Vasubandhu (fl. 4th c.) was, according to Mahayana Buddhist tradition, an Indian Buddhist scholar-monk, and along with his half-brother Asanga, one of the main founders of the Indian Yogācāra school. However, some scholars consider Vasubandhu to be two distinct people. Vasubandhu is one of the most influential figures in the entire history of Buddhism. In the Jodo Shinshu branch of Buddhism, he is considered the Second Patriarch. In Zen, he is 21st Patriarch.
Born a brahmin Vasubandhu was said to have been the half brother of Asanga, another key personage in the founding of the Yogacara School. He resided at Kausambhi in Gandhāra (near modern Allahabad) where he was trained in the orthodox Sarvastivada Order of Buddhism, which had its seat at Kausambhi. He was contemporaneous with King Chandragupta I, the father of Samudragupta. This information temporally places this Vasubandhu in the fourth century CE.
Vasubandu is said to have trained in the Vaibhashika-Sarvāstivādin when he initially studied Vaibhashika-Sarvāstivādin Abhidharma, as presented in the Mahā-vibhāsa. Dissatisfied with those teachings, he wrote a summary of the Vaibhashika perspective in the Abhidharmakośa in verse and an auto-commentary, the Abhidharmakośa-bhāsya, which summarized and critiqued the Mahāvibhāsa from the Sautrāntrika viewpoint.
He is later said to have converted to the Mahāyāna tradition under the influence of his brother, whereupon he composed a number of voluminous treatises, especially on Yogācāra doctrines. Most influential in the East Asian Buddhist tradition was probably the Triṃśikā-vijñaptimātratā, the Thirty Verses on Representation-only and its companion Vimśatikā, but he also wrote a large number of other works, including:
- a commentary to the Mahāyāna-samgraha
- the Daśabhūmikabhāsya (Ten Stages Sutra)
- Mahāyāna śatadharmā-prakāśamukha śāstra
- Amitayus sutropadeśa
- Discourse on the Pure Land
- Vijnaptimatrata Sastra
- Karmasiddhiprakarana (A Treatise on Action)
Contribution to Buddhist logic and the Dharmic logico-epistemological tradition
Vasubandhu contributed to Buddhist logic and is held to have been the origin of 'formal logic' in the Dharmic logico-epistemological tradition. Vasubandhu was particularly interested in 'logic' to fortify his contributions to the traditions of dialectical contestability and debate.
Vāda-vidhi (English: "Method for Argumentation")
Anacker (2005: p.31) holds that:
A Method for Argumentation (Vāda-vidhi) is the only work on logic by Vasabandhu which has to any extent survived. It is the earliest of the treatises known to have been written by him on the subject. This is all the more interesting because Vāda-vidhi marks the dawn of Indian formal logic. The title, "Method for Argumentation", indicates that Vasabandhu's concern with logic was primarily motivated by the wish to mould formally flawless arguments, and is thus a result of his interest in philosophical debate.
Vasubandhu: a possible conflation of two or three distinct personages
Erich Frauwallner, a mid-twentieth century Buddhologist, sought to distinguish two Vasubandhus, one the Yogācārin and the other a Sautrāntika, but this view has largely fallen from favor in part on the basis of the anonymous Abhidharma-dīpa, a critique of the Abhidharmakośa which clearly identifies Vasubandhu as the sole author of both groups of writings. According to Dan Lusthaus, "Since the progression and development of his thought ... is so strikingly evident in these works, and the similarity of vocabulary and style of argument so apparent across the texts, the theory of Two Vasubandhus has little merit." There is no scholarly consensus on this question at present.
- P. 34 Journal of the Royal Asiatic Society of Great Britain and Ireland, Volume 2001 By Royal Asiatic Society of Great Britain and Ireland
- Dharma Fellowship (2005). Yogacara Theory - Part One: Background History. Source:  (Accessed: November 15, 2007)
- Anacker, Stefan (2005, rev.ed.). Seven Works of Vasubandhu: The Buddhist Psychological Doctor. Delhi, India: Motilal Banarsidass. (First published: 1984; Reprinted: 1986, 1994, 1998; Corrected: 2002; Revised: 2005), p.31
- Dan Lusthaus, "What is and isn't Yogacara." .
- Macmillan encyclopedia of buddhism, volume 1, page 7
- Abhidharma Kosha Bhashyam 4 vols, Vasubandhu, translated into English by Leo Pruden (based on Louis de la Vallée Poussin's French translation), Asian Humanities Press, Berkeley, 1988-90.
- Stefan Anacker, Seven Works of Vasubandhu Motilal Banarsidass, Delhi, 1984, 1998
- David J. Kalupahana, The Principles of Buddhist Psychology, State University of New York Press, Albany, 1987, pp173-192
- Francis H. Cook, Three Texts on Consciousness Only, Numata Center for Buddhist Translation and Research, Berkeley, 1999, pp371-383 ("Thirty Verses on Consciousness Only") and pp385-408 ("Twenty Verses on Consciousness Only")
- Thich Nhat Hanh Transformation at the Base (subtitle) Fifty Verses on the Nature of Consciousness, Parallax Press, Berkeley, 2001; inspired in part by Vasubandhu and his Twenty Verses and Thirty Verses texts