Danny Moloshok / ReutersElon Musk.You can attach a whole range of titles to Elon Musk's name - engineer, designer, or chief executive, to name a few.
But he wouldn't be any of those things if he wasn't ridiculously good at learning.
During the course of his career, Musk has mastered online payments, rocket flight, and electric car manufacturing, plus a host of other subjects.
In Monday night's Reddit AMA, user aerovistae asked Musk how he learns so much so fast.
Musk's reply was instructive:
I think most people can learn a lot more than they think they can. They sell themselves short without trying.
One bit of advice: it is important to view knowledge as sort of a semantic tree -- make sure you understand the fundamental principles, ie the trunk and big branches, before you get into the leaves/details or there is nothing for them to hang on to.
In other words, knowledge has a logical structure to it, and you need to understand the foundations before moving to the extremities.
Musk's emphasis on "fundamental principles" mirrors another healthy habit of mind he adheres to: first principles thinking.
Musk says that with first principles, "you boil things down to the most fundamental truths … and then reason up from there."
The approach goes all the way back to Ancient Greece, which was the start of Western civilization's attempts to systematize knowledge.
Over 2,300 years ago, Aristotle said that a first principle is the "first basis from which a thing is known" and that pursuing first principles is the key to doing any sort of systemic inquiry - whether in philosophy, as he did, or in business, as Musk does.
In other words, you have to get to know the tree's trunk, then branch out from there.