Picture a very swift torrent, a river rushing down between rocky walls. There is a long, shallow bar of sand and gravel that runs right down the middle of the river. It is under water. You are born and you have to stand on that narrow, submerged bar, where everyone stands. The ones born before you, the ones older than you, are upriver from you. The younger ones stand braced on the bar downriver. And the whole long bar is slowly moving down that river of time, washing away at the upstream end and building up downstream.
Your time, the time of all your contemporaries, schoolmates, your loves and your adversaries, is that part of the shifting bar on which you stand. And it is crowded at first. You can see the way it thins out, upstream from you. The old ones are washed away and their bodies go swiftly by, like logs in the current. Downstream where the younger ones stand thick, you can see them flounder, lose footing, wash away. Always there is more room where you stand, but always the swift water grows deeper, and you feel the shift of the sand and the gravel under your feet as the river wears it away. Someone looking for a safer place can nudge you off balance, and you are gone. Someone who has stood beside you for a long time gives a forlorn cry and you reach to catch their hand, but the fingertips slide away and they are gone.
There are the sounds in the rocky gorge, the roar of the water, the shifting, gritty sound of sand and gravel underfoot, the forlorn cries of despair as the nearby ones, and the ones upstream, are taken by the current. Some old ones who stand on a good place, well braced, understanding currents and balance, last a long time. A Churchill, fat cigar atilt, sourly amused at his own endurance and, in the end, indifferent to rivers and the rage of waters. Far downstream from you are the thin, startled cries of the ones who never got planted, never got set, never quite understood the message of the torrent.