Ask people if they’d change their mind given new evidence, and most will say yes. Put them in the situation, and the mind often defends stability over accuracy, especially when a belief has fused with identity, tribe, or moral status.

Memes are units of cultural transmission, Dawkins’s analogue to genes, that hop from brain to brain by imitation. They can harden into norms, identities, and shared fictions, recruit emotion and tribal defense, and behave like agents in how people protect or spread them.