Beyond Physics and Metaphysics

Epistemics and the Differentiation of Reality into Subjective, Intersubjective, and Functional-Empirical Physics

Abstract

The classical distinction between physics and metaphysics has become increasingly inadequate for describing contemporary epistemic practice. While empirical physics is often implicitly treated as the sole standard of the real, subjective experience and social order are either reduced or relegated to an indeterminate metaphysical remainder. This paper proposes an alternative epistemic ordering.

Starting from Epistemics as a prior clarification framework, reality is not understood as a unified domain of objects, but as a configuration of distinct physics of stability: a subjective physics of experience, an intersubjective physics of social order, and a functional-empirical physics of effective constraints. These physics are neither ontological domains nor hierarchically ordered; they differ by their mechanisms of stabilization, load-bearing limits, and characteristic boundary signals.

Central to this ordering is the distinction between validity and stability. Epistemics clarifies in which physics a reality claim can be meaningfully raised and tested, that is, its physics of validity. Only within such a validity-physics can stability, robustness, and failure be determined. In this context, friction is analyzed as an epistemically legible boundary signal that makes limited load-bearing capacity visible without constituting an ontological principle.

Friction also functions as a selection mechanism over time. Different stabilization patterns generate different costs under strain, which stabilizes some structures while others are abandoned. In this way, core functions traditionally assigned to metaphysics can be fulfilled with greater epistemic precision, without formulating ultimate ontological claims. The focus shifts from whether something is real to the question under which validity conditions and stability limits reality claims can be meaningfully tested.

Keywords
Epistemics, relative reality, subjective physics, intersubjective physics, functional-empirical physics, friction, stability, critique of metaphysics, epistemology, differentiation of reality

Version: 05 February 2026
ORCID: 0009-0004-0847-9164
DOI: 10.5281/zenodo.18317966
© 2026 Stefan Rapp — CC BY-NC-ND 4.0

1. Why a New Division of Reality Is Necessary

For centuries, reality has been ordered along the distinction between physics and metaphysics. Physics has claimed the domain of the measurable, the law-governed, and the objective, while metaphysics was meant to address those questions that lie beyond empirical accessibility: meaning, being, consciousness, ultimate grounding. This division of labor was historically plausible, but it has become increasingly inadequate for contemporary epistemic practice.

The problem is not that metaphysical questions have disappeared. On the contrary, questions concerning consciousness, meaning, social order, or subjective experience are more present than ever. At the same time, classical metaphysics as a scientific frame of reference has lost much of its persuasive power. It is too closely associated with speculative, ontological, or even mythical elements, and its methodological criteria remain too unclear. What remains is a gap: central aspects of reality are causally effective, yet insufficiently situated within a scientific framework.

At the same time, it has become evident that empirical physics itself long ago began to do more than merely describe law-like natural relations. It operates with models, probabilities, observer-dependence, and system boundaries. Nevertheless, it is often implicitly treated as the sole standard of what may count as “real.” Subjective experience and social order then appear either as mere epiphenomena or as subordinate constructions lacking their own lawfulness.

This opposition generates a systematic distortion. Either reality is reduced to what is empirically measurable, or non-empirical reality is relegated to a metaphysical remainder that eludes scientific clarification. Neither approach does justice to the actual structure of our epistemic practice.

In everyday life as well as in science, we routinely operate with different forms of certainty. Some states of affairs count as real because they are immediately experienced. Others do so because they are socially recognized, institutionally stabilized, or normatively codified. Still others count as real because they are measurable, reproducible, or technically effective. These forms of reality do not stand in competition with one another; they overlap, support each other, and repeatedly come into tension. Yet so far there has been no systematic framework that takes this diversity seriously without either hierarchizing it or overburdening it metaphysically.

This paper therefore proposes an alternative ordering. In place of the classical division between physics and metaphysics, it introduces a differentiated conception of physics itself. Reality is no longer understood as a unified domain of objects, but as a configuration of distinct physics of stability: a subjective physics of experience, an intersubjective physics of social order, and a functional-empirical physics of scientific law-governed efficacy. Each of these physics follows its own rules, exhibits its own limits, and displays specific forms of stability and breakdown.

The proposed framework claims no ontological priority and introduces no hierarchical ordering of reality. It deliberately refrains from ultimate grounding, reduction, or unification. Instead, it understands itself as an epistemic structuring of real efficacy. Subjective, intersubjective, and functional-empirical stabilities are not played off against one another, but analyzed as different, equally legitimate modes of real load-bearing capacity, each with its own conditions of validity and characteristic boundary signals.

