This fundamental Buddhist doctrine proposes that all compound things are impermanent and transitory despite any appearance of consistency or permanency they might have. As the Buddha taught, “All conditioned things are impermanent’ — when one sees this with wisdom, one turns away from suffering”.

Aniccā is one of three fundamental doctrines in Buddhism with the other two being anattā (no permanent soul or Self) and duḥkha (suffering).

Buddhists maintain that an erroneous belief in permanence counteracts one’s ability to attain true perception of reality and therefore an appropriate understanding of the human predicament. This predicament is the person’s entrapment within the endless cycle of death and rebirth (saṃsāra) from which he or she seeks to escape by attaining nirvāṇa or enlightenment.

Through an industrious application of the Eightfold Path, which is the fourth of the Four Noble Truths, the truth of impermanence is discoverable and will free one from the negative sentiments of hate and greed.

At the center of the Buddha’s teachings is duḥkha, which is the belief that life is “suffering”, also sometimes referred to as “stressful” or “unsatisfactory”. This is caused by a powerful craving or “thirst” that is never satisfied. This craving emerges from ignorance concerning the true nature of reality and can quickly lead to envy, anger, greed, and even violence. However, recognizing that aniccā characterizes everything is one step along the path of spiritual progress toward enlightenment.

Attaining liberation or enlightenment also requires translating this understanding into practice, often so in a meditative way, by reducing one’s attachment to a world of transience. To grasp and hold firm to phenomena within a transient world only leads to further frustration and suffering instead of happiness. 

A noteworthy equivalent of the Buddha’s doctrine of impermanence in the Ancient Greek world is in Heraclitus of the sixth century BCE. Heraclitus proposed that things are in constant, universal flux, and therefore transient. As Plato reports, Heraclitus claimed that one “could not step twice into the same river”.