No so much a discovery, but previous AI researchers defined what was important as what their tools were suited for. But a good counter example is speech. They

No so much a discovery, but previous AI researchers defined what was important as what their tools were suited for. But a good counter example is speech. They tried very very hard for many years, with quite limited success. As it turned out, decomposition into semantics via different layers isn't so successful. http://oxygen.csail.mit.edu/Speech.html http://oxygen.csail.mit.edu/Speech.html [Circa 2001] As for AGI, there is no supporting basis for the contention that it can only be achieved using semantic approaches, or that ML isn't a productive path.