See-also: keep your identity small, by Paul Graham.
1. Note that "quote" isn't in quotes because it isn't a quote. See-also wiki or this blog post. When I say it, I mean that it is no good relying on your excellence alone. If you try to do things - solve puzzles, do real work, athletics - and repeatedly fall short of what you were aiming for, but tell yourself each time that was only a trial, you could do better but didn't actually try your best that time, then when it comes to the "real thing" you will fail as well. The converse, of course, is that you can observe people's "excellence" from their everyday lives, you don't need to wait until they try some difficult test.
2. That wiki page also contains the nice "Those who can, do. Those who understand, teach" which is a paraphrase of A's "We regard master-craftsmen as superior not merely because they have a grasp of theory and know the reasons for acting as they do. Broadly speaking, what distinguishes the man who knows from the ignorant man is an ability to teach, and this is why we hold that art and not experience has the character of genuine knowledge (episteme)--namely, that artists can teach and others (i.e., those who have not acquired an art by study but have merely picked up some skill empirically) cannot."
3. That his physics was crap doesn't mean I have to diss all his stuff.
4. The picture is irrelevant. I'm not slaying any great dragon here. I just liked it. See Bernat Martorell for the full image. h/t Bibliothèque Infernale.
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