance_."
To what does the term refer to, then? I'm not clear how a belief in an unconditioned, immutable anything fits with the teaching of conditioned-arising.
Malcolms response: That depends on who you ask. In Tibetan Buddhism, according to the Sakya school, tathāgatagarbha is the union of the clarity and emptiness of one's mind. According to the Gelugpa school, it is the potential for sentient beings to awaken since they lack inherent existence; according to the Jonang school, it refers to the innate qualities of the mind which expresses itself in terms of omniscience, etc, when adventitious obscurations are removed. In Nyingma, tathāgatagarbha also generally refers to union of the clarity and emptiness of one's mind.
There is only one Indian commentary on this issue -- the Uttaratantra and its commentary by Asanga.
Xabir: "Similarly, that tathaagatagarbha taught in the suutras spoken by the Bhagavan, since the completely pure luminous clear nature is completely pure from the beginning, possessing the thirty two marks, the Bhagavan said it exists inside of the bodies of sentient beings.
When the Bhagavan described that– like an extremely valuable jewel thoroughly wrapped in a soiled cloth, is thoroughly wrapped by cloth of the aggregates, aayatanas and elements, becoming impure by the conceptuality of the thorough conceptuality suppressed by the passion, anger and ignorance – as permanent, stable and eternal, how is the Bhagavan’s teaching this as the tathaagatagarbha is not similar with as the assertion of self of the non-Buddhists?
Bhagavan, the non-Buddhists make assertion a Self as “A permanent creator, without qualities, pervasive and imperishable”.
The Bhagavan replied:
“Mahaamati, my teaching of tathaagatagarbha is not equivalent with the assertion of the Self of the non-Buddhists.
Mahaamati, the Tathaagata, Arhat, Samyak Sambuddhas, having demonstrated the meaning of the words "emptiness, reality limit, nirvana, non-arisen, signless", etc. as tathaagatagarbha for the purpose of the immature complete forsaking the perishable abodes, demonstrate the expertiential range of the non-appearing abode of complete non-conceptuality by demonstrating the door of tathaagatagarbha.
Mahaamati, a self should not be perceived as real by Bodhisattva Mahaasattvas enlightened in the future or presently.
Mahaamati, for example, a potter, makes one mass of atoms of clay into various kinds containers from his hands, craft, a stick, thread and effort.
Mahaamati, similarly, although Tathaagatas avoid the nature of conceptual selflessness in dharmas, they also appropriately demonstrate tathaagatagarbha or demonstrate emptiness by various kinds [of demonstrations] possessing prajñaa and skillful means; like a potter, they demonstrate with various enumerations of words and letters. As such, because of that,
Mahaamati, the demonstration of Tathaagatagarbha is not similar with the Self demonstrated by the non-Buddhists.
Mahaamati, the Tathaagatas as such, in order to guide those grasping to assertions of the Self of the Non-Buddhists, will demonstrate tathaagatagarbha with the demonstration of tathaagatagarbha. How else will the sentient beings who have fallen into a conceptual view of a True Self, possess the thought to abide in the three liberations and quickly attain the complete manifestation of Buddha in unsurpassed perfect, complete enlightenment?"
~ Lankavatara Sutra
(33) Further, in his practice of samadhi, such a good person's mind is firm, unmoving, and proper and can no longer be disturbed by demons. He can thoroughly investigate the origin of all categories of beings and contemplate the source of the subtle, fleeting, and constant fluctuation. But if he begins to speculate about self and others, he could fall into error with theories of partial impermanence and partial permanence based on four distorted views.
First, as this person contemplates the wonderfully bright mind pervading the ten directions, he concludes that this state of profound stillness is the ultimate spiritual self. Then he speculates, "My spiritual self, which is settled, bright, and unmoving, pervades the ten directions. All living beings are within my mind, and there they are born and die by themselves. Therefore, my mind is permanent, while those who undergo birth and death there are truly impermanent."
Because of these speculations of impermanence and permanence, he will fall into externalism and become confused about the Bodhi nature. This is the third externalist teaching, in which one postulates partial permanence.
~ Shurangama Sutra