I think we are talking about different meanings of "understand". You seem to be using the general meaning -- any expert in a field, given enough time and dedica

I think we are talking about different meanings of "understand". You seem to be using the general meaning -- any expert in a field, given enough time and dedication, can gain understand both the high level complexity and the individual components of a complex system; I agree with you here. But the sort of understanding I'm referring to, and what I believe the author is referring to, is a comprehensive, infinitely detailed understanding -- the sort of understanding of OS X APIs after internalizing 5000+ pages of reference. I think this sort of "complete" understanding is not what we mean when we say a expert has an excellent understanding of a subject; instead, when we mean that that expert can work knows what is important. For example, you could be an expert (and have an excellent grasp of the material) of some programming language, but if someone asked you about the exact name of a rarely used library call, you might not know it off the top of your head. You would know where to look it up, and you would know how to use it, and you would know that that library call exists, but you wouldn't recall the exact name. I think many people can obtain these expert understandings of complex systems, but that's not what the author is referring to (or if he is, then I think his argument is unsound because no one would approach gaining an expert understanding of OS X by reading 11,000 pages of reference material). The author is talking about a unnecessarily detailed "complete" understanding in which you know everything about the system.