How/why the mind-body problem is hard

[opening paragraph]: [B]rain-imaging studies . . . demonstrate in ever more detail how specific kinds of mental activity (as reported by a mindful subject) are precisely correlated with specific patterns of brain activity (as recorded by external instruments). (Humphrey, 2000, p. 6.) Mind/Brain (M/B) correlations: We've known about them (dimly) for decades, probably centuries. And that's still all we've got with brain imaging; and that's all we'll have even when we get the correspondence fine-tuned right down to the last mental 'just noticeable difference' and its corresponding molecule.