Vasubandhu stands out as the great systematizer of Yogācāra, gathering earlier insights and organizing them into a coherent philosophical vision. Through concise works such as the *Viṃśatikā* (“Twenty Verses”) and *Triṃśikā* (“Thirty Verses”), he articulated the “consciousness-only” (vijñapti-mātra) perspective with unusual clarity, arguing that what appear as external objects are in fact representations within consciousness rather than independently existing entities. This view is not a mere abstraction; it is grounded in careful reflection on dreams, illusions, and the shared world of experience, and it serves to undermine naïve realism while preserving the practical utility of appearances. In this way, Yogācāra becomes a disciplined exploration of how mind constructs the duality of subject and object.

A central feature of Vasubandhu’s contribution is his detailed analysis of the eight consciousnesses. He delineates the five sense consciousnesses, the mental consciousness (mano-vijñāna), the afflicted mental consciousness (kliṣṭa-manas), and, most crucially, the storehouse consciousness (ālaya-vijñāna). This ālaya-vijñāna functions as a subtle, underlying flow in which karmic seeds (bīja) are deposited, later ripening into future experiences. By appealing to this model, Vasubandhu offers an account of karmic continuity and rebirth that does not rely on a permanent self, showing how delusion and self-grasping arise from the interaction of these layered modes of awareness.

Closely related to this is his refinement of the doctrine of karmic seeds and the transformation of consciousness. The seeds stored in the ālaya-vijñāna condition perceptions, emotions, and habitual patterns, shaping the world that appears to each being. Yet these same structures are not fixed; through spiritual practice, the consciousnesses can undergo a profound transformation (parāvṛtti), in which afflictive patterns are transmuted into wisdom. In this light, Yogācāra is not merely a theory about mind but a map of how distorted cognition can be gradually purified.

Vasubandhu also elaborates the doctrine of the three natures (trisvabhāva): the imagined, the dependent, and the perfected. This scheme explains how conceptual construction overlays a falsely imagined duality onto a dependently arisen flow of experience, while the perfected nature points to the way phenomena are when free from such projections. His analyses of perception and error, together with his integration of Yogācāra insights into the rigorous Abhidharma style of analysis, gave later Buddhist traditions a powerful set of tools for understanding both the bondage of ignorance and the possibility of liberation. Through these contributions, Yogācāra emerges as a subtle path of examining consciousness so that its own fabrications can be seen through and released.