"On the face of it, this insistence on the social construction of knowledge may seem fairly unobjectionable and even conventional, not least for Marxists who have always recognized that no human knowledge comes to us unmediated, that all knowledge is appropriated through the medium of language and social practice. But postmodernists seem to have in mind something more extreme than this reasonable proposition. The most vivid illustration of postmodernist epistemology is their conception of scientific knowledge. Sometimes they go so far as to claim that Western science—founded on the conviction that nature is governed by certain universal, immutable, mathematical laws—is just an expression of the imperialistic and oppressive principles on which Western society is based. But short of that extreme claim, postmodernists—either deliberately or out of simple confusion and intellectual sloppiness—have a habit of conflating the forms of knowledge with its objects: it is as if they are saying not only that, for instance, the science of physics is a historical construct, which has tried over time and in different social contexts, but that the laws themselves are “socially constructed” and historically variable.
Postmodernists will often deny that they are epistemic relativists. They will insist that they know there is a “real” world out there. But the irony is that, in the very act of defending themselves, they are likely to prove the case against them and to demonstrate the very conflation (or confusion) of which I’m accusing them here—proceeding, for example, as if not only the science of physics but the physical reality represented by, say, the laws of thermodynamics is itself a historically variable social construct. They surely do not believe this to be literally true; but something like this is the practical consequence of the epistemological assumption that human knowledge is enclosed within particular languages, cultures, and interests, and that science should not and cannot aspire to apprehend or approximate some common external reality. If the standard of scientific “truth” resides not in the natural world itself but in the particular norms of specific communities, then the laws of nature might as well be nothing more than what any particular community says they are at any given time.
Not all intellectuals who think of themselves as “postmodernists” would knowingly subscribe to this kind of extreme epistemic relativism, even solipsism—though it seems an inevitable consequence of their epistemo logical assumptionsX at the very least, postmodernism implies an em phatic rejection of “totalizing” knowledge and of “universalistic” values—including Western conceptions of “rationality”... This denunciation of “essentialism” tends to cover not just truly monolithic and simplistic explanations of the world (like Stalinist varieties ot Marxism) but any kind of causal explanation...
Even in its least extreme manifestations, postmodernism insists on the impossibility of any emancipatory politics based on some kind of “totalizing” knowledge or vision. Even an anticapitalist politics is too “totalizing” or “universalist.” Capitalism as a totalizing system can hardly be said to exist at all in postmodern discourse, so that even the critique of capitalism is precluded. In fact, “politics” in any traditional sense of the word, having to do with the overarching power of classes or states and opposition to them, is effectively ruled out, giving way to the fractured struggles of “identity politics” or even the “personal as political.” Although there are more universal projects that do hold some attractions for the postmodern left, such as environmental politics, it is difficult to see how they—or, indeed, any political action—can be consistent with postmodernism’s most fundamental principles: a deep epistemological scepticism and a profound political defeatism.
How, then, does this postmodernism compare to earlier theories about end of the “modern” era? What is immediately striking is that postmodernism, which seems to combine so many features of older diagnoses of epochal decline, is remarkably unconscious of its own history. In their conviction that what they say represents a radical rupture with the past, today's postmodernist intellectuals seem sublimely oblivious to everything that has been said so many times before. Even the epistemological scepticism, the assault on universal truths and values, the questioning of self-identity, which are so much a part of the current intellectual fashions, have a history as old as philosophy...
This brings us to the most distinctive characteristic of the new postmodernists: despite their insistence on epochal differences and specificities, despite their claims to have exposed the historicity of all values and knowl edges (or precisely because of their insistence on “difference” and the fragmented nature of reality and human knowledge), they are remarkably insensitive to history. This insensitivity is revealed not least in a deafness to the reactionary echoes of their attacks on “Enlightenment” values and their fundamental irrationalism...
[C. Wright] Mills also took it for granted, in classic Enlightenment fashion, that the whole point of such historical analysis was to mark out the space of human freedom and agency, to formulate our choices and “enlarge the scope of human decisions in the making of history.” And for all his pessimism, he assumed that the limits of historical possibility were, in his time, “very broad indeed.”
