It has occurred to me that something theologians (of my sort) and philosopher-scientists (typically of the athiest/materialist sort) have in common is that we are philosophical realists. What we both take to be true, is (1) there is a material world having a structure and history (facticity) with positive qualities preceding and having nothing to do with human consciousness, and (2) that in or with mind, we can come to know, that is accurately represent to ourselves, the structure and history of that independent world. This is not to say that we represent it perfectly or even at all when it comes to some of its more extreme phenomena. The bottom line for realists is that as concerns the bric-a-brac of day-to-day experience, what we see (experience though mediating senses) is pretty much what there is that is independent of our mental representations.
I’ve recently read two books (“Living in the End Times”  and “Less than Nothing: Hegel and the Shadow of Dialectical Materialism” ) by Slavoj Zizek, and two from Arthur Schopenhauer (“The Fourfold Root of the Principle of Sufficient Reason”  and the first two books of “The World as Will and Representation” ). It’s been 40 years since I’ve read any Hegel, Neitzsche, Heidegger, Husserl, Wittgenstein, or Marx. I haven’t explored any modern antirealists like Quentin Meillassoux (an antirealist seeking a justification for realism, next on my “to read” list) at any time. The antirealist viewpoint, not the examination of the structure and nature of consciousness (their only program), but the ad hoc rejection of that structure being representative of a world radically independent of and prior to consciousness, is alien to me.
Having stumbled onto this point of view in recent reading, represented to me mostly by Zizek (who is an acknowledged heavyweight in this domain) this essay compares some consequences of the fundamental ontological stance of Realism and Antirealism. This is not an exhaustive review of either side (see the SEP entry on Antirealism here for a great introduction). My goal is to highlight what I take to be the fundamental antirealist problem and argue that it is a much bigger problem than the fundamental realist one.
Modern realists, the “New Realists” like Maurizio Ferraris, understand that “what we experience” are “mental representations”. What exactly constitutes “the mental” (consciousness) is hotly debated among realists, a debate I won’t get into here (see “PHYSICS AND THE EVIDENCE FOR NON-MATERIAL CONSCIOUSNESS”). But there isn’t much debate about the subjective perspective (and language) from which we are all forced to communicate both what we experience and our ideas about that seeming, including its correspondence with the external (connected up to its truth; see “TRUTH AND TRUTHMAKING”). All of these are ingredients of “the subjective” within which the external world (including the bodies containing the sensory organs on which that world impinges) is somehow or in some sense modeled. The realist’s realism consists precisely in taking this modeling to be accurate, properly representational of “what is out there” at suitable scales or graining.
This last part, the graining, is important. Modern realists believe there is “independent reality” at scales both too large and too small for human senses to probe directly; roughly anything smaller than a dust mote or larger than a mountain. Below and above these sizes, instruments enhance our senses allowing us to probe the very small and very large. We build the instruments at familiar scales, but they work to map the larger or smaller onto scales which we can sense directly. The broad assumption of realism is the map, our mental modeling emerging from instruments through our senses, is accurate. This means not only that the content of consciousness represents a real-external, but also that the structure of subjective content reflects the structure of the external.
We extend what we know (internal experience) to phenomena outside our minds by trusting the map. Modern realists even approach antirealism in recognizing that there are phenomena whose positive properties will always remain unknowable because they cannot, even in principle, be probed by macroscopic instruments. This is the quantum-real on the smallest scales and the cosmos beyond our visible horizon at the largest. But while there is no “trustable map” potentially available here, realists do not doubt there is something real and independent of mind at these extreme scales. Further they have a faith in our eventual ability to explain the emergence of the bric-a-brac world from those unknowable phenomena. Achieving this would be tacit evidence that our theoretical speculations concerning the unknowable reflects more rather than less of structure beyond the range of our instruments.