To sustain this distinction, however, an additional framework is required. The differentiation between different physics is itself not a physical finding, but an epistemic achievement. It presupposes that the conditions under which stability is claimed become explicit, as well as the points at which their limits are reached. These limits do not necessarily appear as permanent disturbances, but as the structurally unavoidable possibility of friction whenever stability is claimed under finite conditions.

Local reductions of friction are possible and empirically well documented; they shift load-bearing limits without abolishing the principled finitude of stable orders. In this sense, friction functions as a boundary signal of limited load-bearing capacity. It makes visible where models, orders, or stability claims must be examined, without itself constituting a principle of order or an ontological entity.

The clarification of these conditions is undertaken by Epistemics as a prior epistemic framework. Epistemics is not itself part of any physics. It does not describe experience, social order, or law-governed processes. Rather, it specifies the conditions under which spaces of physical stability become distinguishable, testable, and limitable. Epistemics does not stand alongside the physics, but precedes them as a condition of the possibility of recognizing reality in a differentiated way.

The aim of this paper is to develop this ordering systematically. First, the role of Epistemics as a prior epistemic framework is clarified. The three physics of reality are then outlined and distinguished in their basic structures. On this basis, it is shown how stability and boundary experience arise within each physics and what role friction plays as a signal of these boundaries. Finally, it is discussed to what extent this structure functionally replaces the classical roles of metaphysics without appropriating existential or normative questions.

The claim advanced in this paper is deliberately limited. It does not aim to provide ultimate reasons or final explanations. Instead, it seeks to make explicit the implicit presuppositions of contemporary epistemic practice. The proposed framework is not intended to force answers, but to clarify where answers are meaningful and where they are not.

Accordingly, this paper does not aim at a grounding of reality as such. Its focus lies on the analysis of the conditions under which different modes of reality remain stable, become effective, or reach their limits. The guiding question is not whether something is real, but under which conditions of validity and within which physics a reality claim can be meaningfully raised and tested.

The framework developed here does not stand in isolation. It is explicitly connected to the Theory of Relative Reality (RRT). RRT does not treat reality as a binary ontological predicate, but as a graded and domain-specific status determined along experiential immediacy, intersubjective stability, and functional efficacy. Against this background, the distinction between different physics of reality introduced in this paper is not to be understood as the introduction of new kinds of reality, but as a structural explication of those spaces of stability and validity that RRT already conceptually differentiates.

Talk of subjective, intersubjective, and functional-empirical physics does not denote independent ontologies. It refers to different modes of stabilizing real efficacy. This differentiation corresponds to the distinction of reality domains within the Theory of Relative Reality and serves to analyze their respective regularities, load limits, and boundary phenomena with greater precision. The aim is not to redefine the concept of reality, but to make visible how degrees and domains of reality manifest in epistemic practice as distinct spaces of stability.

In this sense, the present paper understands itself as a systematic elaboration of an RRT-compatible ordering model. It shifts the focus from the question of whether something is real to the question of in which physics, under which conditions of validity, and with which stability limits a reality claim can be meaningfully tested. Only on this basis can it be clarified which boundary experiences are readable as friction and what role epistemic ordering plays in coordinating different modes of reality.

2. Epistemics as a Meta-Framework of Reality

Before different physics of reality can be distinguished, it must first be clarified how it is determined at all what counts as real. This clarification does not constitute an additional physics. It concerns the conditions under which reality claims can be meaningfully formulated, assessed, and limited. The framework required for this purpose is referred to here as Epistemics.

Epistemics is not itself a form of reality and not a further physics. It does not describe experience, social order, or law-governed processes. Instead, it specifies the conditions under which such domains become epistemically distinguishable, testable, and assignable in terms of validity. Epistemics does not stand alongside the physics of reality, but precedes them as a condition of the possibility of differentiated recognition of reality.

Epistemics does not mean epistemology in the classical philosophical sense. It is not primarily concerned with the justification of knowledge claims or with theories of truth. Rather, it operates at a meta-epistemic level as a structural framework for the assignment of validity, the formation of models, and the interpretation of boundary phenomena. Its function is not to generate knowledge claims, but to clarify the conditions under which claims to reality can be meaningfully raised, tested, revised, or rejected across different domains.

In this sense, Epistemics refers not to individual items of knowledge, but to the structure of epistemic processes through which reality is modeled, stabilized, and revised. It encompasses the rules according to which observations count as relevant, models are constructed, validity claims are raised, and limits of applicability become visible. Epistemics does not describe what is effective, but how it can be recognized that something is effective.

This prior status is essential to avoid category mistakes. If Epistemics were treated as part of a subjective physics, epistemic operations would be reduced to inner phenomena. If it were treated as an empirical discipline, it would lose its clarifying and ordering function. Epistemics is neither subjectivist-psychological nor natural-scientific. It is meta-epistemic: it structures the conditions under which subjective, intersubjective, and functional-empirical realities become distinguishable, assessable, and limitable in the first place.

