Twenty Verses (with the Thirty Verses)

Two short verse works central to the Yogācāra school. The Twenty Verses, with Vasubandhu's own prose commentary, defend the thesis that what we experience is cognition only (vijñapti-mātra), without external objects. Vasubandhu answers four objections: if there are no external objects, why are experiences fixed in place and time, shared by many, and causally effective? Dreams show fixed places and real effects; the shared visions of beings in the hells show agreement without objects. He then argues that atoms cannot combine into extended things without either having parts or collapsing into a single point, so the realist's external world is incoherent. The Thirty Verses give the positive system: the storehouse consciousness (ālaya-vijñāna), the afflicted mind, the six active forms of awareness, and the three natures, imagined, dependent and perfected. Whether this Vasubandhu also wrote the Abhidharmakośa is debated.

In a few pages it gives one of the sharpest arguments for idealism in any tradition, and comparing it with Berkeley shows how differently two idealisms can be motivated.