Real expertise and knowledge is gained by doing both. Just interacting with things gets you to a certain level, but if you want to go beyond that, you need to i

Real expertise and knowledge is gained by doing both. Just interacting with things gets you to a certain level, but if you want to go beyond that, you need to interface with the problem at an abstract level. Anyone with actual expertise in a complex, intellectual subject does both. Mental models are extremely important, even if you already understand a subject well. Mental models, when they're good, tend to deal with the limits to knowledge, and reasoning in the absence of perfect information. Experts often do these things implicitly in their field of expertise. Naming and abstracting these things allows people to see them as the general principles that they are, and apply them more readily in other domains.