Epistemics can be characterized by three core functions.

First, it clarifies validity. Not everything that is experienced, asserted, or measured is thereby epistemically valid. Epistemics specifies the criteria under which validity claims can be meaningfully raised and examined. These criteria differ depending on the physics of reality involved, but they follow a shared logic of justification, testability, and stabilization.

Second, Epistemics structures model formation. Epistemic access to reality is always mediated by models. These models are selective, simplifying, and purpose-relative. Epistemics analyzes how such models arise, why they remain stable under certain conditions, and under which forms of strain they must be revised. Model-dependence is not treated as a deficiency, but as a necessary condition of finite epistemic systems.

Third, Epistemics marks boundaries. Every epistemic model reaches points at which its explanatory capacity is exhausted, its assumptions become inconsistent, or its stabilization fails. Epistemics interprets such boundary phenomena not as mere error, but as structurally informative signals indicating that different physics possess different load-bearing limits.

Epistemics is not freely norm-setting. Its ordering activity is structurally reactive. It becomes operative where friction appears. Boundary stresses, costs, conflicts, and overextensions force implicit assumptions to be made explicit and domains of validity to be clarified. Epistemics does not generate these frictions. It reads them as epistemically legible boundary signals.

In this sense, Epistemics does not function as a superior decision-making authority. It does not resolve conflicts between physics or decide priorities. Its role is diagnostic and coordinative: to explicate conflicts, expose trade-offs, and make the costs of stabilization visible without converting them into truth claims or normative verdicts.

From this perspective, Epistemics is not a competing domain of reality, but an ordering achievement that makes multiple domains of reality simultaneously intelligible. It enables subjective experience, social order, and functional-empirical constraints to be taken seriously at the same time without reducing them to one another or arranging them hierarchically.

Crucially, Epistemics does not provide ultimate grounding. It does not answer why there is reality or cognition at all. Instead, it clarifies under which conditions epistemic operations are meaningful and where their reach necessarily ends. This self-limitation is not a weakness, but a condition of epistemic integrity.

With Epistemics established as a meta-framework, the conditions are in place to understand the physics of reality introduced in the next chapter not as competing worldviews, but as equally legitimate yet structurally distinct spaces of stability. Only on this basis can it be stated precisely what is meant by subjective, intersubjective, and functional-empirical physics and how their respective efficacy and limits are to be determined.

The framework developed here stands in substantive proximity to several established positions in contemporary philosophy without merging with them. With pragmatist approaches, it shares an emphasis on efficacy and load-bearing robustness rather than ontological ultimate grounding. With scientific perspectivism, it shares the insight into the inevitability of model-dependent cognition. With social-ontological and systems-theoretical approaches, it shares the analysis of stabilized social orders.

At the same time, the present approach differs from related positions in three decisive respects. First, reality is systematically differentiated into distinct physics of stability without introducing a hierarchical ordering among them. Second, truth is explicitly bound to domain-specific stability under the relevant forms of strain, and the truth question is logically subordinated to the question of validity, since claims become truth-apt only within a clarified physics of validity. Third, friction is introduced as an epistemically legible boundary signal that renders the load limits of models and orders visible without functioning as an independent ontological principle. Taken together, this configuration enables a precise coordination of plural modes of reality without reducing them, dissolving them into relativism, or re-ontologizing them.

3. The Three Physics of Reality

On the basis of Epistemics as a meta-framework, reality can no longer be described as a unified domain of objects. Instead, it becomes apparent that different domains of reality follow their own forms of stability, load-bearing capacity, and boundary formation. In order to capture these differences with analytical precision, the following discussion speaks of different “physics of reality“.

The term physics is not used here in the narrow natural-scientific sense. It is used as a structural concept for rule-governed spaces of stability with limited load-bearing capacity, in which constraints cannot be arbitrarily suspended and become visible at characteristic boundary signals.

Mathematical formalization, quantification, or universal lawhood may be present in some physics, most notably in empirical physics, but they are neither defining nor required features of a physics as such. What is decisive is not formal expressibility, but the existence of non-arbitrary constraints, mechanisms of stabilization, and epistemically readable boundary phenomena.

In the present usage, a physics exists only if three conditions are fulfilled. First, there must be a character of constraint or resistance that cannot be arbitrarily ignored or suspended. Second, stability must be generated and maintained through specific mechanisms, such as functional efficacy, social recognition, or subjective coherence. Third, characteristic boundary signals must occur at which overextension, instability, or failure become visible. Mere regularity or repetition is not sufficient. The concept of physics thus denotes not an arbitrary order, but a structurally limited space of stability with testable load-bearing capacity.

