Śūnyam and Śūnyatā
ŚŪNYAM AND ŚŪNYATĀ
ŚŪNYAM AND ŚŪNYATᾹ . "Empty," "open," "devoid," "nothing," and "nonexistent" are words used to translate the term śūnyam. "Emptiness," "openness," "nothingness," "nonsubstantiality," "relativity," and "the inexhaustible" have been used to translate śūnyatā. These two terms, of major importance in Buddhism, have been used to express a philosophical idea, a focus of meditation, a religious attitude, and a manner of ethical action. "Emptiness" may thus indicate deprivation (or self-substantiated reality in conventional experience), a complex implicit interrelatedness of all existing things, or blissful perfect freedom (from anxiety, anger, and pain). As general religious terms, śūnyam and śūnyatā are used in an attempt to indicate and incite an awareness of "the way things really are" (yathābhūtam ). The complexity of the concept expressed as "emptiness" derives from the recognition in Buddhism that teaching the truth about life is urgent for alleviating suffering, but that implicit in thinking and speaking resides a tendency to create an illusion (of self-sufficient realities) that is itself the cause of that suffering. The teaching of "the emptiness of things" is a medicine for the spiritual illness seen wherever there is greed, hate, and self-delusion; it is a response to a universal, problematic condition that is found in particular specific forms and thus requires different kinds and levels of correction. Assertions about the empty nature of existence pertain to different objects of concern, for example, conventional phenomena, the basic (usually hidden but more fundamental) causal factors of existence, the highest mode of perceiving phenomena, or the nature of everything. Similarly, different Buddhist schools have recognized the value of different interpretations but have judged the value of a particular interpretation on a scale from the most superficial understanding (for beginners) to the most profound (for spiritual adepts). In all the interpretations and explanations, however, there is a clear recognition that the notion of emptiness is closely tied to the practice of perceiving existence in an "empty manner," which, in turn, results in behavior typified by patience, compassion, strength of character, and morality.
Teaching of Emptiness as Part of the Bodhisattva Path
During the second century bce, Buddhist teachers in India emphasized "emptiness" as a basic description of the nature of existing things. They were known as "teachers of emptiness" (śūnyavādins ). Their approach to enlightenment is dramatically portrayed in the Prajñāpāramitā Sūtras (The perfection of wisdom discourses). These sūtra s maintain that the teaching and meditation training of the contemporary traditional masters, as depicted in the analysis of the Abhidharma Piṭaka, resulted in only a partial enlightenment. The Abhidharma masters had insight only into the emptiness of "the self" and general empirical phenomena, which they could perceive by breaking up conventional perceptions of oneself and "the objective world" into their fundamental causal factors (dharma s). While reviewing the dharma s was recognized to be a monastic skill that provided the foundation for the cultivation of nonattachment to the self and the world, the "teachers of emptiness" held that such a review, with its emphasis on attaining nirvāṇa by avoiding attachment to the "constructed world," could itself become a subtle attachment. To prevent attachment to dharma analysis and the expectation of an individual nirvāṇa they insisted that even the dharma s, together with their identifying characteristics, had to be seen as empty. All distinctions, including those between nirvāṇa and the world in flux (saṃsāra ) and between enlightenment and non-enlightenment, were empty of inherent characteristics. The emptiness of all things is a significant part of the Bodhisattva Path to enlightenment in Mahāyāna (Great Vehicle) Buddhism (which developed in northern India and spread to China, Korea, Japan, and Tibet). This path is a spiritual training that begins with instruction of the Buddha's Middle Way to avoid attachment to "the appearances of the world" and acquisition of self-constricting energy (karman ). The path includes putting the teaching into practice (perhaps through many lifetimes and even aeons of time) by meditation, by moral action that results in "seeds of virtue," and eventually by the formation of "the thought of enlightenment" (bodhicitta ) and the earnest resolution (praṇidhāna ) to work for the welfare of all living beings. Progress on the path includes the perfection of charity, morality, effort, and wisdom. A distinguishing character of this wisdom is that the recognition of emptiness is combined with compassion for all living beings. Such wisdom is cultivated through a skill (upāyakauśalya ) to fully engage the conditioned world (saṃsāra ) without being tainted by its evil, delusion, and compulsive drivenness toward pain. The Bodhisattva Path is elaborated in subsequent centuries in such texts as the