i know truth itself is not relative, so what is moral truth? to me it sounds like saying that following X persons subjective view of morality we can objectively say that Y is bad. this just then makes objectively proving a persons subjective morality a relative truth though, and not an objective truth, because we could express any side of morality, good or bad, objectively, and as you said, truth is not relative and only one truth must exist.

if you’re talking about things like Sam Harris’ definition of morality being a sort of “majority wellbeing”, i’m sure that while we can theoretically allow for the redefinition of morality and make some objective truths regaridng that subjecte moral viewpoint, but as it is not being absolute in the universe and moreso being related to subjective wellbeing of the most amount of living things, i feel that this is still just fulfilling the subjective definitions.

interestingly though, Sam Harris will go on all day about how we can’t redefine free will as being the ability to make choices which all life evidently has in common. just because these choices aren’t ultimately free, he rejects the “compatibilist” redefinition of free will.