At what point does abstraction and reasoning turn into "sentient understanding"? How do you express that as the thing doing the abstracting? Even humans struggle at that kind of task because there's a metaphysical assumption of first principles that these models seem to be challenging (or else this thread would not have started).

Processes such as back propagation are still not understood very well in the human brain. The brain certainly uses electrical impulses in order to transfer signals, much like the 1s and 0s in your computer or phone. The gap between us and intelligent machines is probably not as well understood or clear as most people in the software industry think it is.