"Trying to synthesize a personal art of rationality, using the science of rationality, may prove awkward: One imagines trying to invent a martial art using an abstract theory of physics, game theory, and human anatomy. [...] Therefore we must connect theory to practice."

This is a key realization that strikes me now. Merely reading the sequences or LW posts and absorbing the wisdom of others is insufficient. Replacing old cached knowledge with new doesn't enable a person to advance their art.

To get the most out of a desire to change one's thinking, one has to actively put the theorems to use. The body of accumulated knowledge has to be tested and extended. Feynman's shock at the fragile knowledge of others "learned by rote" appears to me to be similar to Yudkowsky's observation here.

I find this to be the difficult part of re-reading the Sequences. The first time through is full of hard revelations and new ideas. Many of these become adopted, but not fully understood. Successive readings are opportunities to slowly break things down and build a functioning understanding of the principles, but you also have to go out and actually apply the knowledge to internalize it. (I have been passive in that regard and it bothers me.)