A few scientists and philosophers argue there is no independent real except for the extremely small (or even the Wave Function) which cannot be known. This “scientific antirealism” is not the same [metaphysical] antirealism I address here. Even these antirealist scientists admit that anything we elect to “call real” (for practical purposes) in the intermediate scales, is “faithfully modeled” in the mental experience of the scientist. To most realist scientists, the mental ability to conceptualize different scales itself also represents the structure of reality independent of the mind doing the conceptualizing. Unaided by instruments, phenomena on scales to which we are sensitive are real. What eyes see, ears hear, noses smell, and our bodies physically feel in their encounter with the world is all real and ordered (structured) as we perceive them even as we have also learned that at different scales reality’s structure lies beyond what senses can detect and even (possibly) what mind can conceptualize.
So what exactly is the problem with realism? Pre-philosophically realism seems, well, obvious. Early modern scientists were religious men. They grasped that God, if real, had to be consistent; changeless. They reasoned the regularities observed in the universe were a reflection of God’s constancy. That assumption grounded the idea that the “laws of nature”, the physical laws of God, were discoverable and mathematically qualifiable.
Later, early empiricist philosophers (Locke, Hume) dared to suggest that the regularities of nature were the constituents of “material stuff”. The closure of physics on itself is taken to be a sign that the properties of the physical come from nothing other than the physical; self-generating brute fact. God’s constancy, even his presence, becomes redundant. Being could be self-sustaining! Antirealism began as an attempt to save God, more precisely the doctrines of the Church about man. There is some irony in that today’s antirealism is even more radically atheistic than most realism. Materialist-realists mostly admit that God, as a source, an origin, is not incompatible with physics, merely redundant. Antirealists, by contrast have come to assert that God is impossible.
Realism today, among scientists, has little connection with theology. But on becoming atheist, realism faced a philosophical problem. What guarantees the veracity of the map, the connection between our singular individual internal experience and the external world? We know the brain is a warm, wet, electrochemical environment, obviously a material object constrained to regular behavior consistent with natural law. Most scientists suppose not only that this brain, by itself, is sufficient to produce consciousness, but that this subjectivity properly models the world as our senses relate it to us. How exactly does that work? Without God, in this case a bridge between the internal and the external, what justifies the internal conviction that experience reflects reality?
We know that brains fail and that in failing they can produce all sorts of deceptive maps. The problem, called the “representation problem” is explaining how it is they produce truthful models most of the time? Truth, means there is some one-to-one correspondence between something in the world and its representation in subjective experience such that we (at least humans) can claim knowledge of the external world as represented in internal experience. If one has God of course the explanation is available. God (via some mechanism he uses to add mind to brains) sets the world up that way. Mind evoked on brains, functions, by design, to represent the external-real to the subjective; to produce veracious maps. This explanation tells us nothing about the mechanism of the relating. It removes not the mystery of the mechanism, but only the mystery of the facticity of its result. If God is real, then we would expect that mind (however produced) models the world because the same self-consistent God produced that world; the purpose (among them) of mind is to model the world to the subjective viewpoint. The mystery of how mind does this remains, but that it happens is not a mystery given theism.
So what arguments do realists who are not theists advance to explain or justify the veracity of the map? Mostly the problem doesn’t trouble them because the origin and nature of consciousness itself presents a bigger and encompassing problem. Realist-materialists mostly assume that, when we get a genuine reductive explanation for consciousness, the representation problem will take care of itself. We will know why consciousness produces an accurate modeling because (1) modeling is intrinsic to consciousness, and (2) we will know how it is that consciousness comes about. Notice that (1) has the same structure as the argument that God is redundant because the material world and its regularities are self-constituted; material being is a brute fact.
