The approach in the book tries to formulate moral consistency principles that
The approach in the book tries to formulate moral consistency principles that
This isn't what it tries to do.
The approach is neutral on whether moral judgments are ultimately divine commands, irreducible objective truths, expressions of feeling, or whatever.
The approach in the book tries to formulate moral consistency principles that
This is the goal.
Just as mathematics and logic give principles that are widely shared (even though their foundation is controversial) -- so too the approach in the book tries to give moral consistency principles that can be widely shared (even though their foundation is controversial).
The approach is neutral on whether moral judgments are ultimately divine commands, irreducible objective truths, expressions of feeling, or whatever.