The idea of an autonomous individual.

It is crucial to understand what is meant by “self,” before one is able to realize the all-important “absence of self.” Before we can discover an absence, we have to know what we are looking for. In Mahāyāna, there is a self of persons and a self of things, both presumed habitually by living beings and hence informative of their perceptions. Were these “selves” to exist as they appear because of our presumption, they should exist as substantial, self-subsistent entities within things, or as the intrinsic realities of things, or as the intrinsic identities of things, all permanent, unrelated and unrelative, etc. The nondiscovery of such “selves” within changing, relative, interdependent persons and things is the realization of ultimate reality, or absence of self.

A substantial, self-subsistent entity within beings or things, or the intrinsic reality of things, or the intrinsic identity of things, that is permanent and nonrelative. The Buddha’s teaching, in contrast to that of other spiritual traditions, holds as a key tenet that the presumed existence of such a ‘self’ (in Mahāyāna thought, in things as well as in beings) is habitual but mistaken, and is the basis of suffering and delusion. Its absence (nonself) can be realized by investigation.

Also translated often as “self” or “I.”