Epistemic closure is like a game where you have to find clues to solve a mystery. Imagine you are playing this game and you have a set of clues, but you can only use those clues to solve the mystery. You cannot consider any other information that may be useful.
Now, let's say another player comes along and gives you some additional information that could help you solve the mystery. Epistemic closure means that you wouldn't be willing to consider this new information because you have already decided that you can only use the original set of clues.
In simpler terms, epistemic closure means that you only believe what you already know and refuse to consider any new evidence or information that could challenge your beliefs. It's like having blinders on and only seeing the things directly in front of you, while ignoring everything else. This can be a problem because it can prevent you from learning new things and making better decisions.