The term “postmodernism” (or “poststructuralism”) is notoriously elusive; it’s sometimes said that if you think you know what it is, you don’t. But that doesn’t stop its practitioners from talking about it, and I don’t think it should stop anyone else either. I will use “postmodernism” to refer to a set of ideas, widely held among academics in the past 30 years, which takes inspiration from Jacques Derrida and Michel Foucault, and denies the worth of claims to truth. One will frequently find postmodernists (John Caputo is one of the more explicit about this) claiming that “the truth is that there is no truth.”

The claim that there is no truth is false. It contains a contradiction that cannot be resolved unless one takes it to mean something very different from what it appears to mean. Nor is this one of that narrow group of paradoxes which could be taken as true on the grounds of Graham Priest’s dialetheism. Priest tries to argue that most of the problems with contradiction stem not from accepting some contradictions, but from accepting all; but if one accepts “there is no truth,” one comes much closer to allowing all contradictions in. Indeed postmodernists often approvingly quote the philosopher of science Paul Feyerabend in telling us that “anything goes.”

It is not true that there is no truth. What is crucial about this and other postmodern claims, however, is that its truth value is not the point. Like Stanley Fish, postmodernists shift our attention away from contradiction and truth entirely, claiming they’re not the important thing. (Caputo at one point approves one of his opponent’s moves because “it drops the stuff about contradiction and actually addresses the issues.”) Drawing on J.L. Austin’s theory of speech acts, postmodernists will argue that the reason to make such a claim against truth is its performative dimension. The point, that is, is not what the sentence says, but what it does.

It is on this last point, however, that the evidence against postmodernism seems strongest. What, exactly, has postmodernism accomplished? I have previously mentioned cognitive dissonance and spiritual transformation as reason to be concerned about contradictions. But these are typically not at the forefront of postmodern concern. Rather, most postmodern writers express some sort of concern for marginalized political groups – women, gays, transgendered people, the poorer or working classes, people in nonwhite racial groups, people from colonized societies. But what has postmodernism actually done to improve their situation?

Among the most widely cited exemplars of real political change on behalf of the disenfranchised are the nonviolent activists Martin Luther King, Jr. and Mohandas (Mahatma) Gandhi. Both of these men believed in an absolute truth. King’s Letter from a Birmingham Jail takes its authority from “the moral law or the Law of God”; Gandhi continually cited a Truth he identified with God as the heart of his ideals. Neither were relativists of any stripe. And it seems to me that, given their accomplishments, it could scarcely have been otherwise.

It is not merely that their faith in something bigger than themselves gave them strength as they were jailed and persecuted (though I have no doubt it did this). It is also that a strategy of nonviolent resistance relies heavily on persuasion, on appeals to justice, on making others see the case for your side. Such appeals depend on recognizing the normative force of non-contradiction. If, like Fish, you think contradiction is no big deal, then it’s far easier to ignore the appeal of a King or a Gandhi. In one sphere of your political life you preach the value and benefit of the British mission to civilize the colonies; in another, you order your soldiers to shoot colonial subjects who disobey arbitrary measures. Sure your actions contradict each other, but you don’t need to think about that. If contradiction matters, by contrast, then we must pay attention to those who note how we fail to live up to our own ideals.

Without a respect for contradiction, one can certainly achieve violent social change. One can overthrow a government by force and not be bothered by anything anyone else has to say about it. But violent social change has a harder time being a force for good. Lenin and Mao were idealists like King and Gandhi; but their names are remembered far more ambiguously, for good reason.

On this point consider the sophist Thrasymachus in Plato’s Republic. While Thrasymachus agrees that the conclusions of Socrates’s arguments make sense, he never really agrees to accept them. When Socrates presents Thrasymachus with his final conclusion – that “injustice is never more profitable than justice” – Thrasymachus does not acknowledge its truth or display a conversion, as so many of Socrates’s interlocutors do. Instead he merely seems to shrug and take an “agree to disagree” approach: “Let that be your banquet, Socrates, at the feast day today.” This argument to justice might be your opinion, Socrates, but no matter how rational it is, it will never be mine. Such a view is where the likes of Caputo lead us: I don’t care what reason says, I just keep my views.

The problem with such a conclusion, however, is expressed in the views that Thrasymachus himself is expressing. It’s not coincidence that Thrasymachus tells us justice is the interest of the stronger. For indeed, if we do not feel the normative force of non-contradiction, if we do not allow ourselves to be convinced by reason and truth, then politics must necessarily be Thrasymachean. Without an attempt to convince people rationally of the value of their positions, as Gandhi and King did, then the strong rule. But the oppressed and marginalized, those whose causes postmodernists claim to take up, are weak effectively by definition.

The rule of the strong, then, is what we might expect to see accompany postmodern thought. And is it in fact what we do see? Well, the rise of postmodernism as a theory, in the ’80s through the ’00s, coincides with the rise of right-wing politics worldwide. Social programs for the poor and dispossessed were cut everywhere; patriarchal and oppressive cultural tradition made a comeback everywhere from George W. Bush to Lee Kuan Yew; while the right wing pushed its agenda aggressively, left-leaning governments made little of the major initiatives to support marginalized groups that characterized the post-WWII era. Is all of this merely a coincidence? Causation is always hard to establish, and it would be difficult ever to say for sure. I can’t help but note again, though, that one of the first of the new wave of right-wingers, the Ayatollah Khomeini, was endorsed by Michel Foucault. That great friend of gay rights wound up endorsing a state in which homosexuality is punishable by death.

A recently popular slogan among political activists, one that Gandhi and King could easily endorse, is “speak truth to power.” Yet the whole point of Foucault’s work seems to be to tell us that there is no truth but only power – in other words, to speak power to truth. Foucault and Derrida’s views most often seem to be taken up on the grounds of challenging oppressive structures; but they are, as far as I can see, no friends to the marginalized or oppressed. Whether judged by its effects or by its truth value, postmodernism comes up lacking or worse.