I think what I was trying to say in the beginning is that while I understand how it feels like a leap of faith, I don't think it really is. Like when I include a library, on some level I'm assuming it will really function the way the API suggests. But I don't have to take that on faith; I can read through the code, and see what it's actually doing. The code itself is an abstraction of something else, but if I take the time, I can eventually reduce it to an understanding of what's happening on a transistor level. I can't see what's happening in the CPU, but I can understand it.

I can't hold the whole model of my code at a transistor level in my head, but that's the power of abstraction. I understand what's happening on each level on some scale, I understand how the levels interface with each other, so ipso facto I do understand the system as a whole. If it doesn't behave the way I expect, I can use that knowledge figure out why, whether it's because I made the wrong call or because there's a wire disconnected on my motherboard. It's not magical; it just seems that way when I don't pay close attention.

Which is, in fairness, most of the time.