I don't understand why you think you're asking a meaningful question. Rephrasing it: Imagine we build a robot that behaves and learns identically to a human being except it has no self-awareness. Given this robot, what is the adaptive basis for consciousness?
How is any stunning technical achievement on our part in the building of the robot related to whether consciousness provides any adaptive benefits?
PaulK's response and Modulous's addendum were pretty good answers to your question, so I'll just address this:
If we're abandoning the concept of a spirit, or a soul...
We're in a science thread. Science has never embraced the concept of a spirit or soul due to lack of evidence and so cannot abandon them. Within science the spirit or soul and all other concepts lacking evidence have no place in defining consciousness.