An outline of the historical march of the skepticist-materialist argument
1) Scepticism (From 360 BC, Democritus et al) rests on the idealist epistemological assumption that we can only know an artifice of categories, which may or may not correspond to the world behind it. The world is behind a veil of categories and inaccessible. Therefore we can never know the non-artificial world. All paradigms (and their theories, approaches, etc.) rest upon a foundation; each foundation is a biased selection of these artificial categories, with no guarantees as to their veracity. Therefore no paradigms are truthful, except the paradigm that points out that paradigms are untruthful.
2) The founding Western materialist Epicurus (307 BCE) follows Democritus, but critiques the logic of the skeptic epistemology, holding that applied consistently it undermines itself and it does not correspond to how we navigate and encounter the world—how we know. (Pace Bhaskar) For realism, we must allow for actual encounters with (and feedback from) a world that can resist artificial constructions and promote innovation in categorical construction. Epicurus elaborates upon the physics foundations that emerge in our characteristic array of human senses and that emerge in but do not fully determine our concepts (constructions). The materialist system is designed to register changing (and distinguish them from consistent) relations, for a fuller discussion see Lewontin, Gould, Levins (but this has ramifications for your critique, see below). (I also have a lecture on this.)
3) Christianity teams with other Western idealists to destroy almost all materialist texts and expurge from recorded scholarship the materialist tradition for 1,000 years (from the 3rd century AD)–until the Enlightenment recovers the materialist tradition in the 17th century.
4) In the 1840s Historical Materialism (Marxism) modifies materialism’s sensory epistemology with historically-situated social constructionism—pace The German Ideology (The materialist Feuerbach introduced ahistorical social constructionism to materialist epistemology), see also Marx’s dissertation on Epicureans v. Democritus (Skeptics). Thus the epistemology of historical materialism is distinguished by three forms of recourse to the world behind social categories (which includes social and natural relations): a) categories partially informed by sensory information, b) sensory information, and c) historically-embedded relations. These three historical-materialist epistemological foundations are not held to provide knowledge completely independent from social constructions—they do not preclude social constructions, but rather they can cast into doubt, modify, limit, and check social constructions; although Marxists use social constructionism as a tool (consider the false consciousness argument), Marxism as an historical-materialist paradigm is not a radical social constructionist (idealist) epistemology. As historical materialism does not jettison ontology and its epistemology is a combination of sensory information and historicized social constructionism, its social constructionism is not absolute social constructionism.
5) In the wake of the 1967 Arab-Israeli War and the 1968 “collapse” of the French Left, Postmodernism brings the idealist skeptic project to “political intervention” by isolating (and, claiming exclusive ownership of) modern materialism’s social constructionism, while rejecting Hist-mat’s sensory epistemology and its ontology. Postmodernism claims that to know we purely depend upon social constructions, built with power-over, which can only be known as it weaves the veil of artificial constructions absolutely separating human knowledge from the social and natural world. For logical reasons adumbrated below as well as historical-political context reasons, Postmodernism’s frequent political intervention targets Marxists.
6) Thus targeted, historical materialists (Marxists) have responded to Postmodernism with the Epicurean critique of scepticism, adding the “Healthy Approach” manouever (see below). Insofar as we recognize that all categories are socially-constructed, all approaches and paradigms must rest upon assumptions, and thus scepticism can be applied to any approach or paradigm. Thus when we engage in deconstruction, critique of metanarratives, critique of grand narratives, etc., we are never innocent of politics, we always choose which foundations of which approaches and ideas we attack at which juncture. Ethically, we should be able to defend with integrity why we see the target as either the prime enemy worthy of continuous deconstruction, or as particularly prone to obscure its assumptions (eg. Because it rejects social constructionism). The Hist-mat approach holds that it clearly forwards social constructionism, that postmodernism’s social constructionism is derivative of and not epistemologically superior to Marxim’s, and Marxists clearly have explicitly, repeatedly laid out Marxist epistemology. Marxists point out that as Postmodernism fixates on Marxism as especially needing foundations-exposing political intervention above most other given paradigms, Postmodernism’s scepticism/Deconstruction/critique of metanarratives are subject to critique on the basis of what kind of social relations they support, because they can and they do choose. Although postmodernists assert the claim that the very act of deconstruction alone is definitively ethical, liberatory (as ultimately guaranteed by the skeptic epistemological assumption), nonetheless from the historical materialist epistemological position (a refutation of skepticism), each particular application of skepticism remains vulnerable to a critique of its situational ethics.
