t doesn't include useless things, like math.
That seems to be the thing that Eliezer most often mentions when he is considering what he needs to learn more of in order to further his own friendliness research!
Friendliness philosophy and FAI research are two different domains, though I was being somewhat facetious when disparaging math. It does seem as if math will end up being important for tackling increasingly meta decision theory problems, which might be most of Friendliness philosophy.
I just realized that my 'Interests' list on The Facebook made an okay ad hoc list of fields potentially related to Friendliness-like philosophy. They sorta kinda flow into each other by relatedness and are not particularly prioritized. This is my own incomplete list, though it was largely inspired by many conversations with Singularity Institute folk. Plus signs mean I'm moderately more certain that the existing field (or some rationalist re-interpretation of it) has useful insights.
Friendliness philosophy: