Cached Thoughts are ideas, attitudes and beliefs that a person has internalized on some past occasion, and hasn't re-evaluated since then. The name references the concept of a cache in computing: a component storing data that has been calculated or retrieved once, so that it is quickly available without needing to be recalculated or re-retrieved.
In modern civilization particularly, no one can think fast enough to think their own thoughts. If I’d been abandoned in the woods as an infant, raised by wolves or silent robots, I would scarcely be recognizable as human. No one can think fast enough to recapitulate the wisdom of a hunter-gatherer tribe in one lifetime, starting from scratch. As for the wisdom of a literate civilization, forget it.
But the flip side of this is that I continually see people who aspire to critical thinking, repeating back cached thoughts which were not invented by critical thinkers.
-- Eliezer Yudkowsky, Cached Thoughts