The distinction between different physics of reality does not introduce new ontologies. It serves the analysis of different spaces of stability and validity of real efficacy, as they are also distinguished within the framework of the Theory of Relative Reality. In what follows, three such physics are distinguished: a subjective physics of experience, an intersubjective physics of social order, and a functional-empirical physics of law-governed efficacy. This differentiation is neither ontological nor hierarchical. None of the three physics is more fundamental than the others, and none can be fully reduced to another. Their difference arises from the manner in which stability is generated, maintained, and lost.

3.1 Subjective Physics: Regularities of Experience

Subjective physics describes the regularities under which experience itself remains stable. These include attention, temporal structuring, decision-making capacity, emotional load-bearing, and coherence of meaning. These dimensions are not freely selectable, but follow structured constraints. Overload, doubt, exhaustion, or loss of meaning are therefore not merely moods or psychological contingencies, but epistemically readable signals that subjective stability is reaching its limits.

It is important to emphasize that subjective physics is not understood in an idiographic or psychological sense. It does not describe individual peculiarities, personality traits, or empirically measurable psychological variables of particular subjects. Rather, it refers to structurally functional conditions of experience as such, that is, to those regularities that limit, enable, and organize any form of experience whatsoever.

That attention is finite, that decisions require exclusion, or that experience is temporally structured are not contingent properties of individual psyches, but general conditions of stability of subjective reality. Subjective physics therefore does not describe psychological contents, but the formal load limits and invariances under which experience remains stable or breaks down.

In this sense, subjective reality is genuinely efficacious, even though it cannot be instrumentally measured or externalized. Its effects manifest directly within experience itself, for example as overload, inner tension, decisional paralysis, or loss of meaning. These manifestations are not secondary interpretations, but immediate indicators that subjective stability is reaching or exceeding its load-bearing limits.

Subjective reality counts as stable as long as these conditions are fulfilled. When its robustness is exceeded, this becomes immediately apparent in experience itself. In this sense, subjective physics is really efficacious even though it cannot be instrumentally measured.

3.2 Intersubjective Physics: Regularities of Social Order

Alongside subjective experience, there exists a second form of reality that is neither individual nor natural-scientific: social order. Money, law, roles, institutions, responsibility, or status are not merely conventional agreements, but stabilized structures with their own efficacy. They follow an intersubjective physics in which expectations, permissions, and obligations generate real constraints and consequences, independent of individual assent.

Intersubjective stability must not be equated with voluntariness or arbitrariness. Social orders generate real constraints by structuring expectations, scopes of action, and consequences in a durable way. Legal obligations, economic dependencies, or institutional responsibilities continue to exert force even when they are individually contested or subjectively denied.

In this sense, intersubjective physics overlaps with functional efficacy without being reducible to it. Its constraints are not law-like in the natural-scientific sense, yet they are persistent, load-bearing, and associated with real costs. Violations of social order do not remain without effect, but produce specific forms of social friction such as sanctions, exclusion, or loss of trust. It is precisely this constraint structure that distinguishes stable intersubjective reality from merely situational agreements or private convictions.

This physics describes the conditions under which social order remains stable. Trust, legitimacy, recognition, and coherence of expectations function here as central stabilization variables. Social systems may persist, transform, or collapse without this being reducible to individual psychology or to functional-empirical processes. Stability and breakdown are determined by the load-bearing capacity of these intersubjective structures under strain.

Conflict, loss of power, or norm violation are not treated here as moral categories, but as phenomena of intersubjective stability. They indicate that expectations, roles, or institutional arrangements no longer carry under relevant strain. In this sense, conflict and breakdown function as epistemically readable boundary signals of intersubjective physics, revealing limits of coordination rather than failures of individual actors.

By using physics here as a structural concept for rule-governed, limited, and friction-laden stability, the boundary character is preserved but more precisely localized. Constraint, robustness, and failure are no longer attributed exclusively to nature, but are situated where they are factually effective: in experience, in social orders, and in functional systems. The concept of physics thus does not lose sharpness, but gains explanatory reach without abandoning its limiting function.

3.3 Functional-Empirical Physics: Regularities of Functional Efficacy

Functional-empirical physics describes those forms of reality in which stability appears as functional resistance to intervention, neglect, or reinterpretation. Its defining feature is not measurability as such, but sustained efficacy under relevant demands. Empirical physics in the narrower natural-scientific sense constitutes a paradigmatic special case of this functional physics, characterized by measurability, reproducibility, and mathematical formalization. These features confer particular epistemic robustness, but do not establish an ontological priority over subjective or intersubjective physics.

