Anicca, impermanence in Pali, is the Buddhist teaching that every conditioned thing, physical and mental alike, is in constant flux, arising and passing away without ever remaining fixed for even a moment. Buddhist philosophy names it as the first of the three marks of existence, alongside dukkha, suffering, and anatta, the absence of a permanent self, and treats recognizing impermanence as one of the earliest and most necessary steps on the path toward enlightenment. The teaching applies without exception. A human body moves through childhood, youth, maturity and old age, never the same from one stage to the next, and Buddhist analysis extends the same observation down to the level of individual mental events, described as arising and dissolving moment by moment rather than persisting as a continuous, unchanging stream. Nothing is exempted from this, including the very sense of a stable, continuous self that ordinary experience seems to present; what feels like one continuous person is, on this account, a rapid succession of momentary, conditioned states, each dependent on the ones before it and giving way immediately to the ones after. The teaching is meant to be observed directly through meditation rather than simply accepted as a proposition, and the direct, experiential recognition of impermanence is treated across Buddhist traditions as a decisive turning point in a practitioner's progress.