Do we allow for a matter of degree, rather than a binary, of "zero" vs" "complete" understanding?
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.
This is a loaded question, you're assuming that abstraction and reasoning can somehow magically "turn into" sentience, whereas I posit that those two things are completely different. You can have sentience without reasoning (i.e. pure non-judgemental awareness that is the goal of Buddhist meditation), and vice-versa.