Let us, as a point of departure, agree that there is a world. That outside this window behind me things are happening. A child plays; magpies roost briefly in the oak beside the house opposite before taking off for somewhere else. Beyond that again, the river, trees, fields, distant hills all do whatever it is they do. Invisible stars radiate, obliterated, for now, by the sun. And beyond that?
Our sense of time, of its duration, is so circumscribed that we cannot, except under the most extreme circumstances, a volcano erupting, for example, notice the flow of stone, the river’s stillness.
Heraclitus was wrong, interestingly so, but wrong none the less; it’s not that you cannot step into the same river twice, it’s simply that we haven’t learned to wait long enough. Most likely we never will. We operate within the limits of our capacities, and our capacities are more limited than we know.