Avirbhava and Tirobhava are philosophical terms in Hindu religion for sensual and non-sensual experience. Avirbhava and tirobhava are two technical terms in the Samkhya and Yoga schools of Hindu philosophy. The former indicates the experiential state of any object of experience, i.e., a state in which an object can be experienced through the agency of a sense organ, such as the sense of sight, touch, smell, taste or sound. The latter indicates a state in which an object cannot be so experienced; it is said to be tirohita, or hidden.
According to Parinamavada, which is a fundamental
pre-supposition of Samkhya and Yoga schools, every object in the world, except
the multitude of selves (atma, jiva or purusha) is constituted of three gunas,
namely, sattva, rajas and tamas. A very basic characteristic of these gunas is
that they perpetually undergo modification or change, which is called parinama.
This characteristic of constant modification inheres in all the objects which
are constituted of the tree gunas. Thus, an object which we can experience does
not at any time cease to exist. Its experience is an eternal quality, because the
three guans which together constitute any object are eternal. But this does not
mean that the object may be experienced eternally. It can be experienced only
when it is in the state of avirbhava, and it will not be possible to experience
it when it is in the state of tirobhava. The words used by Patanjali in Yoga Sutra for avirbhava are pradurbhava and udaya; he uses the work kshaya for tirobhava
(III. 9, 11). The self is ever free from any parinama, as it is devoid of the three
gunas.