Madhyamakāvatāra (Entering the Middle Way) by Candrakīrti (sixth century ce), the Śiksāsamuccaya (Compendium of Precepts) by Śāntideva (eighth century ce), and the Bhāvanākrama (The course of spiritual development) by Kamalaśīla (eighth century ce). In claiming to perfect the meditational practice of the Abhidharma masters within the Indian Buddhist community, the composers of the Prajñāpāramitā Sūtras claimed—as did the composers of such other early Mahāyāna discourses as the Saddharma-puṇḍarīka Sūtra (Lotus of the good law discourse) and the Vimalakīrtinirdeśa Sūtra (Exposition by Vimalakīrti)—that their teaching of emptiness was consistent with, and indeed the deepest comprehension of, the earliest recorded doctrine of the Buddha. The earlier recorded discourses (nikāya s) had already used the notion of emptiness to describe the ephemeral quality of phenomena, especially the lack of permanence and self-existence of perceived objects. During meditative quieting of the mind, and through a descriptive analysis of the many factors that constitute perceived objects, the monk sought to remove mental and emotional disturbances that arose from false expectations of permanence. Though everyday phenomena "exist" in a composite, conditioned manner, they are empty of anything that is permanent or self-existent. In articulating this path of nonattachment to mental, emotional, or material "things," the nikāya s use designations such as "empty," "impermanent," and "nonessential"; however, they are aware that in conventional speech an assertion implies the denial of its opposite claim. To avoid such implications they also warn that enlightenment is not the same as holding a view of emptiness, of nonexistence rather than existence, of "it is not" rather than "it is." Rather, one should avoid clinging to ideas or apprehensions that divide one's experience into "is" and "is not," "being" and "nonbeing," or "if not this, then that." The path to enlightenment, expounded by the "teachers of emptiness" in the Praj-ñāpāramitā Sūtras, absorbed the earlier Buddhist recognition that the self and objects of perception are empty of self-existence. The "teachers of emptiness" extended the awareness of the empty nature to everything. Thus the dharma s (causal factors of existence), the Buddha's teaching, the path to liberation, the beings who seek liberation, liberation, and "emptiness as a teaching" were all viewed as being empty—all viewed in an empty manner. The Bodhisattva Path was described as "no-path" or "non-coursing"; the Buddha's position was "having no place to stand." The attainment of enlightenment was "no-attainment." There was no defilement, no purification; no arising and no dissipation of existence; and no release from existence to attain nirvāṇa —because all these are empty of self-substantiated reality, inherent characteristics, and essential value. This kind of teaching was meant neither for the "worldling" attached to the things of existence nor even for a novice in the Buddha's Middle Way. Such people as these might become fearful and despondent or might interpret the teaching as a nihilistic view or simply as a negative expression of a transcendent essentialism. Only courageous pursuers of truth who had accumulated a resource of spontaneous virtue and clarity of perception could see that such "non-coursing" implies complete interrelatedness with all living beings and that the deepest cognition of emptiness is expressed as compassion.
The MĀdhyamika School
The effort to formulate and justify the insight that all things are empty while living in a spontaneous, comprehensively caring manner was systematized differently by two Indian schools of Buddhism, the Mādhyamika ("middle way") and the Yogācāra ("yoga practice") schools. Nāgārjuna (late second century ce) is often regarded as the founder of the Mādhyamika school. The invocation of one of his major writings, the Mūlamadhya-makākarikās (The Fundamentals of the Middle Way), includes a summary of "eight negations" that has epitomized the emptiness teaching for subsequent generations: no origination, no dissipation; no permanence, no ending; no differentiation, no identity; no coming (into existence), no going (from existence). Throughout this work, Nāgārjuna analyzes basic philosophical notions and views, for example, causal conditions, time, karman, self (ātman ), the fully enlightened one (tathāgata ), and nirvāṇa. He shows that none exists in the sense of self-sufficient existence (svabhāva ) and, thus, that each is empty (of self-sufficient existence). At the same time, he demonstrates that all phenomena exist because emptiness is the same as dependent co-origination (pratītya-samutpāda ). As radical relational existence, emptiness is identical to existence. Contrary to the claim of his opponents that to designate everything as "empty" is to say that nothing exists, Nāgārjuna insists that one can account for changing existence or enlightenment only if one recognizes that these lack self-existent reality (i.e., emptiness as dependent co-origination).
