The unknown is not a single room; learning can reveal how many doors you had not noticed.

Learning does not shrink the unknown in a simple way. Each answer opens onto questions you were not equipped to ask before, so the more you know, the larger and more detailed your ignorance becomes, which is why people well into a subject often feel less certain than beginners. The room turns out to have been a corridor.

If your confidence has gone down as your competence has gone up, that is a sign of progress rather than decline. Measure yourself by the quality of the questions you can now ask, not by the feeling of mastery. And go easy on the beginner’s certainty in others, since most of us pass through it.