Learning: Importance of foundations

 I've found that a lot of people "know" things, but one you start questioning them deeply they don't really "understand" things. 

To put things in a formal perspective, you can say there's little "connectivity" and "rich graph structure" beneath that single "node". For instance, you might talk to some pop science enthusiast about the hip new discovery in particle physics. He might know all the names: Higgs-Boson, wave-particle duality, whatever. But you start asking questions and it appears that their mental model is basically the same as yours, except with special names for "very small glowy balls". 

Elon Musk says this is not so helpful. He makes sure to build the trunk first, instead of collecting the leaves. Build a core knowledge base -- what is this field actually about? And then, as you accumulate knowledge start building connections, a rich graph structure, involving the foundations, the new knowledge, to external knowledge, whatever. 

If the previous lesson regarding memory was about having the requisite nodes available, this one is about building connections between the nodes.