To me, relativism seems to take away the justification for judging one claim superior to another claim. In the absence of being able to make such judgments, how can knowledge advance?
I think what your looking for is a sort of 'undeniable truth' that is repeatable, easily understood and shared. But the problem is finding what that 'truth' is and convincing people of it.
I think is even worse then that Proscrutes , I think ultimately, Relativism undoes itself...if we are to "relativise" relativism to exclude any form of absoluteness, relativism falls apart on its very own premiss...and I think this is not just a fortuitous rhetorical display for the sake of arguing problem being raised here, this is a genuine observation regarding the ultimate consequences on the rational consistency of a relativistic approach to the experience of reality...
On that regard, is then, it seams necessary, to continually make a clear distinction between the undeniable existence of a Truth or a True state of what we call Reality and the possibility of perfectly knowing, almost like "repeating" such Reality for what it is onto itself...Reality as a whole is not repeatable if One !...thus and therefore to my view, to avoid the usual chain of mess and confusion, the need and the relevance of qualifying knowledge on its proper rightful ground... "knowing" is not an adjective who can qualify to "mimic" reality as a whole in a chain of causes and explanations but rather refers to an objective particular form of relation regarding the seeking of a particular conscious being, or a particular Civilization, who is absolutely phenomenally valid, even if subjective on what it can account for, reason about, or what it refers to, once finite in extension and meaning, which again is itself an objective part of reality, or Truth itself, Truth which is itself the very root of all subjective and relative experience as an objective noumena on its unshaken unquestionable necessary wholeness...thus Knowledge is/must be, an objective part of the process we use to call "reality" which as a set, accounts for a partial explanation, a summary or a resume upon those aspects or property´s of relations between "entity's of experience" or phenomena, which at some point in history can be meaningful to us... but of course sounds reasonable to conclude, that knowledge cant ever account for reality itself as whole if an inclusive part of such reality which itself is not resumed to the existence of knowledge...