I am not sure where all this is supposed to lead. What is necessary is to put real people into brain scanners and expose them to various moral dilemmas and then derive mathematical models of ethical properties, statements, attitudes, and judgments from the data. If you try to figure out the meaning of terms like "altruism" or "selfishness" by contemplation you will end up introducing new and malleable definitions for those terms instead of figuring out what both, our conscious and subconscious selfs, our cultural high-level cognition and evolutionary heritage, mean by those terms. That can only be done by looking directly at the point where recursive justification hits bottom, by collecting data and turning it into mathematical precise definitions.