This work is a philosophical investigation into Vasubandhu's consciousness trilogy, comprised by the Trisvabhāva-Nirdeśa ("Instruction on the Threefold Own-State-of-Being,") and the Vijñaptimātra-Kārikas ("Verses on Consciousness-Occasion,") divided into the Viṃśika-Kārikas ("Twenty Verses") and the Triṃśika-Kārikas ("Thirty Verses.") Although early Indian Yogācāra Buddhism was once non-controversially described as a form of absolute ontological idealism, challengers have urged predominately psycho-epistemological readings of Yogācārin works. However, neither an exclusively metaphysical or exclusively epistemological reading is warranted; the more interesting and difficult case is that these themes are necessarily interwoven throughout the early Yogācāra canon, including the consciousness trilogy. While Vasubandhu's position in the trilogy is indeed idealist and monist, this does not entail a rejection of objectivity. Functions are substituted for substances in ontological discussions. The ālayavijñāna ("storehouse-consciousness") concept is developed so that it can serve the explanatory function of material cause. In this way much apparent logical tension is diffused, and a more complete picture of Vasubandhu's Yogācāra emerges.
