Time, and the categories of time, like the past, the present, and the future, are important topics to study on the Buddhist path. This is because, for the purification of karma, we need to understand the nature of past destructive actions that we have committed and their future karmic results. The Buddhist systems do not speak in terms of the sequence of past, present, and future as conceptualized from a Western point of view, but rather analyze in terms of the sequence of the not-yet-happening, present-happening, and no-longer-happening of something. A period of time is a nonstatic imputation phenomenon on the mental continuum of our moments of cognition during the interval between the experiencing of two sequential events, such as committing a karmic action and experiencing the ripening of its results.