Materialists point to our survival as a species, and the progressive evolution of consciousness not only as evidence the map is accurate, but also is the reason for it. Suppose as consciousness evolved from the lower animals there were cases of both true and false (corresponding and non-corresponding) modeling not just as concerns individual sensory events but in the consciousness of the creature over-all. Those creatures having inaccurate maps are more likely to die early (perhaps because they fail to avoid some predator) and not reproduce. Those whose maps are more accurate, more corresponding, survive to reproduce. This doesn’t explain how it is that any accuracy is achieved in the first place. It doesn’t explain how a connection between the model and the world is possible, but it is a plausible account of the Darwinian ground of its achievement. Realists (without God) have not reduced the representation problem to physics, but this failure does not mean realism is wrong.
Modern antirealism began with Kant, with his idea that the right way to do philosophy is to begin from within the subject. Antirealists and realists alike admit that, after all, all experience occurs within a “subjective arena”. Moreover, they agree that this subjective is a phenomenon “in the world”, that is in the broader context we might loosely conceive as the “totality of the universe”. That last notion, that there is, conceptually some total, that the idea is coherent, comes mostly from the realist side.
Antirealists today will mostly claim that not only can we not directly experience such a total (most realists agree) but conceptualizing a totality is meaningless (perhaps incoherent like a square circle), amounting to “begging the realist question”. There is some irony here in that most antirealists today are also materialists. They have to say that the subjective arena is simply “another component in the world” while remaining metaphysically non-committal about the nature and even existence of “a world”. Realism is first a metaphysics having epistemological consequences. Antirealists mostly abandon metaphysics (being unknowable) and fold what is left of it into epistemology. Since we cannot have knowledge of an outside, we cannot know if there is a total, an all of it.
The first historical result of that irony for antirealism was radical idealism. In the 18th century George Berkeley, “Bishop Berkeley” of Cloyne, took the antirealist idea and ran with it. Being a theist Berkeley was free to make an extreme claim; there is no “external world” at all. Not only must all experience be inherently subjective, but that was all there was to being in his ontology. The subjective is all there is and anything that seems as though it is external to the subject is put there, that is into the subjective, by God. God makes multiple simultaneous subjective experiences consistent. If I see a tree and you, standing next to me, also see the tree, it is because God put the tree into both our minds in just the way that it appears to us individually.
Obviously materialists cannot take this seriously, and even theists no longer give it much thought. The latter might acknowledge that it remains a theoretical possibility, but it seems far too improvized, even compared to the theistic solution to the reference problem. In today’s terms, radical idealism collapses into a variation of the computer simulation hypothesis in which God plays the role of the computer. This, in turn, collapses into solipsism. Perhaps everything I take to be another is only placed there for me.
By dropping God, antirealists face a philosophical problem far greater than the realist’s inability to explain representation; they find themselves with a well neigh infinite set of possibilities with no intersubjective mechanism to separate the sublime from the ridiculous. There might, hypothetically, be an infinite number of realist theories explaining our experience. But those theories, to be counted at all, must not only account for what appear to be external constraints, the behavior of the seemingly external universe, but also assume its metaphysical primacy.
By contrast, antirealist theories are constrained only by what is possible subjectively and this includes not only what appears to be external, but also such internal experiences as imagination, fantasy, fiction, and psychosis! Further, all the set of antirealist possibilities can be applied to anything. Not only might such analysis be fruitful in subjective-centered disciplines like art or psychotherapy, but also in inter-subjective phenomena like history, economics, and politics as these too exist to-the-subject only in the form of what makes itself known across the boundary of the subjective.
Antirealists since Berkeley claim there is an objective world independent of the subject and the subject (and subjectivity) is a part of this world. They also claim however that we cannot know in what this objectivity consists. All we can know is what it is experienced like from the inside, the subjective. Not only does this idea that “experience alone is knowable” apply to the external world (whatever it might be) but to the subject itself. We cannot strictly know our own subjectivity in any complete way either. Specifically, our experience, being what it is, we cannot get behind experience to find the subject of experience. In modern antirealist writing this comes out to everything, the seeming-world and the seeming subject of experience, emerging only from boundaries or horizons (the fact and content of consciousness) beyond which lies we know not what!