To perceive all existing things as dependently co-originating, or empty, requires a shift from the conventional mode of perception. Conventional experience divides the world into likes and dislikes, desires and fears, and "you" and "me" as separate entities. This hides the fact that these perceptions can exist only in interrelationship. To perceive through the deep awareness of emptiness, people must become aware of how they construct attachments and fears while perceiving, conceptualizing, and judging. Concepts and language create the places for sensations and emotions "to reside." Therefore, they are a prime focus for dissipating attachments. Nāgārjuna and his followers in the Mādhyamika school use a critical dialectic to show how concepts that presume to describe independent, self-sufficient reality are illusory. The general structure of this dialectic is to assert that any self-subsistent, independent entity is unchanging and unrelated; to claim that such an entity accounts for any phenomenon in the continually changing world is either logically contradictory or contrary to common experience. Likewise in this dialectic is a rejection of the common assumption that any denial of something logically requires the opposite positive assertion. That is, when denying that an entity has "being," a person implicitly asserts that the entity has "nonbeing." Thus in the Mādhyamika dialectic a common argumentative procedure is the denial of "four alternatives" (catuṣkoti). For example, in discussing the nature of the perfectly enlightened one (tathāgata ), Nāgārjuna states: "One can say neither 'empty' nor 'non-empty'; nor both, nor neither. The purpose of these designations is for communication only" (Mūlamadhyamakakārikās 22.11). The religious significance of the critical dialectic is to show the "non-abiding" character of "the way things are." The empty character of existence cannot be encapsulated in language or in any perception that implicitly assumes permanent essential qualities or substances. By dislodging a person's hope that language or logic can capture the empty, or intrinsically relational dynamic of existence, one can avoid the delusion of permanence as a condition for happiness and serenity. The use of logic to justify the emptiness of experienced "things," juxtaposed with the assertion that language distorts a true cognition of emptiness, led to the doctrine of two levels or modes of truth. The notion of two modes of truth recognizes that logic, metaphor, or verbal description has use in conventional day-to-day experience but that such conventional use also hides and distorts a deeper (or higher) cognition known through an immediate, direct, intuitive awareness. For the Mādhyamika, emptiness was the object of highest knowledge and, at the same time, accounted for the possibility of the conditioned, conventional forms in everyday life. However, to say that emptiness is "the object" of knowledge does not mean at the highest level of truth that emptiness exists as a separate entity. This is the realization of the "emptiness of emptiness." Because "the two modes of truth"—like everything else—are related but distinct, the systematic formulation of how they were to be defined and related became a focus of much subsequent discussion and writing throughout the millennia. Within the Mādhyamika school and between various schools or lineages of teaching in India, Tibet, China, Korea, and Japan, there were various understandings of the two levels of truth and the meaning of emptiness in the context of realizing the highest truth. Within Mādhyamika, the subschool called Prāsaṅgika (from prasaṅga, a logical method of "necessary consequence") stressed the distorting character of all concepts and logic. Its adherents applied their rigorous "consequential dialectic" to all concepts that purported to express the highest truth, in order to dislodge any pretense of language to do so. Language and logic are, nevertheless, important tools to show the self-contradictory and distortional character of conceptual formulation. In his Prasannapadā (Clearly worded commentary), on Nāgārjuna's Mūlamadhyamakakārikās, Candrakīrti advocates this position, emphasizing that the awareness of emptiness is the destruction of all views or formulations. Even the negation of self-existent reality (svabhāva) is not a positive cognition of anything. In his commentary, Candrakīrti argues against Bhāvaviveka, an important spokesperson for the other Mādhyamika subschool, the Svātantrikas ("Independents"). The Svātantrikas held that language and logic cannot express the most profound aspects of the highest truth but that some assertions express the truth of emptiness more accurately than others. Further, the accurate statements are amenable to verification within conventional rules of logical justification. This discussion continued outside India, especially in the development of Tibetan Buddhist lineages. For example, the Prāsaṅgika position was elaborated by the Sa skya and later by the Rnying ma pa commentators, while the Svātantrika position was advocated by the Dge lugs pa lineage, including the great master Tsong kha pa (1357–1419 ce). The Tibetan monasteries developed their own lineages by drawing on ideas and interpretations from various earlier schools. They attempted to synthesize the teachings from different sources and thus develop a more complete view, while the Prāsaṅgika view is said to be the basis for knowing emptiness and is found in all four divisions of the tantra s ("deep meaning texts").