This statement is in nearly every particular antithetical to current post-modernist theories, which effectively deny the very existence of structure or structural connections and the very possibility of “causal analysis.” Structures and causes have been replaced by fragments and contingencies. There is no such thing as a social system (e.g. the capitalist system) with its own systemic unity and “laws of motion.” There are only many differei kinds of power, oppression, identity, and “discourse.” Not only do we have to reject the old “grand narratives,” like Enlightenment concepts of progress, we have to give up any idea of intelligible historical process and causality, and with it, evidently, any idea of “making history.” There are no structured processes accessible to human knowledge (or, it must be supposed, to human action). There are only anarchic, disconnected, and inexplicable differences. For the first time, we have what appears to b contradiction in terms: a theory of epochal change based on a denial of history.
There is one other especially curious thing about the current postmodernism, one particularly notable paradox. On the one hand, the denial of history on which it is based is associated with a kind of political pessimism. Since there are no systems and no history susceptible to causal analysis, we cannot get to the root of the many powers that oppress us; and we certainly cannot aspire to some kind of united opposition, some kind of general human emancipation, or even a general contestation of capitalism, of the hind that socialists used to believe in. The most we can hope for is a lot of particular and separate resistances...
Even the postmodernist emphasis on language and “discourse” may be traceable to an obsession with consumer capitalism and to the conviction, already prominent in the sixties, that the old political agencies (the labor movement in particular) have been permanently “hegemonized” by capitalist consumerism. Postmodernism has simply taken to the ultimate, and often absurd, extreme the familiar attempt to replace these hegemonized agencies with new ones, by situating intellectual practice at the center of the social universe and promoting intellectuals—or, more particularly, academics-to the vanguard of historical agency.
Here too postmodernist intellectuals reveal their fundamental ahistoricism. The structural crises of capitalism since the “golden” moment of the postwar boom seem to have passed them right by, or at least to have made no significant theoretical impression. For some, this means that the opportunities for opposition to capitalism are severely limited. Others seem to be saying that, if we can't really change or even understand the system (or even think about a system at all), and if we don’t, and can’t, have a vantage point from which to criticize the system, let alone oppose it, we might as well lie back and enjoy it—or better still, go shopping...
Postmodernists reject Enlightenment universalism on the grounds that it denies the diversity of human experience, cultures, values, and identities; but this rejection of universalism on behalf of an emancipatory pluralism is contradictory and self-defeating. A healthy respect for difference and diversity, and for the plurality of struggles against various oppressions, does not oblige us to jettison all the universalistic values to which Marxism at its best has always been attached, or to abandon the idea of a universal human emancipation. On the contrary, even the mildest forms of “pluralism” have been unsustainable without appeals to certain universalistic values like the classic liberal principle of “toleration.” The radical pluralism espoused by postmodernists—based as it is on denying any fundamental commonality, or even the possibility of mutual access and understanding, among plural identities—has fatally undercut its own foundations. As Aijaz Ahmad puts it later in this volume: “if in the constitution of your identity, I have no rights of cognition, participation, criticism, then on what basis may you ask for my solidarity with you except on the basis of some piety, some voluntaristic good will that I can withdraw at any moment?” In the end, it is hard to imagine how any of the diverse struggles that supposedly constitute the left postmodernist agenda can be sustained without some appeal to those dreaded “modernist” and Enlightenment values of democracy, equality, social justice, and so on.
For that matter, it is difficult to understand how any kind of action is possible on the epistemological assumptions that postmodernists profess. Not only are their views on knowledge politically disabling, one cannot help wondering how they can conduct the normal business of everyday life without suspending their postmodernist disbelief. Either that, or postmodernist theories are guilty of more than a little bad faith...
For people on the left, and especially for a younger generation of intellectuals and students, the greatest appeal of postmodernism is its apparent openness, as against the alleged “closures” of a “totalizing” system like Marxism. But this claim to openness is largely spurious. The problem is not just that postmodernism represents an ineffectual kind of pluralism which undermined its own foundations. Nor is it simply an uncritical but harmless eclecticism. There is something more serious at stake. The "openness" of postmodernism’s fragmentary knowledges and its emphasis on "difference" are purchased at the price of much more fundamental closures. Postmodernism is, in its negative way, a ruthlessly “totalizing” system, which forecloses a vast range of critical thought and emancipatory politics— and its closures are final and decisive. Its epistemological assumptions make it unavailable to criticism, as immune to critique as the most rigid kind of dogma (how do you criticize a body of ideas that a priori rules out the very practice of “rational” argument?). And they preclude—not just by dogmatically rejecting but also by rendering impossible—a systematic un derstanding of our historical moment, a wholesale critique of capitalism, and just about any effective political action."
--- What Is the "Postmodern" Agenda? / Ellen Meiksins Wood, In defense of history : Marxism and the postmodern agenda (1997)