7) When postmodernists are confronted with the ancient materialist critique of skepticism (the modern version being absolute constructionism), they deploy the rhetorical move of temporarily moving down to a “soft” constructivist approach–eg. From “Lyotard’s work is characterised by a persistent opposition to universals, metanarratives, and generality. He is fiercely critical of many of the ‘universalist’ claims of the Enlightenment, and several of his works serve to undermine the fundamental principles that generate these broad claims.” down to “Lyotard’s narrative in The Postmodern Condition declares the decline of only a few defunct ‘narratives of legitimation’ and not of narrative knowledge itself. It is not logically contradictory to say that a statement about narratives is itself a narrative, just as when Lyotard states that “every utterance [in a language game] should be thought of as a ‘move’ in a game” his statement is itself a ‘move’ in a language game.” Here in its soft constructionist version, we have a postmodern admission that recognizes the defensible approach involves not fighting against the tyranny of metanarratives or grand narratives per se, but making political choices (with ethical ramifications) about which community to demand to defend its foundations. This is in essence a reversion to the historical-materialist position, which is more sustainably undergirded by historical-materialist sensory-soft constructionist epistemology, not radical constructionist skepticist epistemology in temporary suspension. If you are going to attack historical materialism on the idealist grounds of scepticism, then you must know that its critique of scepticism’s infinite logical regress is forthcoming, and you can’t in good faith defend your position from that critique by pretending that you invented or you own soft constructionism, which is a partial epistemology forwarded by historical-materialism and designed to require a materialist supplement.
Although they have been in conversation (and in the case of materialism, suspension), over 2500 years, no one has found a way to reconcile materialism to scepticism (of whatever necessarily idealist bent). They are distinct traditions, with distinct epistemologies corresponding to a presence and an absence of ontology.
Appendix: Skepticism v. Epicureanism
Skepticism (Democritus) rests on the idealist assumption that we can only know an artifice of categories, which may or may not correspond to the world behind it; we shall never know. The world is behind a veil of categories and inaccessible. Therefore we can never know the non-artificial world. All paradigms (and their theories, approaches, etc.) rest upon a necessarily biased selection of these artificial categories. Therefore no paradigms are truthful, except the paradigm that points out that paradigms are untruthful (scepticism!).
While Democritus is the skeptic that Epicureans originally critiqued, the idealist Descartes (Cogito ergo sum) is the first modern skeptic. Descartes’ skeptical hypotheses included “reality” as a dream or alternatively a contrivance of the devil. (Other modern skeptic hypotheses about reality include Brain in a Vat, Matrix, and Last Thursdayism, incl. Creationism. We will get to postmodern scepticism in a moment.)
Most philosophies have weaknesses and can be criticized, and this is a general principle of progression in philosophy. Pierre Le Morvan (2011) has distinguished between three broad philosophical approaches to skepticism. The first he calls the “Foil Approach.” According to the latter, skepticism is treated as a problem to be solved, or challenge to be met, or threat to be parried; skepticism‘s value on this view, insofar as it is deemed to have one, accrues from its role as a foil contrastively illuminating what is required for knowledge and justified belief. The second he calls the “Bypass Approach” according to which skepticism is bypassed as a central concern of epistemology. Le Morvan advocates a third, historical-materialist approach—he dubs it the “Health Approach”–that explores when skepticism is “healthy” and when it is not, or when it is virtuous and when it is vicious.
