That's why we need to decode the cognitive algorithms that generate our questions about value and morality. ... So how can the Empathic Metaethicist answer Alex's question? We don't know the details yet. For example, we don't have a completed cognitive neuroscience.

Assume you have a complete knowledge of all details of the way human brain works, and a detailed trace of the sequence of neurological events that leads people to ask moral questions. Then what?

My only guess is that you look this trace over using your current moral judgment, and decide that you expect that changing certain things in the algorithm will make the judgments of this brain better. But this is not a FAI-grade tool for defining morality (unless we have to go the uploads-driven way, in which case you just gradually and manually improve humans for a very long time).