Many real phenomena are entanglements of multiple physics. The differentiation proposed here therefore treats physics not as classes of objects, but as analytical axes. The functional-empirical aspect of a phenomenon designates those constraints that persist independently of social recognition, such as energy requirements, resource scarcity, capacity limits, or technical dependencies. Intersubjective aspects, by contrast, are stabilized through recognition, institutions, trust, and normative coordination.

This analytical distinction makes it possible to examine complex phenomena such as economic dynamics, technical infrastructures, or legal orders with precision, without denying their real entanglement or blurring the physics themselves.

Functional-empirical physics is epistemically privileged only in a limited and context-bound sense. Its stabilities are particularly well intersubjectively testable and technically exploitable, which grants them high operational reliability. This privilege, however, does not establish an ontological priority. Functional efficacy indicates what enforces itself through persistent resistance, not what is thereby more real than other forms of stability. The limits of functional-empirical physics become visible where functional explanations, though correct, cannot account for the emergence, maintenance, or breakdown of meaning, responsibility, or social order.

3.4 Criteria of Distinction

The differentiation of the three physics does not rest on different kinds of objects, but on different criteria of stability. In functional-empirical physics, stability is bound to functional efficacy, which in the special case of empirical physics manifests as law-governed reproducibility.

These criteria are epistemically distinguishable, but in practice always entangled. A social system may function empirically while becoming subjectively or intersubjectively unstable. Conversely, subjective or social stabilities can be maintained even when they are empirically inefficient or costly.

It is precisely this entanglement that explains why reality cannot be described along a single physics. An adequate analysis instead requires taking each physics seriously in its own logic.

With this differentiation, the framework is in place to clarify, in the next step, how limits and loads become visible within the individual physics. These boundary phenomena appear in different forms, but they fulfill a common function. They will be analyzed systematically under the concept of friction.

The differentiation of physics presupposes a prior question of validity. Before stability, truth, or friction can be addressed, it must be clarified in which physics a reality claim can meaningfully be tested at all.

Many apparent conflicts do not arise from contradictory findings, but from claims being assessed outside their respective physics of validity. Subjective experiences are then evaluated functionally, functional constraints are treated as mere interpretations, or social stabilities are mistaken for empirical facts. The explicit clarification of validity counters such domain-transfer errors and provides the condition for reading friction correctly as a physics-specific boundary signal.

Validity, in this sense, denotes the domain-appropriate testability of a claim. It clarifies in which physics a reality claim can meaningfully be raised and examined, and is thus logically prior to any assessment of truth or stability. Without clarified validity, any attribution of truth remains categorically underdetermined. Many apparent truth conflicts can be traced back to missing or erroneous assignments of validity.

4. Friction as a Boundary Signal Within the Physics

Once the different physics of reality have been distinguished and their respective criteria of stability have been specified, the question arises of how their limits become epistemically visible. These limits do not appear abstractly, but in concrete situations of strain. In what follows, the term friction designates those physics-specific manifestations in which claims to stability encounter their load limits under relevant challenges. Friction is not an independent causal principle or an ontological entity, but an epistemically readable boundary signal through which the robustness of a claim becomes assessable within its domain of validity.

Accordingly, friction does not denote a lack of organization or an avoidable loss through resistance. It is the necessary consequence of the fact that every physics can sustain stability only within limited capacities. Friction does not appear as an object alongside the physics, but as a relational phenomenon within their respective logics of stability. Its epistemic comparability does not arise from identical causes, but from its shared function as a boundary signal of limited robustness.

4.1 Friction Is Necessary, Not Contingent

In all three physics, the following holds: stability is possible only as long as strains remain within certain limits. When such a limit is reached or exceeded under relevant demands, this becomes visible as friction. Friction is not to be understood as a permanently present fact, but as a structurally unavoidable possibility whenever stability is claimed under finite conditions.

Local reductions of friction are possible in all physics, for example through technical optimization, institutional design, or subjective routinization. Such reductions, however, do not alter the fundamental function of friction as a boundary signal. They shift load limits without abolishing the principled finitude of stable orders. In this sense, friction does not mark the failure of order, but the conditions of its robustness.

4.2 Physics-Specific Forms of Friction

Although friction becomes visible in all physics, it takes different forms in each.

In subjective physics, friction appears as overload, inner tension, doubt, exhaustion, or loss of meaning. These phenomena are not merely feelings, but structural indications that attention, decision-making capacity, or meaning integration are reaching their limits. Subjective friction is immediately experienced and cannot be externalized.

In intersubjective physics, friction manifests as conflict, loss of trust, crises of legitimacy, or social disintegration. Here it becomes evident that expectations can no longer be coordinated or that institutional structures lose their stabilizing function. This friction is neither purely subjective nor empirically measurable, yet it is real and often highly persistent.

