The edge of a map of knowledge is drawn from the side that has already been explored.

The frontier is described by the people standing inside it. What counts as the edge of knowledge, and what lies just beyond, is sketched using the concepts we already have, which means the map’s border reflects our current vocabulary as much as the territory. What we cannot yet conceive of does not appear as a blank space; it does not appear at all.

Be humble, then, about lists of remaining questions, including your own list of what you need to learn. The most important thing missing from your understanding is probably not on it. Reading outside your field, or asking someone from a different background what seems strange about your area, is a way of borrowing another vantage point.