There is some truth to that quote, namely that becoming effective at looking things up is a big productivity booster. But there is no productivity booster as l

There is some truth to that quote, namely that becoming effective at looking things up is a big productivity booster. But there is no productivity booster as large as knowing exactly how to do something without needing to look it up. This is almost by definition the level of mastery that comes from significant practice / experience. I've noticed that some of the very smart people I've worked with for years did not ever really achieve mastery of their language or tools, and I think that's at least partially because they didn't care to take the time to try and figure things out without looking them up, and thus the inner workings of things remained inscrutable to them.