In empirical physics, friction appears as a physical boundary: energy expenditure, temporal delay, material fatigue, increase of entropy, or computational complexity. These forms of friction are quantitatively describable and technically addressable, but never fully eliminable.

4.3 The Epistemic Legibility of Friction

Although friction manifests in physics-specific ways, it is epistemically comparable. In all cases, it signals that a model, an order, or a stabilization is reaching its limit. Friction thus serves as a central corrective against model overextension.

It is important not to equate friction with failure. Friction does not necessarily mark the end of a system; it can also be the starting point of adaptation, revision, or transformation. Epistemically, friction is therefore not a disturbance signal, but an information signal about the structure of the reality in which a system operates.

In this sense, friction cannot be separated from the concept of truth, but this relation is strictly mediated by validity. Truth does not appear as immediate correspondence, but as domain-specific stability under the forms of challenge relevant to a given physics. Only where the validity of a claim has been clarified can friction function as a meaningful test of robustness. Friction therefore does not generate truth by itself; it renders visible whether a claim remains stable within its assigned domain of validity or must be revised or abandoned.

Beyond its function as a boundary signal, friction operates as a selection mechanism. Because different models, orders, or practices generate different costs under strain, certain structures are stabilized while others are discarded. Friction thus generates cost differentials; these cost differentials select robustness, and selected robustness binds meaning over time.

In this sense, reality does not arise through mere positing or construction, but through proven stabilization under repeated strain. This logic of selection applies across all physics, albeit in different forms. Friction is therefore not a mere disturbance phenomenon, but the mechanism by which contingent possibilities are transformed into stable reality. This test of stability, however, always presupposes a prior assignment of validity; without it, friction-based truth remains categorically underdetermined.

4.4 Friction and Model-Dependence

Friction does not arise absolutely, but relative to stabilized models and their claims to validity. A given situation may generate significant friction within one model while remaining robust within another, without this implying arbitrariness. The boundary exists independently of the model, but it becomes epistemically legible only where a model asserts stability under specific conditions. Friction therefore reveals not merely resistance, but the point at which a model’s validity claim encounters limits within its assigned physics.

This model-relativity explains why friction is experienced differently across historical and cultural contexts without calling its structural necessity into question. Epistemically decisive is not the avoidance of friction, but the recognition of which models generate which frictions and which frictions are bearable.

4.5 Friction as Protection Against Arbitrariness

Finally, friction fulfills a fundamental ordering function by preventing reality-claims from becoming arbitrary. Without friction, there would be no constraint on stabilization, no necessity of coordination, and no limit to the expansion of validity claims. Friction forces systems to prioritize, to expose costs, and to justify their stability under strain. In this sense, friction is not opposed to order, but constitutes its condition: it makes visible that every form of stability entails effort and exclusion, and that attempts to eliminate friction entirely tend to displace instability rather than resolve it.

In the next chapter, it will be shown what consequences this insight has for the status of classical metaphysics and to what extent Epistemics and differentiated physics assume its central functions without closing the open questions of philosophy.

4.6 Conflicts Between Physics and Epistemic Coordination

Because the different physics of reality each possess their own criteria of stability and boundary signals, their claims can come into conflict in concrete situations. Such conflicts are not signs of theoretical inconsistency, but a necessary consequence of plural spaces of stability. They cannot be resolved ontologically, but they can be coordinated epistemically.

Such coordination proceeds in four steps. First, a validity assignment must be made: it must be clarified in which physics a given claim can meaningfully be tested. Second, a domain-specific stability test must be applied, determining which forms of strain are relevant in the respective physics. Third, emerging trade-offs must be explicitly identified, that is, those situations in which stability in one physics can be maintained only at the expense of another.

Fourth, it must be noted that decisions in such conflict situations do not constitute truth judgments. They are acts of prioritization of a practical, political, or ethical kind. Epistemics does not make these decisions itself, but ensures that they become visible as decisions, that their presuppositions are disclosed, and that their costs remain nameable.

This form of coordination avoids both trivializing conflicts between physics as mere misunderstandings and resolving them through concealed hierarchizations. Instead, such conflicts are acknowledged as structural tensions that require explicit and responsible prioritization.

The concept of friction is used in this text deliberately in a functional and structural sense. The aim is not its exhaustive theoretical elaboration, but its systematic positioning within the differentiated physics of reality. The analysis developed here shows the role of friction as a boundary signal and selection mechanism for stability, validity, and coordination. A more comprehensive development of friction as a general selection mechanism is provided in a separate companion paper, where the concept is elaborated in detail without altering the ordering framework established here.