The YogĀcĀra School
The ideas of the other major Indian school of Mahāyāna Buddhism, the Yogācāra, were systematically formulated during the fourth century ce by the two monks Asaṅga and Vasubandhu. Like the Mādhyamikas, the Yogācāras also recognize that all phenomena are empty (i.e., conditioned, without selfsubsisting reality). However, they insist that the "courser in wisdom" should positively affirm the ultimate reality of consciousness. It is consciousness that is empty and that knows in an empty or delusive manner. All living beings, Asaṅga claims in his Madhyānta-vibhaga (Distinguishing between the middle and extremes), have the capacity to pervasively construct "that which is not there" (abhūta-parikalpa ). This capacity artificially divides the interdependent world into many dualities, for example, subject and object, being and nonbeing. The elimination of dualistic fabrication is true emptiness. Consciousness, in Yogācāra reflection, is the comprehensive reality and is composed of three kinds of reality: completely fictive or illusory (parikalpita-svabhāva ), dependent or conditioned (paratantra-svabhāva ), and truly real or nondual (pariniṣpanna-svabhāva ). Through the practice of the Bodhisattva Path the illusory reality is recognized for what it is: nonexistent. This recognition purifies the conditioned existence, which itself is not a real object but a modality of consciousness. When this is realized, the nonduality (or emptiness) of all things is manifest and exists as the ultimate reality (paramārtha sat ). Whereas the Mādhyamikas stress that both the conditioned forms and the unconditioned reality are empty, the Yogācāras emphasize that the true reality is neither empty nor nonempty.
Another aspect of the Yogācāra emphasis on consciousness, found in several Indian discourses that contributed to the Mahāyāna understanding of ultimate reality, was the notion of the "matrix of enlightened reality" (tathāgata-garbha ). Vasubandhu had described the basis of multiple kinds of consciousness as a "store consciousness" (alaya-vijñana ). This store consciousness contains both pure and impure "seeds" (bīja s) that influence subsequent consciousness. Similarly, the tathāgata-garbha is the womb, or matrix, from which pure consciousness in the manifested world arises. Such a Mahāyāna text as the Srīmālādevī-siṃhanāda Sūtra (The lion's roar of Queen Srimala) equates the tathāgata-garbha with emptiness. Here "emptiness" means both "being devoid of impurities" and the natural "power of enlightenment" to produce nonattached consciousness in worldly forms. The ultimate nature of the tathāgata-garbha is perfect purity. It is manifested in forms as well as being the formless reality. However, enlightened reality—also called "the Buddha nature"—is said to be nonempty in respect to the virtues of Buddhahood, which are manifested in the phenomenal world. Insofar as there is a strong emphasis on enlightened reality, which is manifest in particular concrete forms, the tathāgata-garbha is said to be neither simply empty nor simply nonempty. In India during the second half of the first millennium ce, in China beginning in the fifth century ce, and in the development of the Tibetan lineages, Buddhist scholars developed several formulations of the relation between the conditioned and the unconditioned realities, between the pure and the impure conditioning influences, and between emptiness and conditional form.
Emptiness in Chinese and Japanese Schools
In China the Mādhyamika school maintained a teaching lineage for several centuries from the fifth century ce on as the Sanlun ("three [middle way] treatises") school. The teachings of the Mādhyamika were studied in Japan from the seventh century ce on but without a separate community following a lineage succession. The Yogācāra doctrine was transmitted to China through the translation of texts and a lineage of teachers that became known as the Faxiang ("characteristics of dharma") school. This school was transmitted to Japan during the seventh and eighth centuries ce, where it was known as the Hossō school. The Chinese Mahāyāna Buddhists, during the fifth and sixth centuries, wrestled with the cognition of emptiness first in relation to Neo-Daoist notions of nothingness (kong ), which implied that emptiness is a primary source from which all phenomenal forms arise. In the flowering of Buddhism in China (from the sixth century ce through the first half of the ninth century ce), Buddhist scholars understood emptiness within the context of the broadbased Chinese philosophical problem of the relation between the substance or foundation (ti) of everything and its function or appearance (yong) in the changing world. Within the Sanlun school, contrasting understandings of this relation between substance and function are found in the writings of Sengzhao (374–414 ce) and of Jizang (549–623 ce). Sengzhao assumed the identity of substance and function, affirming that emptiness is the foundation of all things that appear through dependent co-arising and is the nature of insight that recognizes the illusory (empty) character of phenomena; thereby the enlightened person abides in non-abiding (emptiness) and moves (in an empty manner) in conditioned existence. Jizang, on the contrary, held that substance and function need to be clearly distinguished, and emphasized that the highest truth is manifest when the conventional truth is negated. Emptiness is basically the dialectical negation of both being