Imagine : all this existence and time is the unrelenting activity of billions of people; the length of their lives and their actions are culminating and progressing history. They have sprung into existence in this current time and space and are enacting an energy that causes a progressional movement of activity which effects a greater causality.
We are plunged into this life, as a force, moving together in one direction, in a stream of time. there are many different forces coming in and out of the stream, but because there are more here than there are coming out the stream keeps flowing- time keeps going.
History is a stream of humanity; beings come in, take part of the activity then leave, and so on and so on