Some years after the birth of Asanga, his remarkable mother, Prakashashila, married a learned Brahmin and gave birth to two sons. The eldest, Vasubandhu, was born around the time of Asanga's ordination as a Buddhist monk. Unlike Asanga, whose father was a Kshattriya, Vasubandhu was raised a Brahmin and instructed in the three Vedas, but when he attained maturity he decided to become a Buddhist monk. By then his brother Asanga was far away, already formulating and teaching the Mahayana doctrines that came to be known as the Yogachara. When Vasubandhu received his own ordination at Nalanda, he studied the Tripitaka, the Three Baskets of teachings of the non-Mahayana schools, of which the Theravada is the only surviving representative. Whilst his remarkable brilliance and penetrating insight rivalled those of his brother, he did not follow Asanga's path of intense solitary meditation.
Instead, he journeyed to Kashmir, where he came under the beneficent influence of Samghabhadra, who encouraged him to master the teachings of the eighteen non-Mahayana schools as well as all the branches of exoteric knowledge. Taranatha wrote that Vasubandhu also extensively studied the six systems of Hindu philosophy and mastered its methods of debate. Upon completing his studies he returned to Nalanda, according to Bu-ston. Taranatha adds that he lived for a number of years in Magadha, the literary home of the Pali tongue. While residing in Magadha, Vasubandhu read his brother's Yogacharabhumi but found the Mahayana doctrines too recondite. He doubted the widespread belief that Asanga had actually received instruction from the Bodhisattva Maitreya, and tradition holds that he exclaimed: "Alas! Asanga meditated for twelve years in the forest, but instead of attaining success he has composed a work fit to be an elephant's load." His sardonic remarks came to the ears of Asanga, who was not offended, but simply said, "It is time to convert him."
Asanga devised a thoughtful strategy and trained two monks, having each one memorize a specially chosen Mahayana sutra. Then he sent both to call upon Vasubandhu. In the evening the first monk recited his sutra, outlining the Mahayana standpoint. Vasubandhu saw the logic of the system but wondered if it might not encourage indolence. In the morning, however, the second monk recited the Dashabhumisutra, which sets forth the ten stages of the Bodhisattva path as the fusion of theory and practice. Vasubandhu was overwhelmed. Great sadness and regret came upon him for the disrespect he had previously shown for his brother's path. He contemplated cutting out his tongue in penance for his disparaging remarks, but the surrounding monks restrained him from rash self-injury and insisted that he seek his brother's advice on how best to atone for his wrong. Vasubandhu went to Asanga, embraced the Mahayana and recanted his discourteous remarks. Asanga instructed Vasubandhu to refrain from harming himself and to do penance by applying his formidable skills and eloquence to learning and teaching the Mahayana doctrine. Asanga taught Vasubandhu sutra and mantra, and his willing disciple soon mastered the sacred texts and became proficient in meditation. When debating with his brother, Vasubandhu was quick-tongued but Asanga usually won. Others saw this as a paradox, but Asanga explained that he was slower because he borrowed his ideas from Maitreya, whereas Vasubandhu worked them out on his own. It is said that Vasubandhu thoroughly learnt each sutra by heart after listening to Asanga recite it only once. When Vasubandhu entered the Mahayana, a great number of monks joined him. He assisted Asanga for a number of years and helped spread Yogachara Teachings.
Upon the death of Asanga, Vasubandhu is said to have become the Upadhyaya, chief preceptor, of Nalanda. He spent most of the remainder of his life at Nalanda, where he performed his duties with vigour and precision. He produced more than fifty commentaries on Mahayana and other sutras, composed expositions of Asanga's works and wrote a number of original treatises. He was an effective dialectician and eloquent expositor of Buddhadharma, and he conscientiously performed the daily duties of a teacher at Nalanda. Every morning he would recite an appropriate text and expound its meaning. Throughout the day he would advise and counsel younger monks, guiding them by his own example in discharging with great care the duties of a monk. In the evenings he would listen to debates and resolve differences of standpoint by clearly summarizing the essence of the doctrine. Taranatha declared that he was visited by his deity in deep sleep and thus received instruction in arcane spiritual wisdom.
Once he accepted an invitation to discourse in Gauda, east of Nalanda, and while he explained the sutras there, deities showered golden flowers upon the attentive citizenry. On another occasion he visited Odivisha, and during a short period of relaxation he revealed no less than five separate clusters of precious gems. When people showered him with gifts, wise monks noticed that nagas, yakshas and other non-human intelligences joined them in paying homage to him. On one occasion, when an uncontrollable fire broke out in Rajagriha, Vasubandhu extinguished it with an invocation, just as he once brought a plague in Janantapura under control through a mantram. It is also said that his vast vidyamantra, knowledge of sacred syllables, allowed him to control ageing and determine the time of his own death. Late in life he was called to Nepal to restore the purity of the teaching. After reorganizing the Buddhist community there, he bade farewell to his disciples, uttered a particular mantram thrice backwards, and died. A caitya was erected in his memory in Nepal. He had lived between eighty to a hundred years, the majority of them spent in disseminating Yogachara teaching. According to Taranatha, his death was "the setting of the sun of the Dharma for the time being", and Paramartha added that "all who study the Mahayana and the Hinayana in India use the productions of Vasubandhu as their text-books".
