"When you reach the top of the mountain, keep climbing." -Zen Proverb
Literally, a dangling pointer is a pointer that points at an object that no longer exists. Figuratively, a dangling pointer is closely related to the idea that we are adaptation executors, not fitness maximizers. To call something a dangling pointer means that it continues to point us in the direction of some behavior or object, regardless of the external state of the world or whether that object is actually good or desirable. Continuing to desire cake after all your caloric needs have been met. Continuing to desire more money after making far more than one could ever spend in a lifetime. Continuing to treat someone with generosity who has repeatedly and consistently taken advantage. These examples are of failing to update or eliminate a dangling pointer despite the environment changing such that they no longer make sense.