I've been struggling with this concept in the context of teaching someone web development. There's just <i>so much</i> you "have" to know and it all seems so interrelated. Do you start with HTTP since that drives the web? If you do, do you first need to cover computer networking, IP addresses, routing? HTML and CSS aren't terrible to get started with, but are ultimately limited and [generally] aren't enough to build "some cool app". Then you have the beastly JavaScript, which you'll probably use on your front-end but only might use on your backend - there are so many other options. Python and Django? Ruby and Rails? Any of the dozens of PHP frameworks? Oh, right, now we might need to get into SQL. And builds and deployments and sysadmin-y tasks. Don't forget security. Or we could build everything serverless or on some PaaS, but how much understanding do you really have of what's going on there.<p>Having gone through undergrad and grad school for CS, I think part of it comes not truly realizing or accepting just how much knowledge you get from taking ~45 college courses . It's taken years for me to learn a reasonable breadth and depth of this subset of computer science, (and there's way more I don't know than I do know) and I struggle with the fact that I seem unable to boil all of that into the "a-b-a-b" pattern the author describes. Start doing the thing you want to be doing (e.g, making a web app), and learn just enough of the bits you need to keep on that path. But it's much easier said that done when you're starting from scratch.<p>It's like the pervasive interview question of "What happens when you type google.com in your browser and hit enter?"[0] Well, a lot... where do you start?<p>[0] <a href="https://github.com/alex/what-happens-when" rel="nofollow">https://github.com/alex/what-happens-when</a>