Truth and Tolerance

I have read only a bit of Ian Markham's stuff, mostly around his epistemological argument for the Ontological Nihilism in absence of belief in God (I twist it to a 'soft' areguement merely to the Divine). In "Plurality and Christian Ethics", he addresses ethics in the Public Square, offering that;

"[T]he contemporary threats to plurality do not come from religion but from secularism. The secularist, who has given up the quest for truth and therefore moral debate and rational dialogue, is the greater danger to tolerance. A religious foundation for tolerance is grounded in the reality of God that ensures the intelligibility of the universe. This foundation is the only effective antidote to secular reason, which cannot avoid the dangers of nihilism. Truth claims depend upon the conviction that the universe is intelligible, and that in turn depends upon belief in God."

This insight, that truth is necessary for tolerance, argues that truth must be grounded ultimately on acknowledgement of God. But because people have different beliefs regarding the meaning of the term 'God", we should go further; belief in God is a belief in the Divine, but not necessarily vice versa. Belief in the reality of the Divine, not 'simply' in the reality of 'God', is considered necessary for making truths claims - valid or not (hense argument!!), and the PoMo who recourses (discourses?...), to the irrelevance of Metanarratives and offer 'ethics without foundations' or 'science without facts' or whatnot, the "Kantian" or neo Kantian who would disregard moral imperative from without, also risk discounting ontology and epistemology from without. If measures of material reality are to be founded from 'within' (as it seems Kant/PoMo people claim the reality of the moral world is 'justified'), how are they not pleadings for the axial divinity of - the speaker, of the speakers perspective? I know literary critics and English Majors tend to to write like they have Ruach HaKodesh...