Vasubandhu laboured to make Asanga's teaching accessible to a wide range of minds. Perhaps his finest surviving work is the Trimshikakarikaprakarna (Treatise of Thirty Verses), a succinct digest of Yogachara thought. Vasubandhu announced the root perspective of Yogachara in the first verse of the text: conceptions of self (Atman) and conceptions of elements of reality (dharmas) do not entail that either exist. Rather, their inherently fictitious character gives rise to the whole phenomenal world. As mere phenomena, they arise as the manifestation of ceaselessly changing states of consciousness. The kinds of consciousness capable of manifestation fall naturally into three types distinguishable by function: Alayavijnana is the universal storehouse of ideation, characterized by the maturation of its activity over time; Manas is that consciousness which is capable of cognition and deliberation; Manovijnana is the coordinating centre of the five senses, each of which involves a kind of consciousness commensurate with sensation. There are in sum three types and eight kinds of consciousness.
Alayavijnana, the eighth and highest consciousness, is sometimes called vipakavijnana, or retributive consciousness, because its fruits (karma) ripen at different times. It is also called sarvabijakavijnana because it carries within itself all the bijas or seeds which will sprout as karmic effects. Alayavijnana is, therefore, the repository of the results of action, the treasury of karma yet to be expended. Alayavijnana cannot be fully defined because its basis – and therefore its contents – cannot be entirely known. Nor can it be assigned place or location since it is the basis of all other kinds of consciousness. Its root powers of perception and discrimination must remain forever a mystery. It can, however, be associated with the five caittas or attributes: sparsa (mental contact), manaskara (attention), vedana (sensation), samjna (conception) and chetana (volition). It is always associated with upeksa, the sense of indifference. Manifesting itself like a relentless torrent, it is renounced only by the Arhat who attains Nirvana.
Manas, the seventh consciousness, evolves from Alayavijnana, which it takes as its basis and support because the universal storehouse is the true object of manasic consciousness. Manas is characterized by cognition and intellection, and is invariably accompanied by the four kleshas or sources of affliction and delusion: atmamoha (self-delusion), atmadrishti (belief in a self), atmamana (self-conceit) and atmasneha (love of sell) – as well as by the five caittas. Since Manas operates in the realm in which beings are born, it ceases in the Arhat. It is paralysed in the higher states of meditation on the transcendental path. If Alayavijnana is thought of as neither defiled, obscured nor defined, Manas is undefined but defiled. Neither 'good' nor 'bad' can be predicated of either of them, as they can of the remaining six forms of consciousness.
Together, these remaining kinds of consciousness constitute Manovijnana, the third evolute of mind, distinguished by perception and discrimination of objects. In addition to their association with the caittas and the kleshas, they are also involved with special and secondary forms of both. These special caittas include chanda (desire), adhimoksha (resolve), smriti (memory), samadhi (meditation) and prajna (discernment). Beneficial caittas encompass shraddha (belief), hri (shame) and apatrapa (integrity), as well as alobha (non-covetousness), advesa (non-anger), amoha (non-delusion), virya (diligence), prashrabdi (mental composure), apramada (watchfulness), upeksa (equanimity) and avihimsa (harmlessness). The kleshas appear in Manovijnana and the five forms of sense-consciousness as covetousness, anger, delusion, conceit, doubt and false views, as well as the twenty secondary troublesome mental qualities: fury, enmity, hypocrisy, vexation, envy, stinginess, deception, fraudulence, harmfulness, pride, shamelessness, lack of integrity, restlessness, torpor, unbelief, indolence, idleness, forgetfulness, distraction and thoughtlessness. Remorse and drowsiness are indeterminate mental qualities because they carry no moral valence, and vitarka and vicara, reflection and investigation, can be beneficent or maleficent, depending upon the way they are used. Whilst the five sense-consciousnesses manifest in various ways determined by cause and condition, Manovijnana is always active except in beings who have no objective thoughts, either because they have transcended them because they are deep in meditation beyond thought, or they are mindless.
