Ernst Mach (1838–1916) — Empirio-Criticism and the Elimination of Metaphysics
This text is a preview of History of the Reception of Hegel, volume I, to be published in 2026 by Reflexivity Press.
Before Russell and analytic philosophy carried out their rebellion against metaphysics, Ernst Mach had already laid the philosophical groundwork. Mach was not an academic philosopher but a physicist and physiologist—yet his epistemological position had far-reaching consequences for twentieth-century philosophy. He formed the decisive bridge between the classical positivism of Auguste Comte and the logical empiricism of the Vienna Circle.
Biographical Context and Scientific Outlook
Ernst Mach served as professor of physics in Prague (1867–1895) and later in Vienna (1895–1901). His scientific work included significant contributions to mechanics, acoustics, and optics. The Mach number in aerodynamics, named after him, testifies to his empirical significance.[1]
Mach’s main philosophical work, The Analysis of Sensations and the Relation of the Physical to the Psychical (1886), developed a radically empiricist theory of knowledge. His goal was the “economy of thought”—science should confine itself to what is observable and eliminate all metaphysical additional assumptions. This demand for the elimination of superfluous entities is an empiricist variant of “Ockham’s razor.”[2]
The Basic Principle: Reduction to Complexes of Sensations
Mach’s central thesis was radically simple: the world consists of sensations (colors, sounds, pressures, warmth, smells, spaces, times, etc.). What we call “things” or “bodies” are relatively stable complexes of sensations. There is no underlying “substance,” no “thing in itself,” but only functional connections between sensations.[3]
This position had three radical consequences that became significant for the critique of Hegel:
The elimination of substance: The concept of “substance” as a persisting bearer of changing properties is metaphysically superfluous. What we call a “table” is a relatively stable complex of visual, tactile, and other sensations. The assumption of an invisible “substratum” explains nothing—it merely duplicates the explanation.
This argument repeats, on an empiricist basis, an insight that Hegel had already developed systematically in the logic of essence. Hegel’s analysis of “the thing and its properties” shows: if one removes all properties from the thing, an empty X remains—that is, nothing. The thing is nothing other than the totality of its properties.[4]
But whereas Hegel shows how this insight develops dialectically into more differentiated categories of mediation—from the thing via matter (the jumble of all properties) to force and its expression, then to inner and outer—Mach stops at mere elimination. For Hegel, the dissolution of substance is not the end of the analysis but leads to more precise determinations: the relation of force and its expression (force is nothing but its expression), then of inner and outer (both have the same content, only different form). This is not metaphysical speculation, but analysis of the structures that are implicitly at work in scientific thinking.
The elimination of causality: The concept of “cause” as a real force or a necessary connection is likewise metaphysical. What we call causality is merely the regular temporal succession of complexes of sensations. Science describes functional dependencies (y = f(x)), not mysterious “causes.”[5]
Here too Mach anticipates a critique that Hegel had already carried out systematically. In the logic of essence, Hegel develops causality from the formal through finite causality to infinite causality and then to reciprocal action. The naive notion of a one-sided “cause” is dissolved in favor of mutual constitution.
But whereas Mach leaves only empirical regularities standing, Hegel shows the systematic development of various structures of mediation: from external connection via inner affinity to teleological structure. Science does not in fact operate with naive causality, but it does operate with differentiated concepts of mediation—precisely those that Hegel developed.
The elimination of the self: Mach’s most radical consequence concerned the self. The “I,” too, is no persisting substratum, but a relatively stable complex of memories, feelings, and thoughts. Mach famously formulated: “The self is beyond salvation.” There is only the flux of sensations, no subject standing behind it.[6]
The Implicit Critique of Hegel — and Why It Hits a Caricature
Although Mach rarely mentioned Hegel directly, his position was aimed frontally at all speculative, non-empirical elements of thought. Yet Mach’s image of Hegel—like that of most analytic philosophers—was a caricature. He criticized a metaphysical distortion, not the actual Hegelian logic as we have reconstructed it.
