The real problem with neuroscience today isn’t with the science—though plenty of methodological challenges still remain—it’s with the expectations. The brain is an incredibly complex ensemble, with billions of neurons coming into—and out of—play at any given moment. There will eventually be neuroscientific explanations for much of what we do; but those explanations will turn out to be incredibly complicated. For now, our ability to understand how all those parts relate is quite limited, sort of like trying to understand the political dynamics of Ohio from an airplane window above Cleveland.
Gary Marcus, writing for The New Yorker, reiterates the simple fact that as much as we have studied the brain and as much as we are making progress in those studies we have no idea, still, how it works.