The best way to get a clear view of questions about truth--in the law or anywhere else--is to start, not with debates over "modernism" versus "post-modernism," and the whole dubious history of ideas they presuppose, but with a few simple distinctions.
Truth is the property of being true, what it is to be true. Of the umpteen competing philosophical theories of truth, the most plausible are, in intent or in effect, generalizations of the Aristotelian Insight that "to say of what is that it is, or of what is not that it is not, is true." (1) These theories explain truth without reference to what you or I or anyone believes, without reference to culture, paradigm, or perspective. Some of them, the various versions of the correspondence theory, turn the emphatic adverb for which we reach when we say that p is true just in case actually, really, in fact, p, into serious metaphysics, construing truth as a relation, structural or conventional, of propositions or statements to facts or reality. (2) Others, such as Tarski's semantic theory, (3) Ramsey's "redundancy" theory, (4) and the contemporary deflationist, minimalist, disquotationalist, and prosententialist theories that are their descendants, (5) don't require such an elaborate ontological apparatus.
Truths are the many and various propositions, beliefs, etc., which are true, including: particular empirical claims, scientific theories, historical propositions, mathematical theorems, logical principles, textual interpretations, statements about what a person believes or wants or intends, about social roles and rules, etc. To say that a claim is true is not to say that anyone, or everyone, believes it, but that things are as it says. However, some claims are such that the relevant things--a person's beliefs or intentions, a legal or grammatical rule--depend, in one way or another, on us; and some are such that it makes sense to ascribe a truth-value only relative to this or that community or social practice. Moreover, not every sentence, not even every declarative sentence, manages to express something true or false; some, for instance, are too indeterminate in meaning to have a truth-value.
The effect of scare quotes is to turn an expression meaning "X" into an expression meaning "so-called 'X'." So scare-quotes "troth," as distinct from truth, is what is taken to be truth; and scare-quotes "truths," as distinct from truths, are claims, propositions, or beliefs, which are taken to be truths--many of which are not really troths at all. We humans, after all, are thoroughly fallible creatures. Even with the best will in the world, finding out the truth can be hard work; and we are often willing, even eager, to take pains to avoid discovering, or to cover up, unpalatable truths.
The rhetoric of truth, moreover, can be used in nefarious ways. Hence an important source of the idea that truth is merely a rhetorical or political concept: the seductive, but crashingly invalid, argument I call the "Passes-for Fallacy." (6) What passes for truth, the argument goes, is often no such thing, but only what the powerful have managed to get accepted as such; therefore the concept of truth is nothing but ideological humbug. Stated plainly, this is not only obviously invalid, but also in obvious danger of undermining itself. If, however, you don't distinguish truth from scare-quotes "truth," or troths from scare-quotes "truths," it can seem irresistible.
Nowadays, it seems, the Passes-for Fallacy is ubiquitous. Perhaps it is rooted in the philosophies of Marx and Freud, in the idea of false consciousness and the "hermeneutics of suspicion." (7) It is enabled by regimes of propaganda and, in our times, by the overwhelming flood of information, and misinformation, which promotes first credulity and then, as people realize they have been fooled, cynicism. For when it becomes notorious that what are presented as truths are not really truths at all--that Pravda is full of lies and propaganda, that the scientific breakthrough or miracle drag prematurely trumpeted in the press was no such thing--people become increasingly distrustful of truth-claims, increasingly reluctant to speak of truth without the precaution of neutralizing quotation marks; until eventually, they lose confidence in the very idea of truth, and formerly precautionary scare-quotes cease to warn and begin to scoff: "'Truth? …