This (in a painful inverse of radical idealism) leads antirealists to suggest the possibility that behind the boundary there is nothing at all, that even the boundary is nothing and that behind it is less than nothing! Truth is like a rainbow, a phenomenon that has no ontological presence but rather emerges in consciousness from that which we do not see directly; in realist terms water molecules diffracting light. Not that antirealists can claim “there is nothing there” because after all they cannot know this, but what they can know (they suppose) is that “nothing at all” is a possibility, and if not nothing, then undifferentiated chaos, a universe of meaningless multiplicity about which we can say nothing. Structure comes only when the chaotic crosses the horizon of experience.
Homologous to the realist assumption that physics is self-constituting, consciousness, “whatever it is” is also self-constituting (tensions or torsions in, or exceptions to, the “unknowable multiplicity of (non-totalizable) universality (Zizek)). In another ironic twist having no homologue in realist circles, one of the possibilities for the explanation of experience in antirealism is realism (see Quentin Meillossoux “After Finitude” )! To be sure antirealists cannot assert that realism is true, but they must accept that it is a possibility! Today’s Postmodernism is a direct consequence of these antirealist contortions. If truth can emerge from anything, even nothing, if truth’s foundation is entirely subjective, then perhaps there is no truth to be had at all, no ground for morality and so on.
But Postmodernism goes too far. Zizek points out that reality can be so chaotic (the universe at all levels of graining taken at the same time) or horrible (the holocaust) that subjective mind is overwhelmed by everything and cannot grasp anything. “Fiction has the structure of truth” (Almost the opening line of Zizek’s “Less than Nothing”) means that by fictionalizing “the real”, meaningful patterns invisible in the swarm of facts stand out. We experience their presence. This can happen also with “mistaken interpretations” of philosophical arguments or viewpoints, and also with art. These can unexpectedly reveal otherwise hidden insights or issues in what was intended by the author or artist.
Zizek is quite correct in that the “truths” revealed in this way arise purely in mind, but realists recognize that truth as such is a mental object, a part of the content of consciousness. The issue is whether or not what is experienced in the subjective, the pattern, “the truth” is represented by something identifiable in the external-real event to which it corresponds; of which it is a recognition, not an invention.
But what then is the antirealist response to this inverse of the representation problem? If realists cannot explain how it happens that our mental models are representative, how do antirealists explain, since we cannot know that our models are representative, why it is that airplanes fly? Realists point to such artifactual objects as airplanes (classical physics), and modern computers (quantum mechanics) as evidence sine qua non of the correspondence between model and independent reality. How, if we do not know in mind something of the structure of reality outside mind, do we explain our technology?
Antirealists here rely on what, in my opinion, is a pseudo distinction, one that only applies in mind, but cannot apply to a mind independent world, a distinction that amounts to “begging the antirealist question”; that between “working for-us” and “corresponding”. Our technology seems to work because it does successfully manipulate the horizon (qualia and such) that confines our subjectivity. To antirealists technological prowess does not mean that we know what is going on beyond the boundary only that what we experience is in line with our purposes (our intent for the technology) from our viewpoint on the inside.
Antirealism is to philosophy a little like String Theory is to physics. String theory has not brought relativity and quantum mechanics together despite 30+ years of trying. But it has resulted in many useful mathematical discoveries. By abstaining from talk of the external world (whose existence they nevertheless grant) antirealists have discovered much about the internal one.
Realist-materialists often have a difficult time with the idea that there are fundamental limits to what we can know, limits to mind’s ability fully to interpret material reality or mind itself. On the physical side, quantum mechanics is the quintessential example these days. Here it seems reasonable to believe that we can narrow the domain of that which we cannot interpret. But as concerns mind, there must be positive fundamental limits. Why? The antirealists understand this better than the realists. Mind is something in the world, but it is precisely that in the world in which we, the experiencing subject, are locked. We are inside a box. The box interacts with what is outside the box with sensory apparatus, but inside the box we experience qualia, an interpretive effect of sensory operation. We know the qualia conveyed to us, and in addition our purposes, emotions and so on, but not directly what lies beyond the boundary nor what exactly, on the inside, is having the experience.