5. Metaphysics – Functional Dissolution Instead of Ontological Replacement

The preceding analysis suggests that many problems traditionally attributed to metaphysics have not disappeared, but have been misallocated. Classical metaphysics aimed to determine what is ultimately real, how different domains of reality relate to one another, and where the limits of cognition lie. It is precisely in these functions, however, that metaphysics has lost epistemic plausibility. Ontological ultimate claims, speculative unification, and insufficiently specified boundary criteria have increasingly undermined its explanatory role within contemporary epistemic practice.

The ordering developed here does not aim to replace metaphysics with a new ontological system. Instead, those functions historically ascribed to metaphysics are epistemically specified and distributed across different levels of analysis. This means that certain tasks traditionally assigned to metaphysics are reallocated more precisely and methodologically re-anchored, without being bundled into a single concept of being.

5.1 Boundary Clarification Without Ultimate Grounding

One central function of metaphysics has always been boundary clarification: What can be known, and what cannot? In the proposed ordering, this task is not performed ontologically, but epistemically. Epistemics marks the conditions under which cognition operates meaningfully and makes visible where models lose their robustness. Friction functions here as a boundary signal, not as a metaphysical abyss.

What is decisive is that this boundary marking deliberately refrains from ultimate grounding. It does not answer the question of why there is reality or cognition at all, but clarifies under which conditions statements about reality are meaningful. This self-limitation is not a loss, but an epistemic gain. It prevents epistemic limits from being misinterpreted as ontological deficiencies or metaphysical deficits.

5.2 Unification Through Structure Rather Than Being

Metaphysics traditionally sought a unity of reality by appeal to an underlying ontological ground, such as substance, principle, or ultimate being. The ordering developed here replaces this ontological unification with a structural one. Unity does not arise from reduction to a common essence, but from the shared logic according to which different physics are stabilized, strained, and selected under finite conditions. Reality is unified not by being the same, but by being comparably constrained.

This structural unity has a dynamic dimension, which manifests as selection under friction, and an epistemic dimension, which appears as coordination, distinction, and limitation through Epistemics. The three physics of reality are not isolated, but are related to one another through Epistemics. Their unity does not consist in their reducibility to one another, but in the fact that they are distinguished, stabilized, and limited according to the same epistemic rules. Unity thus arises not through reduction, but through coordinated differentiation.

5.3 Order Without Ontologization

Another central concern of metaphysics was the explanation of order. Why does the world appear structured rather than chaotic? In the perspective proposed here, order is not understood as an ontological property of the world, but as the result of stabilized physics. Order is real because it is effective, not because it is metaphysically grounded.

This shift has an important consequence. Order is neither absolute nor arbitrary. It is robust, changeable, and context-dependent. Friction marks precisely this dynamic by indicating where stability comes under pressure. Order thus becomes explainable without being absolutized, and criticizable without being relativized.

5.4 What Deliberately Remains Open

Not all questions traditionally attributed to metaphysics are answered by this ordering. Existential questions of meaning, normative commitments, and ultimate “why” questions remain deliberately open. They cannot be derived from the physics or from epistemics without committing a category mistake.

This openness is not a deficiency, but a consequence of epistemic integrity. By not overburdening these questions metaphysically, they retain their genuinely philosophical character. They continue to belong to philosophy, but no longer to metaphysics in the classical sense. Openness here does not mean an empty space of content, but a conscious separation between epistemic analysis and normative commitment.

5.5 The Philosophical Gain of Functional Dissolution

The functional dissolution of metaphysics makes it possible to take subjective experience, social order, and empirical lawfulness scientifically seriously without ontologically conflating them or distorting them hierarchically. Philosophy does not lose depth through this move, but gains precision. Its focus shifts from speculative ultimate grounding to clear work on boundaries, structures, and concepts.

Metaphysics is thus not refuted, but translated into its viable functions. What remains is not a void, but a clear framework that explains why certain questions are answerable and others must necessarily remain open.

6. Differentiating Reality, Relieving Metaphysics

This paper began from the observation that the classical distinction between physics and metaphysics no longer adequately captures contemporary epistemic practice. Treating empirical physics as the sole standard of reality either reduces subjective experience and social order or relegates them to an indeterminate metaphysical remainder. The differentiated framework developed here replaces this opposition with a structured plurality of physics of stability, coordinated by Epistemics rather than unified ontologically. In doing so, it preserves the epistemic seriousness of empirical science while allowing subjective and intersubjective realities to be analyzed as genuinely effective, yet domain-specific, forms of stability.

The precondition for this differentiation is Epistemics as a meta-framework. Epistemics does not stand alongside the physics, but precedes them. It clarifies under which conditions something counts as real, how models are formed and stabilized, and where their limits lie. In doing so, it functionally assumes those boundary- and ordering-related tasks that were traditionally attributed to metaphysics, without resorting to ontological ultimate claims.