The Greek Materialist Critique of Skepticism
Epicurus started with Democritus, but had critiques of Democritus’ approach.
Materialist Epistemology is connected to Ontology
Epicurus says that all sensations give us information about the world, but that sensation itself is never in error, since sensation is a purely passive, mechanical reception of images and the like by sense-organs, and the senses themselves do not make judgments ‘that’ the world is this way or that. Instead, error enters in when we make judgments about the world based upon the information received through the senses.
Skepticism-tends-to-Nihilism (Infinite Regress)
Epicurus says that it is impossible to live as a skeptic. If a person really were to believe that he knows nothing, then he would have no reason to engage in one thought or course of action instead of another. Thus, the consistent skeptic would engage in no thought or action whatsoever, and would die.
Epicurus thinks that, in order to make judgments about the world, or even to start any inquiry whatsoever, we must already be in possession of certain basic concepts, which stand in need of no further proof or definition, on pain of entering into an infinite regress. This concern is similar to the Paradox of Inquiry explored by Plato in the Meno, that one must already know about something in order to be able to inquire about it. However, instead of postulating that our immaterial souls had acquaintance with transcendent Forms in a pre-natal existence, as idealist Plato does, Epicurus thinks that we have certain ‘preconceptions’–concepts such as ‘body,’ ‘person,’ ‘usefulness,’ and ‘truth’–which are formed in our (material) minds as the result of repeated sense-experiences of similar objects. Further ideas are formed by processes of analogy or similarity or by compounding these basic concepts. Thus, sense-experience undergirds all concepts, through which sensory data is filtered. (Historical materialists will modify this epistemology by adding a non-absolute social constructionism, but not excising the role of the senses in knowledge formation.)
Epicurus is concerned to refute the skeptical tendencies of Democritus, whose metaphysics and theory of perception were similar to Epicurus’. At least three separate anti-skeptical arguments are given by Epicureans, all basically addressing the problems with vicious scepticism, AKA either infinite regress (No idea or action can be asserted to be true, including this one, because nothing in human understanding can rest upon anything other than unprovable assumptions. A thoroughgoing commitment to scepticism precludes thought and action.) or poor-faith posture scepticism—a postured commitment to absolute scepticism (eg. A stated commitment to critiquing metanarratives.) as a fig leaf over an actual political game, the selective application of scepticism against a political enemy, whether the skeptic is calculating or being used as a tool.
For example, Harvey implicitly critiques (by analogy) a form of vicious skepticism:
“(T)he whole baggage of ideas associated with postmodernism could be deployed to radical ends, and thereby be seen as part of a fundamental drive towards a more liberatory politics, in exactly the same way that the turn to more flexible labour processes could be seen as an opening to a new era of democratic and highly decentralized labour relations and co-operative endeavours” (Harvey 1992: 353).
But though it can be portrayed that way, that is not how it is deployed nor how it operates.
Obviously, there is an alternative to vicious, bad faith, or “unhealthy” scepticism, and that is, for explicit reasons of political choice (which, Historical-materialism holds, can themselves be subject to contextual critique), deploying the sceptical approach, not as a total (totalizing) approach, but to instrumentally identify (and possibly to refine) or critique paradigmatic assumptions. Virtuous skepticism requires political judgement, and a refinement of epistemology to permit social constructionism, and not social constructionism to the epistemological occlusion of all else. (Correctly) identifying assumptions is not a complete manoeuvre, as, explicitly acknowledged or not, all approaches must rest on epistemological assumptions, even scepticism, and this includes postmodernism.
The Epicurean/Materialist Critique of Skepticism (incl. Democritus)
As Skepticism has been modified by postmodern social constructionism, the following 2/3 Epicurean critiques of scepticism pertain:
1) Skepticism is a Self-refutating Argument
If a skeptic claims that nothing can be known, then one should ask whether he knows that nothing can be known. If he says ‘yes,’ then he is contradicting himself. If he doesn’t say yes, then he isn’t making a claim, and we don’t need to listen to him.