Qualia are a boundary. Qualia are not the thing-in-itself outside the box. But they are what (to a realist) permit interpretation, knowledge, of that which lies outside the box while to an antirealist they are the only phenomena which we can know. For both realists and antirealists it is this interpretave experience that distinguishes the inside from the outside, but neither realist nor antirealist has any direct access to the “I” which experiences.
The I has nothing analogous to qualia by which it can interpret itself, that is distinguish itself from the content of consciousness. The “us”, our “I” is a horizon of the inside, the slippery object which we are fundamentally unable to analyze. To be consistent we have to say that, as with the “external world”, we cannot know anything about the “I”. Like the external world, the “I” might even be nothing at all. To all intents and purposes it might as well be nothing because, as with our senses, we experience not the thing-in-itself but only its boundary, the place where its illusion emerges into subjectivity.
Realist-materialists make the same invalid deduction with respect to the person that they do concerning the independent world. “There is nothing other than physics (the material world) because we can (a) explain all of physics and (b) not find anything other than physics with physics!” When we “look for” our center, our “I”, we do not find it. Since, from a realist viewpoint, we should find anything there is on the inside, there is therefore nothing there, no I. Antirealist-materialists are more sanguine about the external world because they “cannot say anything positive (meaning assign it positive, knowable properties) about it”. But with regard to personality, which if it is a positive reality must nevertheless be non-material, they make the same mistake as realists. Because we cannot find it (the person) there must be nothing there.
Realist-materialists might be mistaken about the completeness of physics, but at least their philosophical contortions stop there. Antirealists are not so lucky. Mind is an illusion (not material), and the person, the interior “I”, is also an illusion, a “hallucination halucinating a hallucination”. Zizek quotes this approvingly from Metzinger but goes on to say that Metzinger makes a mistake by not recognizing that a hallucination redoubled sublates itself, and from that dialectical process a reality (something positive — consciousness and self?) emerges.
From a realist perspective this is absurd. Zero “0” is a placeholder in mathematics. As a sign in the world it stands for nothing. Nothing plus nothing (0+0) or nothing times anything, even infinity, is precisely nothing. Everything that is real in the universe is either positive (atoms, chairs, “the universe”) or emerges from something positive: the rainbow from water vapor plus light, cold from a relative absence of [molecular motion] heat, and even evil from an intentional choice to commit error; an act positive not in the sense of “being good” but in the sense of being “a physical cause”. We need negative numbers for the consistency of mathematics, but they aren’t real. They don’t represent anything “in the universe”. If I add a negative three apples to a positive one apple (-3+1) I do not have negative two apples, I have precisely zero real apples.
In the human case, minds are directed by something intrinsically central to subjectivity. No we cannot find that center when we examine our own minds, but that we can examine (even partially) our own mind proves that the person is real, positive. Something exists that [partly] stands outside mind. The antirealist insight that there is subjective experience we cannot encompass because we do not and cannot stand “outside it” is genuine, but it does not mean that what we cannot reach is therefore nothing.
Purposeful intention is both real and positive. All of what is real, material and non-material alike, must have positive properties even if we cannot always say what, exactly, they are. Only in antirealism does something apparently come from nothing. The quantum vacuum (cited as counterexample by realists and antirealists alike) is not a metaphysical nothing. To realists, minds, be they the minds of lions chasing zebras or humans building airplanes, make a difference in the world, they cannot be nothing.
Mind is only the first step. Self-consciousness is possible only if something positive exists, at least partially differentiated from mind itself; within the box yet distinct from its purely mental content. Something positive is differentiated from the content of consciousness yet remains entirely dependent on the subjective arena for its expression. It is responsible for the recognition by that subjectivity that there is something both within and apart in it simultaneously. But the person is the end of the line. We cannot find personality directly because nothing stands outside it.
