If you believe in functionalism (~mental states are identified by what they do rather than by what they are made of), then current AI is not a dead end.
We wouldn't need to define intelligence, just make it big and efficient enough to replicate what's currently existing would be intelligence by that definition.
My point is that if you use biological cells to drive the system, which already exhibit intelligent behaviors, you don't have to worry about any of these questions. The basic unit you are using is already intelligent, so it's a given that the full system will be intelligent. And not an approximation but the real thing.
If you believe in functionalism (~mental states are identified by what they do rather than by what they are made of), then current AI is not a dead end.
We wouldn't need to define intelligence, just make it big and efficient enough to replicate what's currently existing would be intelligence by that definition.