The Refutation of Buddhist Idealism

The Buddhist claim that consciousness consists of momentary discrete events — each arising and passing away, with no persistent subject to connect them — is, for Shankara, internally incoherent. If there is no continuous subject, there can be no memory: for a memory to be a memory of my past experience rather than merely a cognition of some past event, there must be an identity between the rememberer and the experiencer that persisted through the interval. The Buddhist can account for causal continuity between moments but not for the personal identity that memory requires. Without a continuous self, the entire enterprise of liberation becomes meaningless: who would be liberated, and from what, if the being who practises liberation and the being who achieves it are numerically distinct?

Against idealist Buddhism's claim that there is no external world — that all apparent objects are merely internal representations with no external referent — Shankara offers a pragmatic and phenomenological argument. The experience of objects as external, as resistant to manipulation, as persisting when not perceived, is a bedrock datum of ordinary experience. An idealist theory that explains this datum away by appeal to a complex theory of internal representations that happens to mimic external reality violates the epistemological principle that direct experience takes precedence over theoretical inference. Moreover, the idealist's own reasoning presupposes a distinction between valid and invalid cognitions — between accurate representations and illusions — and this distinction is only intelligible if there is something external to the cognition by which its accuracy is assessed.

The disagreement between Shankara and Buddhist idealism should not obscure the extent to which they share premises. Both deny the ultimate reality of the individual self as ordinarily conceived; both regard the phenomenal world as in some sense lacking ultimate reality; both locate liberation in a transformation of consciousness that dissolves the normal subject-object structure of experience. Shankara's charge is not that Buddhism goes too far in dissolving ordinary reality but that it does not go far enough: the Vijnanavadin dissolves the external world but leaves consciousness as a series of momentary events, missing the unchanging witness-awareness that alone can ground the appearance of either the internal or the external. The final ground is not a flow of consciousness but the still, self-luminous absolute in which all flows occur.

Shankara's critique of Buddhism runs through multiple sections of the Brahmasūtra Bhāṣya, with the most concentrated treatment in his discussion of sutra II.2.18–32. The relationship between Advaita and Mahayana Buddhist philosophy has been extensively debated in modern scholarship — some arguing for deep Buddhist influence on Shankara, others for fundamental incompatibility.