To arrive at the edge of the world's knowledge, seek out the most complex and sophisticated minds, put them in a room together, and have them ask each other the questions they are asking themselves.
As luck would have it, I am myself a machine that thinks, so I will share the special insight this gives me with those of you who don't share my good fortune. To dispense with vestigial metaphysical objections, we know that machines that think like humans are possible, because they have been overrunning the landscape for millenia. If we now want human-like intelligences that are made, not begotten, then it will be extraordinarily useful to achieve an understanding of the human-like intelligences that already exist—that is, we need to characterize the evolved programs that constitute the computational architecture of the brain.
Not only has evolution packed the human architecture full of immensely powerful tricks, hacks, and heuristics, but studying this architecture has made us aware of an implacable, invisible barrier that has stalled progress toward true AI: the iron law of intelligence. Previously, when we considered (say) a parent and child, it seemed self-evident that intelligence was a unitary substance that beings had more or less of, and the more intelligent being knows everything that the less intelligent knows, and more besides. This delusion led researchers to think that the royal road to amplified intelligence was to just keep adding more and more of this clearly homogeneous (but hard to pin down) intelligence stuff—more neurons, transistors, neuromorphic chips, whatever. As Stalin (perhaps) said, Quantity has a quality all its own.