Ironically, Mach and the analytic philosophers wanted to remove the metaphysical “clutter” from philosophy—but in doing so created new misunderstandings about Hegel that now need to be cleared away. The three main points of Mach’s implicit critique all hit misinterpretations:
1. The caricature of the “speculative method”: Mach assumed that Hegel wanted to deduce the development of logic “from pure concepts” (being, nothing, becoming)—as if concepts were independent entities that “move” mystically. This completely misses the performative structure of the logic (see Chapters 1.2, 8.4).
The reality: Hegel’s logic does not deduce “from concepts,” but explicates the structures that are already implicitly operative in rational practice. The “movement” is not mystical self-unfolding, but reflection on immanent contradictions that show themselves in the enactment of practice. When Mach must assume functional relations between sensations (which are themselves not sensations), he performs precisely the conceptual structuring that Hegel explicates.
2. The caricature of “absolute knowledge”: Mach read “absolute knowledge” as a claim to complete, perspective-less, divine cognition—the “pinnacle of metaphysical hubris.”
The reality: “Absolute knowledge” does not mean omniscience, but self-transparency of the forms of knowledge (see Chapter 24). It is insight into the structures through which cognition is possible at all—including the acknowledgment of its limits and perspectival character. The “absolute” is not the elimination of all perspectives, but their integration and mutual criticism (see Chapter 18.10 on the threefold permutation). Hegel’s “absolute knowledge” is closer to Mach’s own demand for the critical self-reflection of science than Mach suspected.
3. The caricature of “a priori structures”: Mach assumed that Hegel’s logic claimed knowledge independent of all experience—a pure construction of thought without empirical reference.
The reality: The logical categories are not “beyond” experience, but forms in which experience structures itself (see Chapter 11.8 on the resistance of experience). Logic is not an a priori metaphysics, but an explication of the structures of rational practice. It does not suspend experience but shows how experience can be conceptually articulated at all. When Mach speaks of “functional dependencies,” he uses exactly such structural concepts—which are themselves not observable, but order experience.
The systematic point: Mach’s critique refutes itself in the same way as his theory of sensations does: he must make non-empirical assumptions about structure (functional relations, scientific laws, his own epistemology) that go beyond individual sensations. Precisely what he criticizes in Hegel—conceptual structuring beyond immediate sensation—he himself performs, without reflecting on it.
The historical effect: This caricature was adopted and reinforced by the analytic tradition. Russell, Wittgenstein, and the Vienna Circle read Hegel through Mach’s lens—and fought a straw man. The task of contemporary Hegel interpretation is to clear away this “clutter” of misinterpretation and to show that the legitimate intuitions of the analytic philosophers (precision, empirical control, anti-psychologism) are not only compatible with an adequate interpretation of Hegel, but are already systematically developed within it.
Systematic Assessment: The Self-Contradictions of Radical Empiricism
Mach’s radical empiricism leads to self-contradictions. Its reduction to “complexes of sensations” cannot explain central phenomena:
1. The unity of experience: If there are only discrete sensations, how does the unity of experience arise? What holds sensations together into a coherent picture of the world? Mach must assume functional relations between sensations—but these relations are themselves not “sensations.” They are conceptual structures that order sensations.
2. The possibility of scientific lawfulness: Natural laws are general statements about functional connections. But generality cannot be observed. We observe individual cases and then infer general laws. The inductive inference from the particular to the general is not logically compelling—it presupposes structural assumptions that go beyond sensation.
3. The status of epistemology itself: Most problematically: Mach’s own theory asserts general truths about the structure of cognition. But this theory is itself not observable. It is a conceptual construction that goes beyond individual sensations. Empirio-criticism refutes itself by making non-empirical assertions.
Lenin’s critique: Vladimir Lenin recognized aptly in Materialism and Empirio-Criticism (1908) that Mach’s position collapses into subjective idealism. If there are only sensations, and these are “my” sensations, then the world exists only in my consciousness. This is Berkeley’s idealism in new guise—precisely what Mach wanted to avoid.[7]
The Legitimate Intuition
Despite these contradictions, Mach captured a legitimate intuition: the demand for empirical testability is an important criterion of scientific theories. Concepts that have no observable consequences are irrelevant to science. The elimination of superfluous metaphysical assumptions is methodologically legitimate.