2) The Argument from Concept formation
If the skeptic says that nothing can be known, or that we cannot know the truth, we can ask him where he gets his knowledge of concepts such as ‘knowledge’ and ‘truth.’ If the senses cannot be relied on, as the skeptic claims, then he is not entitled to use concepts such as ‘knowledge’ and ‘truth’ in formulating his thesis, since such concepts derive (at least partially-HM) from the senses.
The “Modern Epicurean” (Historical materialist) Response
Given the Epicurean tradition was destroyed for a thousand years by an idealist coalition of Christians & skeptics, materialist assumptions have been modified since the Enlightenment, notably by historical-materialism:
1) Maintenance of insistence on the role of senses in epistemology (Epistemology connects with ontology.), while allowing that social relations (featuring power) also condition the concepts (which are therefore partially social constructions) through which knowledge passes.* See E Scarry, Marxist historical materialism.
2) Maintenance of the Epicurean insistence on the necessity of establishing concepts (paradigmatic assumptions), adding a condition that those concepts should be made explicit (which is NOT understood as a property of postmodernism). The paradigm is not moot when the assumptions are exposed; the paradigm changes when both the sociological relations and the sensations informing the assumptions no longer hold.
*Note: You can see here that false consciousness is a problem for historical materialists because it is produced when power disallows and strips away sensory information from social construction. In effect, Marxists recognize in false consciousness radical social construction, and since radical social constructionism legitimates such concept-stripping (or refuse to recognize a diminishment in concept formation), Marxists do oppose radical social constructionists.
Postmodern scepticism (The aftermath of the 1967 Six-day War and conservatism’s 1969 defeat of the Paris students)
Postmodernism is modified form of scepticism that rests upon rests upon the epistemological assumption (as all positions and approaches, not just Marxism or other “totalizing ideoglogies,” must rest upon characteristic assumptions, pace Kuhn) that we can only know social constructions. This is an assumption because it is not provable against the alternative (Hist-mat) epistemological assumption, sensation interacting with social construction; but it is required to found the postmodern project (to found the view that deconstruction is a particularly, and uniformly liberatory project). It is this epistemological assumption (and the corollary jettisoning of ontology) that distinguishes the skeptic (incl. Postmodern) tradition from the materialist (incl. Historical materialist) tradition.
Postmodernism is a form of scepticism that in adopting historical materialism’s constructionism (a part of the epistemological foundation of historical-materialism, which also retains materialism’s sensory epistemology connected as it is to its ontology), was reformulated in a reaction to the materialist critique of scepticism’s tendency to solipsism (see above). Post-modernism tries to save the idealistic skeptic project by isolating and adoting historical-materialism’s social constructionism and jettisoning Hist-mat’s sensory epistemology and its ontology. Postmodernism claims that while our senses are immaterial to epistemology (sensation is always behind the veil of social constructions), we instead use social constructions, built with power-over. For social science postmoderns, rejecting historical-materialist dual epistemology and clinging to sceptical idealism, material relations do not inform concepts. The social constructions are the pure product of BrainS in a Vat. Social change is a matter of wilfully changing the concepts against a social power that exists only to the extent that we imagine it to. Historical-materialism’s weaker and sensory-supplemented version of social constructionism fails to reach the same political diagnosis.
This idealist diagnosis is what repeatedly leads postmodernists to determine that historical materialism is the most direct and dire political threat to freedom. However, historical-materialists are dissatisfied with the postmodern approach not (just) because it fingers historical-materialism as the problem but because its sceptical epistemological assumption is logically unsatisfactory and postmodernists tend to play fast and loose in alternating between absolute scepticism and soft social constructionism (just as conservative economists interpolate between hard and soft versions of their own assumptions when faced with devastating critique, pace Varoufakis, who also examines further correspondences between the contemporaneous assumptions of postmodernism and conservative economics).