> That world is increasingly the world we live in

I think the point of the postmodernists was that was always the world we live in, it's just that the Internet has made it much more visible and we can see the fraying and the contradictions. It's just that, for a fairly narrow window of time and societies, there was enough of an honor culture about being caught lying that the discourse-reality matched fairly well the actual reality. But even in the 20th century that required hiding a lot of perspectives, or only slowly and begrudgingly acknowledging them.

There's a distinction of degree but not of kind between "presenting the version of events most favourable to yourself" vs "presenting an entirely fictional version". I don't know how we get that back.

A lot of what enables this is centralized infrastructure. If you have your messages and browsing history and files on your own device, and you make end-to-end encrypted connections to the people you talk to, it's a lot harder to do this kind of thing. Because you have your own personal copy of the thing from when it first happened and if you remember it you can go back and verify it yourself. Then you can point that out, and anyone else can go into their own copy from however long ago and see that the fake doesn't match the original.

Social media companies notoriously blocked users from sending a story to each other in DMs a couple of years ago. It's not a stretch to go from there to deleting past messages in order to memory hole something. And the companies may not even be doing it by choice if they're being pressured by a government.

They can't do that if your data is yours and they can't read it, instead of the only copy being on their servers.

Disconnect and build a network of trust.

There is nothing in principle which prevents us from solving this problem. We cannot predict which new knowledge will solve it. But we can say that if we don’t solve it, it will be our fault for not producing the required knowledge fast enough.

> Now they look more like prophets.

Not to me. They just look like another group claiming grand and sweeping theories of truth.

So I mean, postmodernism is a pretty "diverse" field, and while there are some who would claim to be full relativists, they aren't usually taken very seriously.

What someone like Herbert Marcuse would claim is that there is something like a "definite negation," or Jacques Derrida would call a "trace;" that is, there, sitting behind every signifier (of de Saussure's structural linguistics) its negation of another signifier that defines its position in an ordered chain or a symbolic network. They would not argue that things are relative; rather, social life is regulated by these vast signifying networks that one becomes "subjectivated" in (begins to understand oneself as a subject), where one's "agency" also stands at the limits of this intelligibility: as they say, everything you "decide" is already pre-conscious; every notion of what is "possible," is limited by what is already "intelligible," i.e. what operates in the social-symbolic function as it, like an algorithm, constantly moves and exchanges its various symbolic orderings in what we call the "economy." To be a true agent means to do something which radically restructures this network and radically redefines all its terms: Foucault's "fearless speech," Badiou's "Event." The latter thinker actually explicitly rejects relativism (and is in some ways a platonist--actually many so-called "postmodern" thinkers, Whitehead among them, are considered platonists.)

The position you claim is from "post-modernism":

>"claims of truth are just assertions of power"

finds its origins in Nietzsche, who famously claimed that truth, morality, beauty, etc. were invented by the weak because they feared the powerful and they were jealous of the fact that they couldn't kill their enemies, eat fully, and have sex all the time (Master Morality, which was just doing whatever you wanted). So they rose up, took over, and invented these categories and systems of valuation in order to justify a new regime of power where nobody was able to do what they wanted, and everything was regulated by vast systems of control justified by these metaphysical notions (he refers to this as "Christian Morality.") He claims that Christian morality, after centuries of struggle, has finally won out in the Bourgeois revolutions of the 18th and 19th centuries, but now "God" has been subordinated to "Science" while retaining all the metaphysical baggage of christianity "truth, beauty, morality," etc. This is from Nietzsche's Genealogy of Morals, the argument from which was expanded in Foucault's Discipline and Punishment (the most widely read book from what most people would call "postmodernism").

>truth that is actually true, true in the old sense of corresponding to the reality of what is

The so-called "correspondence theory of truth" is considered a fallacy of the layman in academic philosophy. Truth has always been, in logic, a category: a value, specifically a boolean value. One can make claims about the structure and order of logic and the relation of that to psychological, social-processes (as Frege, Husserl, and many other "anti-psychologists" of the 19th and 20th centuries did); but to claim that language, a signifying act, somehow directly corresponds to the physical objects that it categorizes, can't really be valid: as Shakespeare said "a rose, by any other name, would smell as sweet." There is no reason why the words we use have any correspondence to experience--even if there is surely some reason why words can evoke experiences, emotions, like when one hears the name of a past-lover. But that can be attributed to what the "postmodernists" claim: the name evokes an entire symbolic structure and brings it to the surface of consciousness.

You can make a distinction between empirical truths and things (often claims) that are right and wrong. The former has no 'history'; while the latter is contextual and tied up in the practice and expression of reasons, which is to say, it is essentially historical and cultural.

That's really all that postmodern thought says really. Naturally, for a government to be right or wrong, requires that citizens be critical of it, almost actively antagonistic in their demands for reasons, evidence (be it empirical or otherwise) and clarification. Postmodern thought is a critical tool. So that's not that different than what we have right now (most of HN for instance is hyper-critical of nearly all government truth claims), only the demands on citizens are likely outpacing their resources and abilities.

I don't have any prescriptions for society as a whole but I can tell you what has worked for me.

Basically I rely on my own observations and experiences: don't trust and verify, to adapt the old saying.

Second I limit myself to trusted sources of information and if I can't find one then I just don't get information on that topic: no information is better than false information.

In practice what this means is no algorithmic news feeds, I'm still looking for a good news source for my local city (haven't found one yet, I moved recently), I think a lot about incentive structures and how that might bias an information source, I (try) to apply skepticism to what I read, I block as much noise as possible (for example I don't pay attention to surface level political news because its all noise and virtually no signal), I focus on long term trends rather than "points" in the timeline.

This is far from perfect but its what has evolved as my approach over time.

They have always been crooks. Just because lying has become even easier doesn't mean that there is no truth.

>The question becomes, how can we stay sane in that world?

Diversify your information sources.