... When I talk about not knowing what you're doing, I'm arguing against "expertise", a feeling of mastery that traps you in a particular way of thinking.
But I want to be clear — I am not advocating ignorance. Instead, I'm suggesting a kind of informed skepticism, a kind of humility.
Ignorance is remaining willfully unaware of the existing base of knowledge in a field, proudly jumping in and stumbling around. This approach is fashionable in certain hacker/maker circles today, and it's poison.
Knowledge is essential. Past ideas are essential. Knowledge and ideas that have coalesced into theory is one of the most beautiful creations of the human race. Without Maxwell's equations, you can spend a lifetime fiddling with radio equipment and never invent radar. Without dynamic programming, you can code for days and not even build a sudoku solver.
It's good to learn how to do something. It's better to learn many ways of doing something. But it's best to learn all these ways as suggestions or hints. Not truth.
Learn tools, and use tools, but don't accept tools. Always distrust them; always be alert for alternative ways of thinking. This is what I mean by avoiding the conviction that you "know what you're doing".
I read all of this with a different set of associations than most people might. draw. The topic in question is programming, and there was a lot for me to glean there (what with me now involved in a few major programming projects ... more on that later). But the natural connection I made was with Zen and the doctrine of no-mind.
For those who just sat down and ordered a drink, the concept of no-mind is sometimes better explained by the euphemism "beginner's mind". One approaches life best by putting down assumptions, preconceptions, one's own situation and position, one's own self. Put all that down, take yourself out of the equation, and you'll see problems all the better for what they really are. Bonus: the more you do this, the more you find your problems are not even "your" problems, and are not even problems at all.
Stated that baldly, as the distillation of a great deal of experience, wisdom always sounds cheesy and dumb. My own experiences in this regard, I could fill a book with and probably still not convince anyone of their truth. But all I can say is, there's something vital and important there, and I wish more people were motivated to look for it in their lives instead of just distracting themselves with quick fixes.
Anyway, my point is that the attitude being described here is one worth bringing to most every aspect of life. Learn what's out there, and make use of it, but never assume it's the end of the road. That goes for your own mind as well. The things your mind tells you it wants are not always good for you, not always accurate, not always compassionate. You have to build both trust in yourself to keep moving forward, and keep enough skepticism about yourself to not step stupidly off the end of the pier. This is why Zen Buddhists sit zazen in the first place, as a way to do both of those things by teaching their minds to shut up and get out of the way.
If there's another term that comes to mind for this sort of thing, it's the cultivation of spiritual humility. Most every religion or practice path in the world asks for something in this vein, although they go about it differently. Christianity asks for it by way of spiritual identification with and emulation of Jesus Christ, Buddhism doesn't ask for the same kind of thing — rather than have our aspirational feelings ignited by emotional devotion to an embodied ideal, it asks us instead to look into ourselves fearlessly much as the Buddha did. They both ask us to follow a model of a sort, but for different reasons and to different ends. This is fine; there are as many paths as there are people, and there ought to be.
Back to the original point, spiritual humility. However you get there is likely to be worth the effort, but the important thing is not to let the tool that you use to get there become its own end. The point of loving God and Christ, as I understand it, is to also love your fellow man; without that, no amount of love of God or Christ is worth the bother. The point of studying Zen and practicing the path is to do those things, but not to get caught up in them per se. If you're peeved because your zazen is being disturbed by a cat trying to climb into your lap, the cat is clearly more important — but don't let that constitute an excuse to not do zazen, either! Be humble and self-questioning about your intentions and your actions, because that's one of the easier ways to see through them and discover what they really are.
The last point I want to make about all this, one I ought to have made first and foremost, is that "beginner's mind" is not "idiot's mind". Skepticism and a questioning attitude are made more powerful, not less, with experience. You learn all the better the traps you set for yourself, and how to not step into them — but nowhere does it say this comes automatically with time and experience. Remember my talk before about the expert beginner — better to say, perpetual amateur? That kind of naïvete is the diametric opposite of what Zen is supposed to be about.