Personality transcends mind, views it as it were from an outside. But its difference or distinctness is not complete; partial. Partial is important because whatever personality is it experiences and expresses itself through mind. It is a pattern of some sort made of mind. This is why we cannot find a clean joint between mind and personality, but only a fuzzy one. Mind and the “I” together seamlessly constitute subjective experience! See my WHY PERSONALITY for a more detailed discussion of this.
Materialists of either realist or antirealist persuation both assert that free will is an illusion. The incoherence of this view is demonstrated by the impossibility of asserting its truth if it were true. Such assertion, given the subjective appearance of freedom must devolve into a Postmodernist rejection of all truth. If there is no free will then “there is no truth” that we can assert, because we are trapped in the role of “mouthpiece of the universe” having no idea whether what we [determinately] say is true or not. We might say that “it seems true to me”, but the me is an illusion, a hallucination, and after all we were deterministically impelled to say that too (see WHY FREE WILL and ARGUING WITH AUTOMATONS for more discussion).
If the Respresentation Problem is realism’s biggest challenge, antirealism’s seems much bigger. In theory the representation problem has a solution, but there is no end to the recursive possibilities possible in antirealism. Given the latter’s conviction that truth is only about the inside, within the arena of experience, the possibility of uncheckable recursion is fatal to the antirealist program. Realist-materialists might mistakenly reason there is no God, but the honest ones know that God remains a logical possibility. By contrast antirealist materialists (at least this is my interpretation of them) are ultimately forced to the conclusion that God, a real God independent of human experience not only does not exist, but cannot possibly exist.
In Realism universals (Realism does not deny universals) have particular instances. “Color” has Red, Blue, Green, and so on while particular modes (the redness of a particular apple) instantiate in particulars (the apple that has that shade of red — I follow here E.J. Lowe’s “Four Category Ontology” for example because Lowe was a Realist-materialist). In Antirealism universals can’t have individual instances. Particulars can exemplify universals for realists but there are no particularized universals in antirealism except the subject who is universal, whose experience is the only universal, for herself.
This “logic of the inside” reaches its apex for the subject, and subjectivity, itself. From every individual’s viewpoint, their own subjectivity, my universal for-myself is at the same time the ultimate particular. There is only one of that viewpoint in all the universe. There cannot, therefore, be an external “universal subject”, “a God”. A real, positively existing, God would occupy all separate individuality simultaneously. If God is “the universal person” then individual persons, that is an individual point-of-view, multiple in the universe yet universal for itself, would be impossible.
The person and her experience faces the outside which is nothing. She cannot find herself on the inside either, another nothing. From the gaps (horizons) between the nothings emerges our particular viewpoint which is also nothing and so comes from “Less Than Nothing” (the title of a Zizek book). Everything, because our experience after all makes up the all-there-is for each of us, is subject to this endless recursive descent of meaning. There is no stable social relationship because the outside is incomplete and the inside never fully known. Any evolving socio-political world, any particular example of it, has to crash against what cannot be known even on the inside and must inevitably conflict it.
Hegelian antirealists (my interpretation of Zizek) view history as an endless repetition, doubling down, sublation, and re-emerging with what was always there. History’s expression only seems new but is really nothing but a shift in perspective by the subject, herself emerging from the internal void as history emerges from voids both internal and external. Art of all kinds is subject to endless reinterpretation not merely (and sensibly) in historical context but intrinsically. There is no end to what art “can mean”. Nothing is necessary (everything contingent) yet the unfolding (and remember we are in consciousness) follows its own inexorable logic. The unqualified “real world” is unstructured, chaotic, actual-in-itself, potential-for-us. It is only the inside that structures it.
