It's my understanding that nobody understands every part of major modern-day engineering projects (e.g. the space shuttle, large operating systems) completely, and the brain seems more complex than those, so this is probably right. That said, we still have high-level theories describing those, so we'll likely have high-level theories of the brain as well, allowing one to understand it in broad strokes if not in every detail.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
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