Once Vasubandhu had shown that consciousness manifests in two ways – as perception or as the object of perception – he drew the unavoidable conclusion that neither Atman (a separate and permanent self) nor dharmas (independent elements of reality) exist. Thus, the whole of manifestation is chittamatra, merely consciousness. Vasubandhu did not absolutize this fundamental formulation any more than his brother Asanga did, since he understood that rigid judgements arise too readily from restrictive and dogmatic conceptions of consciousness. Vasubandhu denied the independent reality of the external world but just as vigorously rejected views which made the universe the subjective fantasy of individuated objective mind. As an objective idealist, he explained how mind gives rise to the kaleidoscope of manifestation.
Since Alayavijnana contains all bijas or seeds, from time to time different kinds of transformation occur, and since dharmas intersect and conjoin, distinctions are engendered which can be perceived, recognized and sorted in diverse ways. The seeds of previous deeds manifest as karma, that aspect of apprehension in which results are the objects of perception. At the same time, the capacity for further conception is brought to what is already thus conceived. Like all other action, both conceiving and conceived leave bijas which will sprout in the future. Even as previous seeds come to fruition, new seeds are deposited which will eventually bear fruit of their own. The inertial process of reduplication is reflected in parikalpitasvabhava, the self-reproductive imagination. What is imagined has no inherent nature of its own. The nature of all things is either paratantra, dependent on others, or parinishpanna, ultimate reality. Dependent nature consists of discriminations and conceptions which are themselves the result of causality and conditionality. Ultimate reality is forever free from any degree of dependence, and therefore it is free of the operations of the objectivizing imagination. The nature of ultimate reality cannot be said to be either the same as or different from the nature of dependence on others, just as impermanence is neither the same as nor different from impermanent dharmas. This means that one who has not directly perceived the nature of ultimate reality cannot perceive the nature of dependent origination.
Vasubandhu used his terse discussion of the nature of existence as the basis for an explanation of the triple aspects of nihsvabhava, non-existence, a teaching intimated by the Buddha in his statement that dharmas have no self-nature. The first aspect is lakshananihsvabhava, non-existence in respect to appearances, for all distinguishable characteristics are dependent products of the imagination and have no existence independent of it. The second is utpattinihsvabhava, non-existence in respect to innate nature or origination, since even origins are the products of mental discrimination. The third is paramarthanihsvabhava, non-existence in respect to absolute truth. This is far removed from anything based on objectivizing imagination, where the conceptions of Atman and dharmas arise. Dharmaparamartha, the supreme truth about all dharmas, is bhutatathata, absolute reality, ever immutable and therefore always abiding in its own nature. And this is vijnaptimatrata, the true nature of consciousness itself, the state sometimes referred to as 'Mind-only'. Consciousness transcends even the subtlest distinction of subject and object, perceiver and perceived. Patanjali spoke of the Spectator without a spectacle.
Vijnaptimatrata is the highest consciousness, beyond the scale of individuation, differentiation and degree, where consciousness knowingly abides in itself. It sows no seeds and therefore has no harvest to reap. In itself consciousness dwells outside of time and events, free of action and reaction. But until consciousness abides in its true nature, the dual power of apprehension – conceiving and being conceived – will exert itself and mind will be ensnared by attachment and drowsiness. So long as an individual perceives any object as an object (even if he believes that it is chittamatra, only consciousness), he is not really residing in vijnaptimatrata, for the eight forms of consciousness are still active. If, however, he surveys the realm of objects without even conceiving the idea of an object, his wisdom is that of vijnaptimatrata, because both object and its apprehension are absent.
This is pure dhatu, undefiled, without obscuration, devoid of parameters, inconceivable and incomprehensible, yet both intrinsically good and enduring. This transcendental ground of consciousness and being is undivided by distinctions or degrees, and having no internal or external relations, it is called bliss. In that holy unconditioned ground, the enlightened being abides in vimuktikaya, the body of emancipation.
Asanga and Vasubandhu were always considered together, not just because they were brothers and equally articulate spokesmen for Yogachara thought, but owing to their remarkable complementarity. Asanga turned inward through rigorous meditation and expounded what he had discovered and verified by direct inner experience. Vasubandhu saturated himself in the philosophies of the eighteen non-Mahayana schools and in his brother's own teaching. He turned outward, seeking to explain to others in comprehensible terms the heart of Yogachara doctrine. He wrote careful analyses of differing viewpoints within and outside the Buddhist tradition, and taught and debated wherever and whenever he was needed. Taranatha wrote that there were sixty thousand Mahayana monks in India at the time of his death, a tremendous increase from the time of Asanga just a few years before. Bu-ston reported that Asanga confided to Vasubandhu that he had been drawn to the philosophical life in all his five hundred immediately previous incarnations. Not surprisingly, when these luminous dialecticians of the divine departed from the earth, it was said that the sun of the Dharma had set for the time being.