Capitalism is unique in the history of economic systems not because it is different and happens to be dominant in the present, but because it is the first of the economic systems whose “seed of destruction” lies not in its relation to an external environment but is built-in to it. Capitalism must grow forever (obviously unsustainable) and yet will not work at all without this excess at its core. The inconsistency in capitalism isn’t merely between it and its non-economic (political, social, ecological) environment (although it is that too) but is a fundamental part of how it works. Without that part of itself, its demand for endless growth and capital (self) accumulation it wouldn’t work at all. Remember though that all of this process takes place in and to experience, subjectively. In this realm, capital itself “comes alive” as it were and becomes “self serving”. Mind that produced it cannot fix the destructive ambiguities at its core.
There does seem to be something insightful in this, but only if its life is represented also in an intersubjective independent world. It is not capital’s “life within the mind” that makes it hard to correct imbalances or mitigate evil (gaming the system) but the fact (however it came about) that this subjective construct is mapped into independent-world effects that correspond to what we experience of them, often times economic disasters that bring misery to billions. All this is true of history more generally speaking. But it is a mistake to move from this insight to the assumption that the ambiguities and inconsistencies, both negatives in the sense that no ontological object exists for them, no positive qualities, are the core itself; that there is “nothing more” to the core than this negativity. Applied to history this comes out to there being only contingency; no such a thing as progress. Antirealist “intuitive logic” forces them to these conclusions, but they don’t seem so obviously true to most realists.
To be sure notions like progress in a moral sense are often rejected by realists as well and for the same reasons. Only as concerns the representations of physics do realists believe there is a, more or less, “immutable standard”; intersubjective agreement on theoretical implications coupled with experimental agreement.
Not surprisingly, sex gets some of the most convoluted analysis. Not the sex-act (though that too gets its share) but sexuality in general. Not-man is woman, but not-woman is an impossible universal and so not man. There are not two sexes but “one and a little more”, and so on. One is reminded of Freud’s quip (which Zizek quotes) “Sometimes a cigar is just a cigar”. The antirealist mistake is a failure to recognize that most of the time a cigar is just a cigar. In stereotypical Freudian fashion, sex gets tied into everything from itself, the sweep of history (it is not enough to note that there would be no human history without it), the entire edifice of art, and the very ontological foundation of being!
Language is the intersubjective expressive instrument of all that goes on in experience. Language is finite and imperfectly expressive. Fiction can reveal truth but also obscure it. In their examination of language (something after all we all experience subjectively), antirealists have subjected it to more recursive convolutions than sex. Even the materialism of antirealist-materialism emerges, in experience, from the inability of lauguage to encompass the “out there” void itself merely a reflection (sublation) of the “in here” void. Chairs, or stars, exist, for example, because we can name (signify) them and what we cannot name can only be chaotic void. Mind is not recognizing patterns emerging onto its horizon, but generating those patterns which are otherwise “only void”. To be sure not all antirealist philosophers go all the way down with this recursive process, but the problem is there is no natural stopping point, no standard against which its theories can be compared. Nothing can be rejected. Any hypothesis we imagine is possible.
Realist physics has its own problems with indefinite speculation because, after all, the representation of the senses, even enhanced by instruments, doesn’t go “all the way down”. The string theory M-Brane universe of 11 dimentions is a fitting example. But there is a check on realism, at least in its dealings with the external. Speculation has to make predictions that are, at least in principle, testable. If it does not, it is never taken quite seriously. Antirealists can always say “the turning stops here”, but the next philosopher comes along and says “no there is one more turn” and this “one more” can go on endlessly. No check exists because whatever mind imagines can be taken seriously.
Antirealism has genuine insights. That there are limits to what we can know both inside and outside (and the latter for reasons more profound than merely scaling) comes naturally to antirealists. They understand why such limits are inevitable; a necessary (at least) core of consciousness. Modern realist thought (David Deutch, “The Beginning of Infinity”  perhaps the present poster child) too often mistakenly elides this truth. Limits apply on the outside because the fundamental structure of the external-in-itself includes that which is genuinely indeterminite, irregular (and not merely beyond the possibility of measurement), and on the inside for the reason well understood by antirealists; we cannot get out of the box.