Trust me when I say (no snark or gotcha motive) I honestly don't know what definition of truth you're using. If not some sort of ultimate or absolute truth - a concept I've tried to make clear I reject - then perhaps some kind of relativism in which we all have competing truths but no means to determine which ones work best under any possible circumstances? Do you think there is such a thing as truth under any definition? Mine may be "colloquial" but it's at least a definition. Do you reject the idea that truth can be defined at all? I've made allowances for fact as well as metaphorical truths in my responses, though admittedly I've spent no real time discussing the the latter. I'll just say here that I think to speak of a poem as "literally true or false" would, for example, demonstrate a serious misunderstanding of poetry and underappreciation of metaphor. Truth in the poetic or spiritual sense of that word, in my view, transcends fact based debates like those had in scientific or public policy contexts. But it is, as I recall I tried to make clear in my original article, precisely because fundamentalism removes the spiritual from the transcendent or metaphorical realm to the literal earthly one of science that causes it to get spiritual and/or moral truth so wrong in the end. So, in my estimation, these competing truths you speak of are really only competing when they decide to play on another truth's turf. A falsifiable question isn't in the realm of religion or literature anymore than a non-falsifiable one is answerable via science. This isn't to say we can't build bridges between the two perspectives but doing so requires humility on both sides given an acknowledgement of the limitations of each approach is necessary to make it work. So if that's your point (I have a sneaking suspicion it isn't) we're in agreement.
Regardless, I've made clear that for our purposes I'm largely referring to demonstrable facts with proximate causes as opposed to ultimate or absolute truths and first causes. This only seems problematic to me if you assume there is no such earthly or proximate truth to be had or there's some more or at least equally viable definition out there worth using to get at the fact of any given physically rooted question. If you think so, just say what it is rather than dancing around it. "All strife comes from competing truths". I honestly don't know what that means. If two or more "truths" are mutually exclusive then most and perhaps all of them aren't really truths at all. That we may think they are is beside the point, at least in so far as truth in this context corresponds to reality to at least some degree. Now if we're talking metaphor, there can be multiple viable interpretations that are "true" or at least potentially so but these waters are already muddy enough without spending much more time there.
I get that people frequently like to think they have at least more of the truth than anyone else if not all of it and this can definitely cause strife, but in most cases relevant to this discussion I clearly think there's a pretty good process available to us for settling such questions, if not immediately then eventually. Is the problem here that you disagree such a means for getting at the facts of the matter exists? Do you think there's no such thing as truth or, alternatively, that everyone's personal "truth" is just as valid as anyone else's? Perhaps you think all truth is of the metaphorical variety. Or perhaps you think facts change and truth is eternal or the other way around???