Its from "Matter"

Hippense cleared his throat and said, "The type of progress you guys are used to doesn't scale into this sort of civilisational level; societies progress until they Sublime - god-like retirement, if you will - and then others start again, finding their own way up the tech-face. But it is a tech-face, not a tech-ladder; there are a variety of routes to the top and any two civs who've achieved the summit might well have discovered quite different abilities en route. Ways of keeping technology viable over indefinite periods of time are known to have existed aeons ago, and just because something's ancient doesn't mean its inferior."