 Augustine’s answer to this riddle is that what we are measuring, when we measure the duration of an event or interval of time, is in the memory. From this he derives the radical conclusion that past and future exist only in the mind. While not following Augustine all the way to the mind-dependence of other times, we can concede that the perception of temporal duration is crucially bound up with memory. It is some feature of our memory of the event (and perhaps specifically our memory of the beginning and end of the event) that allows us to form a belief about its duration. This process need not be described, as Augustine describes it, as a matter of measuring something wholly in the mind. Arguably, at least, we are measuring the event or interval itself, a mind-independent item, but doing so by means of some psychological process.