You may be able to simulate all the basic mechanics of a brain and an organism by modeling all the neurons and synapses, but I suspect that the soul and the spark of sentience probably rests in quantum mechanics, string theory, multiverses, or something similar that we presently don't understand. You can build a Watson, you may be able to pass a Turing test but it wont have intuition or inspiration. Nor will it be alive or a real intelligence. It certainly might pass for an "artificial" intelligence.
Why do you think that this spark of sentience would be limited to organic, human brains? If such a thing exists, I see no reason why a silicon mind wouldn't be just as suitable a vessel for this spark.