Karmasiddhiprakaraṇa (Treatise on Action)

The central argument is that karma—action—is fundamentally a mental event, specifically a 'volition' (cetanā) and the 'information' (vijñapti) it produces, rather than a physical substance that persists independently. Vasubandhu rejects the Vaibhāṣika theory of an 'unfailing' (avipraṇāśa) entity that carries karmic efficacy forward after the action has ceased, arguing that this posits a real entity where only a causal stream is needed . Instead, he argues that karmic traces persist as seeds within the storehouse consciousness (ālayavijñāna), a distinctively Yogācāra solution. Bodily and vocal actions are 'informations' produced by consciousness, not material atoms; they are the outward expressions of a fundamentally mental process. The text thus defends a Yogācāra account of karma against both realist Abhidharma and Sautrāntika objections.

The Sanskrit original is lost, but the text survives in two Chinese translations: Xuanzang's Dasheng chengye lun (Taishō 1609), made in 648 or 651 CE, and an earlier translation by Vimokṣaprajñāṛṣi titled Yechengjiu lun (Taishō 1608) [citation:4][citation:14]. The standard scholarly edition is Étienne Lamotte's 1936 French translation with the Chinese text, published in the Mélanges Chinoise et Bouddhique . Leo M. Pruden's English translation, based on Lamotte's French, was published by Asian Humanities Press in 1988 [citation:1]. A more recent English translation by John P. Keenan, titled A Mahayana Demonstration on the Theme of Action, appears in Three Short Treatises by Vasubandhu, Sengzhao, and Zongmi (BDK America, 2017) . The BDK translation is based on Xuanzang's Chinese and is the most accessible contemporary English version.

The Karmasiddhiprakaraṇa is a systematic revision of the Abhidharma theory of karma that Vasubandhu had presented in the Abhidharmakośa. In the Kośa, Vasubandhu had criticized the Vaibhāṣika doctrine of the 'unfailing' entity but had not yet developed a full alternative. The Karmasiddhiprakaraṇa supplies that alternative: the storehouse consciousness as the bearer of karmic seeds . This places the text within Vasubandhu's Yogācāra period, showing how he moved from critiquing Sarvāstivāda Abhidharma to constructing a distinctively Yogācāra account of causation and karmic persistence. The text is thus a crucial link between the Kośa and the mature Yogācāra works like the Triṃśikā, demonstrating that Vasubandhu's turn to Yogācāra was not a rupture but a development of problems already present in his Abhidharma work.

Vasubandhu argues that bodily and vocal actions are not material substances—not atoms of matter set in motion—but 'informations' (vijñapti) produced by consciousness. A bodily action is the outward expression of a volition, a configuration of the body that 'informs' others of the agent's intention; a vocal action is similarly an audible information. This means that karma is not fundamentally physical but mental: the physical and vocal expressions are the manifest forms of a prior mental event . The argument is designed to show that the materialist account of karma—which treats actions as physical movements that leave physical traces—is incoherent, and that only a consciousness-based account can explain how karmic efficacy persists after the physical action has ceased. The storehouse consciousness is the repository of these mental informations.

The most common misunderstanding is that it is a general treatise on Buddhist ethics, explaining what actions are good and bad and how to live a moral life. It is not. The text is a technical philosophical investigation into the metaphysical mechanics of karma: how an action can produce an effect after it has ceased, what kind of entity a karmic trace is, and whether that entity is physical or mental . It presupposes the ethical framework of Buddhism and does not argue for it; its contribution is to explain how the framework is metaphysically possible. A related misunderstanding is that it is a simple summary of Yogācāra doctrine. It is a polemical work, arguing against specific Abhidharma and Sautrāntika positions, and its arguments are technical and densely reasoned. Readers should approach it as a contribution to Buddhist philosophy of action, not as a moral handbook.