It's like the "Welcome to Atheisia" thread. People wanted to deduce God's existence (or deduce that it's possible or impossible to deduce God's existence) based on universals. But to me, that achieved nothing. God also has to exist in real life, or what good is he? So I opined that any really useful belief about God has to encompass an accounting of where the rubber meets the road--how we apply the many religions and the many gods in real life.
I'm not sure that this matches the formal definition of relativism. It's partly an Fi thing, I suppose. I don't start from a starting point. I put things in context--the legal system, psychology, economic statistics, crime statistics, etc. If things aren't analyzed in the context of real life or don't immediately apply to real life, what good are they? It's a rhetorical question, of course--I realize the need to explore beyond what's immediately accessible to our five senses. But still, sooner or later things have to have application to real life, or it's just debates about angels dancing on the head of a pin, IMO.
Again, that's just my particular application of Fi. I'm not a philosopher by nature. I put things in context and set up priorities, and I accept that the priorities may have to be rearranged in a new context. Everything is relative to everything else, and nothing has intrinsic meaning; context and apposition supply the meaning.
If one must supply a firm foundation, I suppose it's life itself--experience, trial and error, application, compromises, trade-offs between competing priorities, issues of fairness, a bit of the Golden Rule, etc.
[Off to bed.]