One interesting thing about beliefs in a changing world is how you deal with contradictory beliefs.

I see "beliefs" as an optimisation that avoids having to return to first principles for every single decision.

That speeds things up, but is obviously dangerous.

Sometimes it's possible to have two beliefs that contradict each other. Usually this means they need reevaluating, but sometimes it means there is context in which each is true.

Reasoning in the face of contradictory beliefs is one of the most interesting things about "knowledge", and something that humans can do surprisingly well - at least until we realise we are doing it.