Within this framework, friction was analyzed as a central boundary signal. Friction is neither a defect nor an avoidable loss through resistance, but the structurally unavoidable possibility of boundary strain under finite conditions of stability. It becomes visible where a physics reaches its limits of robustness under relevant demands and thereby makes clear that stability is always bound up with effort, selection, and exclusion. Friction is physics-specific, yet epistemically legible. It connects subjective experience, social order, and empirical lawfulness without conflating them.

From this perspective, it becomes clear that many classical problems of metaphysics are not resolved, but must be re-situated. Boundary clarification, unification, and the description of order can be performed more precisely in epistemic and structural terms. Existential questions of meaning, normative commitments, and ultimate “why” questions deliberately remain open. They are not displaced, but protected from false physical or ontological appropriation.

The philosophical gain of this ordering lies in its limitation. It does not claim ultimate grounding, but clarity about what can be explained and what cannot. Precisely in this way, it creates a stable framework in which subjective experience, social reality, and empirical knowledge can be taken scientifically seriously without losing their respective internal logics.

Accordingly, this paper understands itself not as a conclusion, but as a foundation. The differentiation developed here enables current and future debates about technology, society, and knowledge to be conducted with greater precision, because it makes explicit which physics is addressed in each case and which form of friction becomes relevant. Reality thus appears not as a metaphysical riddle, but as a structured, finite, and robust order: differentiated yet coherent, and thereby compatible with ongoing debates in philosophy of science, social philosophy, and technology assessment.

Canonical Framework

Adoption of the Epistemics Core Canon
This paper explicitly adopts the canonical framework established in the Epistemics base paper (Epistemics: Model Management Under Finite Conditions). The canonical definitions provided there serve as the unchanged reference basis for the present work. The meanings of all core canonical terms are preserved and are neither redefined nor implicitly modified.
The adopted core canon includes, in particular, the concepts of Epistemics, model, validity, domain, stabilization, costs, revision, overextension, and malfunction, as defined in the base paper. These concepts retain their original functional scope and serve as the background architecture against which the differentiation of physics and the role of friction are developed in this paper.
No competing or alternative definitions of these canonical terms are introduced.

Canonical Deviations or Refinements
This paper introduces no deviations, reinterpretations, or refinements of the Epistemics core canon. All canonical terms are used strictly in the sense defined in the Epistemics base paper. The scope, function, and validity conditions of the adopted canonical concepts remain fully unchanged.

Paper-Specific Canon Extensions
In addition to adopting the Epistemics core canon, this paper introduces a set of paper-specific canonical extensions. These concepts do not alter the meaning of the core canon but specify how reality is differentiated into distinct physics of stability and how validity, stability, and boundary phenomena are to be interpreted within those physics.
The following terms are introduced and stabilized for the purposes of this paper:

Subjective physics
Subjective physics designates the space of stability in which reality is constituted through experiential coherence, decisiveness, and meaning integration under finite conditions. It refers to rule-governed regularities of experience that exhibit characteristic load limits and boundary phenomena, such as overload, doubt, or loss of meaning. Subjective physics is not psychology and does not denote empirical measurement of mental states.

Intersubjective physics
Intersubjective physics designates the space of stability in which reality is constituted through social recognition, coordination, institutional persistence, and legitimacy. It describes the regularities governing social order, including trust, normativity, and role structures, and the characteristic boundary phenomena through which social stability breaks down, such as conflict or loss of legitimacy.

Functional-empirical physics
Functional-empirical physics designates the space of stability in which reality is constituted through functional efficacy under resistance. It refers to constraints that assert themselves independently of individual experience or social consent. Empirical physics in the narrow natural-scientific sense is treated as a paradigmatic special case of functional-empirical physics.

Physics of reality
Physics of reality denotes one of the differentiated spaces of stability within which reality claims can be meaningfully raised, tested, and limited. The concept is used structurally, not ontologically, and introduces no hierarchy among the different physics.

Validity-assignment across physics
Validity-assignment across physics refers to the epistemic clarification of the physics within which a given reality claim can be meaningfully tested. Validity is logically prior to truth and determines which forms of stability testing and which boundary phenomena are relevant.

Canonical Status and Scope
The paper-specific concepts introduced here constitute an explicit canonical extension of the Epistemics framework. They are stabilized for the scope of this paper and may serve as reference concepts in subsequent work, provided their use is explicitly indicated.
No silent extension, reinterpretation, or retroactive modification of the Epistemics core canon occurs. Any future deviation, refinement, or further extension must be explicitly marked in accordance with the meta-rule governing canonical development.

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