The shift from current statistical modelling to sentient software is not a matter of degree, but a difference in kind. Nothing we have now is even close to being able to perceive and think in the way that a human mind does. We won't get there through incremental progress, better hardware or clever algorithms. The shift from "applied statistics" to "Commander Data" will be sudden and unexpected, as big or bigger than…
I don't think it's possible to just "think up" true AI.
I think the easiest method to achieve it, would be to first upload an actual human brain to a computer environment - by slicing a brain into molecule-thin slices, then observing the neural responses of that simulated brain.