The distinction I have in mind is between knowing the inside of a topic in deep detail — many facts and problem-solving skills — and knowing the structure and context of a topic: essential facts, what problems can be solved by the skilled, and how the topic fits with others.

Studying to learn about everything I recommend that intellectually ambitious students invest considerable time in a mode of study may set off subconscious alarm signals that conflicts with almost instinctive impulses imparted by classroom experience:

Formal education in science and engineering centers on teaching facts and problem-solving skills in a series of narrow topics.

It is true that a few topics, although narrow in content, have such broad application that they are themselves integrative: These include (at a bare minimum) substantial chunks of mathematics and the basics of classical mechanics and electromagnetism, with the basics of thermodynamics and quantum mechanics close behind.

By knowing the outlines of a field, I mean knowing the answers, to some reasonable approximation, to questions like these: What are the physical phenomena? What are their magnitudes? What are their preconditions? How well are they understood? How well can they be modeled? What do they make possible? What do they forbid?

The technologies that may be dead-ends for efforts to construct a self-aware artificial mind could easily be of great value as non-conscious assistants to human minds.