Applied to Hegel: Mach’s critique hits a dogmatic image of Hegel that understands logic as a metaphysics of the in-itself. But the interpretation of Hegel developed here shows: Hegel’s logic is not a metaphysics existing independently of all experience. It is an explication of the structures that are implicitly at work in rational practice.
The “categories” of logic are not beyond experience, but forms in which experience structures itself. The dialectical “movement” is not mystical self-unfolding of concepts, but reflection on the immanent contradictions that show themselves in the enactment of practice. The “resistance of experience”[8] is a constitutive moment of logic, not an external disturbance.
Mach’s demand for empirical control can thus be integrated—but as a moment of a more comprehensive conception of rational practice, one that is not reduced to sensory observation.
Historical Impact: From Vienna to Cambridge and Back
Mach’s influence reached far beyond the borders of Austria-Hungary. His position formed the direct precursor to the Vienna Circle, whose members explicitly invoked Mach. Moritz Schlick, who founded the Circle, took over in 1922 the chair of “Philosophy of the Inductive Sciences” at the University of Vienna—precisely the chair that Mach himself had held and had advocated for.[9]
The connection to Cambridge was close: Bertrand Russell knew Mach’s works and shared his anti-metaphysical stance. Russell’s early works on the philosophy of mathematics and logic show Mach’s influence in the demand for the elimination of superfluous entities. The young Ludwig Wittgenstein, who studied with Russell in Cambridge from 1911–1913, read Mach and adopted his radical empiricism in modified form.
This line of tradition—from Mach via Russell and Wittgenstein to the Vienna Circle and back—shows the close interconnection of the emerging analytic philosophy. Mach was no isolated thinker but a node in an intellectual network that would shape twentieth-century philosophy.
His connection to the critique of Hegel is indirect but fundamental: he supplied the epistemological weapons with which Russell, Wittgenstein, and the Vienna Circle would combat “metaphysics”—and thus also Hegel. While Frege forged the logical tool, Mach supplied the empiricist motivation for the fight against metaphysics.
The intellectual exchange between Vienna and Cambridge fundamentally shaped the emerging analytic philosophy. Wittgenstein’s Tractatus Logico-Philosophicus (1921) was read by the Vienna Circle (in part mistakenly) as a manifesto of logical empiricism. The demand “Whereof one cannot speak, thereof one must be silent” seemed to complete Mach’s program of eliminating metaphysics by the means of modern logic.
Russell’s rebellion against the British Hegelians—which we consider in the next section—was inspired not only by Frege, but also by Mach’s radical empiricism. The combination of Fregean logic and Machian empiricism would shape analytic philosophy for decades.
Ernst Mach had significant influences on twentieth-century physics, among others on Einstein, who took into account Mach’s critique of absolute space and absolute time in developing the theory of relativity. ↩︎
Ernst Mach: The Analysis of Sensations and the Relation of the Physical to the Psychical, Jena: Fischer, 1886 (9th ed. 1922). ↩︎
Mach: Analysis of Sensations, Chapter 1: “Sensations as the Elements of the World.” ↩︎
G.W.F. Hegel: Science of Logic II (Logic of Essence), in: Works vol. 6, Frankfurt/M.: Suhrkamp, 1969, pp. 127–139 (“The Thing and Its Properties”). ↩︎
Mach: The Science of Mechanics: A Critical and Historical Account of Its Development, Leipzig: Brockhaus, 1883. Here Mach develops his critique of the concept of causality in the context of mechanics. ↩︎
Mach: Analysis of Sensations, Chapter 1, p. 20: “The self is beyond salvation.” ↩︎
Vladimir I. Lenin: Materialism and Empirio-Criticism. Critical Comments on a Reactionary Philosophy, Moscow 1908 (German edition: Berlin: Dietz, 1949). Lenin criticizes Mach, Avenarius, and their followers as subjective idealists. ↩︎
Froeb 2025, Chapter 11.8 ↩︎
Moritz Schlick was appointed in 1922 to the chair of “Natural Philosophy and Philosophy of the Inductive Sciences”—a chair that had been created for Mach and whose designation reflected Mach’s program. ↩︎