Evaluating evidence accurately requires metacognitive skills that incompetent individuals lack, preventing them from recognizing their own cognitive limits.

To judge evidence well, you must know what you do not know. This requires metacognition—the ability to monitor your own thinking. Psychologists Justin Kruger and David Dunning showed that those lacking skills in a task also lack the ability to evaluate their own performance. Without epistemic humility, amateurs confidently misinterpret complex data. True experts, however, calibrate their confidence. They match their certainty strictly to the strength of the available proof.