In this context, what does the phrase ''follow upon'' mean? Should I take here the word 'upon'' as ''immediately or very soon after''?
Context:
Everywhere is found a perpetual change of material and mental phenomena. In this way, moment follows upon moment, day upon day, year upon year, life upon life. And so this ceaselessly changing process goes on for thousands, even aeons of years.
Source: Page.7 ''Fundamentals of Buddhism'' by Nyanatiloka Mahåthera