and nonbeing and of both affirmation and negation. The highest truth is known in conditioned existence when names and characteristics of things are negated or transcended in nonphenomenal awareness. During the sixth and seventh centuries ce, the Chinese Buddhists synthesized the notions of emptiness, multiple kinds of truth (reality), and dependent co-arising within a cosmological context in developing two distinctly Chinese schools or teaching lineages. These were Tiantai, formulated by Zhiyi (531–597 ce), and Huayan, systematized by Fazang (643–712 ce). Both are attempts to relate substance and function in one harmonious and interrelated matrix of reality. Chih-i held that there was a threefold truth—the empty (kong), the provisional (jia ), and the middle (zhong) —and that these three parts are reciprocally identical and simultaneous. Rather than view the truths in a lower-to-higher order, he presented them as different modalities of one universal consciousness. While they appear to be separate processes, he maintained, in their deepest character of interrelatedness they are one undifferentiated matrix whose principle is beyond dualistic or linear comprehension. Fazang held that the "nature of things" was emptiness, by which he meant the harmonious interdependent co-arising of particular, concrete phenomena. Such a universe is "the body of the tathāgata. " Rather than devaluing particular phenomena because they are conditioned (non-eternal), his system insists that each has supreme value in its interrelatedness to everything else. Fazang held that the three natures (levels of awareness) proposed by Yogācāra teachers are intrinsically interrelated, and together form a whole, because they are all empty. The most profound nature is the incomprehensible "suchness" (formless emptiness), which is also the emptiness of the interrelatedness of conditioned existence (dependent co-origination); this, in turn, is also the non-self-substantial (empty) nature of illusory mental construction. To know the intrinsic emptiness ("suchness") of all forms is the highest awareness. However, most people do not see the complex emptiness of everything. At a lower level of awareness, one can also say that the evil and pain experienced in the world represent only the potential for realizing incomprehensible "suchness" and that the tathāgata-garbha causes the transformation of enlightenment in particular minds and moments of consciousness. Nevertheless, in reality, the world is an inconceivably vast expression of emptiness that is the glorious manifestation of unchanging fullness, an overbrimming potential of "openness." Another very important expression of emptiness is found in the "Meditation school," which is known as Chan in China and Zen in Japan. The focus in Chan communities has been, and is, on "the practice of emptiness." The basic negation of concepts as inadequate communication of "the way things are" and an emphasis on quieting the mind and extending the empty mode of perception into daily life continue the themes found in the Bodhisattva Path as portrayed in the Prajñāpāramitā Sūtras. Zen masters have commented on these discourses as well as on the central Mādhyamika and Yogācāra treatises and on the poems and comments of previous Zen masters. Zen is the practice of manifesting "the Buddha mind," which is also "no-mind." The realization of "no-mind" is the loss of attachment to conventional perceptions, theoretical concepts about reality, and self-images. In that state of awareness, a Zen practitioner is directly confronted with emptiness—not as an idea or as the denial of an idea but as "what is at that moment." Many Zen masters have emphasized that the notion of emptiness is misleading or useless when it is used to describe a distinctive quality of experience. At the same time, "emptiness" is prominently used as a focus of meditation, in which the meditator is called on to "become emptiness." Basically, it is a mental tool to dissipate attachment to images and concepts. In the contemporary discussion of cross-cultural philosophy and interfaith dialogue in which Buddhists are involved, the notion of emptiness and the negating dialectic are important points of engagement with other philosophies. The empty perception of "the way things are" has been compared with the critique of reason given by the eighteenth-century German philosopher Immanuel Kant and with the distorting character of language described by the twentieth-century philosophers Ludwig Wittgenstein and Martin Heidegger. The claim that all things are dependently co-originated is compared with similar concepts in "process philosophy," as expounded, for example, in Alfred North Whitehead's Process and Reality. The notion of emptiness forms a central concern in the philosophical thought of the contemporary Japanese philosophers Nishida Kitarō and Nishitani Keiji as they discuss the nature of goodness, existence, and selfhood in a cross-cultural philosophical context. In interfaith dialogue, emptiness is a major topic in the Christian and Buddhist discussion of the nature of ultimate reality, human nature, and religious awareness. Likewise, the empty apprehension of oneself that is best manifested in compassion is compared with mystical disciplines that require the love of others found in various religious traditions. As a fundamental and multidimensional concept, emptiness continues to engage reflective people who pursue the tantalizing question of the nature of things.
