The doctrine of emptiness, however, received its fullest elaboration at the hands of Nāgārjuna, who wielded it skilfully to destroy the substantialist conceptions of the Abhidharma schools of the Hīnayāna. Since there cannot be anything that is not the Buddha-nature (buddhatā), all that appears is in truth devoid of characteristics. The doctrine of emptiness is the central tenet of the Mādhyamaka school, and a statement of Nāgārjuna's views in support of it may be found in his Mūla-Mādhyamaka-Nārikā.
Emptiness thus becomes a fundamental characteristic of Mahāyāna Buddhism. The teaching is subtle and its precise formulation a matter of sophisticated debate, since the slightest misunderstanding is said to obstruct progress towards final liberation. Emptiness is never a generalized vacuity, like an empty room, but always relates to a specific entity whose emptiness is being asserted. In this way up to twenty kinds of emptiness are recognized, including the emptiness of emptiness. The necessary indiscoverability of essences is the Mādhyamakan emptiness. It is important to distinguish this from nihilism. In Yogācāra (Vijñānavāda), emptiness is taught as the inability to think of an object apart from the consciousness which thinks of that object, i.e. the necessary indissolubility of subject and object in the process of knowing is the Yogācārin emptiness. It is important to distinguish this from idealism and solipsism.
sunyata (shōōn´yətə) [Skt.,=emptiness], one of the main tenets of Mahayana Buddhism, first presented by the Perfection of Wisdom (Prajna-paramita) scriptures (1st cent. BC on) and later systematized by the Madhyamika school. Early Buddhist schools of Abhidharma, or scholastic metaphysics, analyzed reality into ultimate entities, or dharmas, arising and ceasing in irreducible moments in time. The Mahayanists reacted against this realistic pluralism by stating that all dharmas are
without self-nature (svabhava) or essence. This was a radical restatement of the central Buddhist teaching of non-self (anatman). It was declared that not only ordinary objects, but the Buddha, nirvana, and also emptiness itself are all
The teaching attempts to eradicate mental attachment and the perception of duality, which, since it is a basis for aversion to bondage in birth-and-death (samsara) and desire for nirvana, may obstruct the bodhisattva's compassionate vow to save all beings before entering nirvana himself. Wisdom (prajna), or direct insight into emptiness, is the sixth perfection (paramita) of a bodhisattva. It is stressed by both Buddhist writers and Western scholars that emptiness is not an entity nor a metaphysical or cosmological absolute, nor is it nothingness or annihilation.
things are neither existent nor nonexistent, and their true nature is thus called not only emptiness but also suchness (tathata).
See E. Conze, Buddhist Wisdom Books (1958). F. J. Streng, Emptiness (1967).