Knowledge is of two kinds: anubhava, reached through evidence, which may be both true (when it is prama) and false, but which is always something new, previously unattained; and smrti or memory-knowledge which, however, is not something new. In the persisting cognition of the same object, there is a single unchanging presentation illuminated by, i.e., subsumed under the form of the self. Such a persisting determinate cognition (as distinct from the presentation) ceases, however, when it is contradicted by another cognition standing on stronger evidence.

The theory of the persistence of the presentation fits in with the peculiar realism of Vedanta which demands an intuition-continuum for every grade of abstract thought. The necessary thought of the identity between a presentation and an idea must have its basis in the continuity of the presentation in some real medium.

Besides, as knowledge is viewed in Vedanta from the standpoint of the self as spontaneity and not from the empirical standpoint, the logical activity of the self (and not the presentation) is taken to determine how long a mode of cognition can be said to endure as one and the same; it is said to cease only when contradicted.