nirvāna The classic Mahāyāna Yogacara view posits that there are at least two types of nirvana, holding that what is called ''apratiṣṭhita-nirvana'' ("non-abiding", non-localized", "non-fixed") to be the highest nirvana, and more profound than ''pratiṣṭhita-nirvāṇa'', the ‘localized’, lesser nirvana. According to the classic Indian theory, this lesser, abiding nirvana is achieved by followers of the "inferior" vehicle (hinayana) schools which are said to only work towards their own personal liberation. From this perspective, the hinayana path only leads to one's own liberation, either as sravaka (listener, hearer, or disciple) or as pratyekabuddha (solitary realizer). According to Robert Buswell and Donald Lopez, ''apratiṣṭhita-nirvana'' is the standard Mahāyāna view of the attainment of a Buddha, which enables them to freely return to samsara in order to help sentient beings, while still being in a kind of nirvana. The Mahāyāna path is thus said to aim at a further realization, namely an active Buddhahood that does not dwell in a static nirvana, but out of compassion (karuṇā) engages in enlightened activity to liberate beings for as long as samsara remains. Apratiṣṭhita-nirvana is said to be reached when bodhisattvas eradicate both the afflictive obstructions (klesavarana) and the obstructions to omniscience (jñeyavarana), and is therefore different than the nirvana of arhats, who have eradicated only the former. According to Alan Sponberg, apratiṣṭhita-nirvana is "a nirvana that is not permanently established in, or bound to, any one realm or sphere of activity". This is contrasted with a kind of nirvana which is "permanently established or fixed (pratiṣṭhita) in the transcendent state of nirvana-without-remainder (nirupadhisesa-nirvana)." According to Sponberg this doctrine developed among Yogacara Buddhists who rejected earlier views which were based on an individual liberation aimed at a transcendent state, separated from the mundane sphere of human existence. Mahayana Buddhists rejected this view as inconsistent with the universalist Mahayana ideal of the salvation of all beings and with the absolutist non-dual Mahayana perspective that did not see an ultimate distinction between samsara and nirvana. Sponberg also notes that the Madhyamika school also had a hand in developing this idea, due to their rejection of dualistic concepts which separated samsara and nirvana and their promotion of a form of liberation which was totally without duality. Though the idea that Buddhas remain active in the world can be traced back to the Mahasamghika school, the term apratiṣṭhita-nirvana seems to be a Yogacara innovation. According to Gadjin Nagao, the term