Ālaya-vijñāna; Bodhisattva Path; Buddhism, Schools of, article on Tibetan and Mongolian Buddhism; Buddhist Philosophy; Chan; Dharma, article on Buddhist Dharma and Dharmas; Huayan; Mādhyamika; Nāgārjuna; Nirvāṇa; Numbers, article on Binary Symbolism; Prajñā; Pratītya-samutpāda; Soteriology; Tathāgata-garbha; Tiantai; Yogācāra; Zen.
A good historical introduction to the development of the "teaching of emptiness" in India is Edward Conze's Buddhist Thought in India (London, 1962); his translations of the Prajñapāramitā Sūtras, especially The Perfection of Wisdom in Eight Thousand Lines and Its Verse Summary (Bolinas, Calif., 1973), are basic for understanding how the term "empty" functions in communicating the Bodhisattva Path. A standard philosophical analysis of Indian Mādhyamika thought, emphasizing the logical dialectic, is T. R. V. Murti's The Central Philosophy of Buddhism, 2d ed. (London, 1970), and a useful linguistic and philosophical analysis of the translation of the Indian Madhyamika into Chinese thought is found in Richard H. Robinson's Early Mādhyamika in India and China (Madison, Wis., 1967). In my book Emptiness: A Study in Religious Meaning (New York, 1967) I compare the religious language structure of the term "emptiness" and the Indian Mādhyamika dialectic with other kinds of religious expression in order to delineate their religious meaning. A collection of essays edited by Minoru Kiyota, Mahāyāna Buddhist Meditation (Honolulu, 1978), contains several excellent essays on the meaning of emptiness in Buddhist theory and practice in India, Tibet, China, and Japan. An introduction to the understanding of emptiness within the meditative practice of Tibetan Buddhism is Practice and Theory of Tibetan Buddhism, edited and translated by Geshe Lhundup Sopa and Jeffrey Hopkins (New York, 1976). A lengthy explanation of the realization of emptiness according to the texts and oral traditions of the Prāsaṅgika-Mādhyamika tradition in Tibet is Jeffrey Hopkins's Meditation on Emptiness (London, 1983). Two different and complementary interpretations of emptiness in Huayan Buddhism are found in Garma C. C. Zhang's The Buddhist Teaching of Totality (University Park, Pa., 1971) and Francis H. Cook's Huayan Buddhism (University Park, Pa., 1977). A classic introduction to the Zen negation of mental images is D. T. Suzuki's The Zen Doctrine of No-Mind (London, 1949), which is also found in an abbreviated form in Zen Buddhism: Selected Writings of D. T. Suzuki, edited by William Barrett (Garden City, N.Y., 1956). Nishitani Keiji's Religion and Nothingness, translated by Jan van Bragf (Berkeley, Calif., 1982), is a prime example of a contemporary philosophical use of the notion of emptiness to explore the deepest awareness of existence.
Burton, D. Emptiness Appraised: A Critical Study of Nagarjuna's Philosophy. Richmond, U.K., 1999.
Hopkins, J. Emptiness in the Mind-Only School of Buddhism: Dynamic Responses to Dzong-ka-ba's The Essence of Eloquence: I. Berkeley, 1999.
Hopkins, J., and E. Napper. Meditation on Emptiness. Boston, 1996.
Ichimura, S. Buddhist Critical Spirituality: Prajña and Sunyata. Delhi, 2001.
King, R. Indian Philosophy: An Introduction to Hindu and Buddhist Thought. Washington, D.C., 1999.
Napper, E. Dependent-Arising and Emptiness: A Tibetan Buddhist Interpretation of Madhyamika Philosophy Emphasizing the Compatibility of Emptiness and Conventional Phenomena. Boston, 2003.
Viévard, L. Vacuité (Sunyata) et Compassion (Karuna) dans le Bouddhisme Madhyamaka. Paris, 2002.
Williams, P., and A. Tribe. Buddhist Thought: A Complete Introduction to the Indian Tradition. New York, 2000.
Frederick J. Streng (1987)