Locality of concerns. I've come to realize that the fundamental issue in programming is that we all look at the universe through finite brain-sized portholes.

Locality of concerns. I've come to realize that the fundamental issue in programming is that we all look at the universe through finite brain-sized portholes. Higher order languages, structuring systems in abstraction hierarchies, and software architecture research are all attempts to organize arbitrarily large systems so that they can be understood in brain-sized chunks. One might say that well-designed large systems have a sort of fractal nature; it is possible to zoom in and out, and gain useful insight at multiple different levels.