Vasubandhu worked first as an Abhidharma scholar of the Sarvāstivāda-Vaibhāṣika school, producing the "Abhidharmakośa," an encyclopedic verse summary and prose commentary on Buddhist scholastic metaphysics that also subjected Vaibhāṣika orthodoxy to Sautrāntika-leaning criticism. After his turn to Mahāyāna Buddhism, traditionally attributed to the influence of his half-brother Asaṅga, he became a founding systematizer of Yogācāra philosophy, arguing that the experienced world is a construction of consciousness rather than a mind-independent external reality.
Intellectual setting
Vasubandhu worked within the Buddhist monastic and scholastic culture of Gandhāra and Kashmir under Kushan and Gupta-era patronage, a period of vigorous debate among Sarvāstivāda, Sautrāntika, and emerging Mahāyāna schools. His shift from Abhidharma orthodoxy to Yogācāra, and his rivalry with the Vaibhāṣika master Saṅghabhadra, are preserved in the biographical traditions recorded by the Chinese translator Paramārtha.
Key ideas
Vijñaptimātra (representation-only)
In short treatises such as the "Viṃśatikā" and "Triṃśikā," Vasubandhu argued that the perceived world of objects is exhaustively explained by the ripening of "seeds" (bīja) stored in an underlying store-consciousness (ālayavijñāna), so that no external material substrate need be posited to account for ordinary experience.
Momentariness and the critique of Vaibhāṣika realism
In the "Abhidharmakośa," Vasubandhu catalogued and criticized rival Buddhist positions on causation and time, defending a rigorous doctrine of momentary existence (kṣaṇikatva) against the Vaibhāṣika thesis that the constituents of experience (dharmas) exist substantially across past, present, and future.
Legacy
The "Abhidharmakośa" became the standard scholastic textbook of Buddhist philosophy across India, Tibet, and East Asia, while Vasubandhu's Yogācāra treatises, transmitted and commented on by Sthiramati, Dharmapāla, and Xuanzang, founded the Yogācāra ("Consciousness-Only") tradition that shaped Buddhist epistemology and psychology for over a millennium.