Lenin’s philosophical masterwork (1909) — the defence of dialectical materialism against Machism, idealism, and philosophical revisionism
Materialism and Empirio-Criticism: Critical Comments on a Reactionary Philosophy was written by V. I. Lenin in 1908 and published in 1909. It is the most important philosophical work in the Marxist-Leninist canon after Engels’s Anti-Dühring and Ludwig Feuerbach. It is not merely a polemic against obscure Russian intellectuals — it is the definitive statement of the Marxist theory of knowledge, the relationship between matter and consciousness, and the partisan character of all philosophy.
Lenin wrote the book during one of the darkest periods for Russian social democracy. The 1905 Revolution had been defeated. Reaction ruled. And within the ranks of the Bolsheviks themselves, a group of intellectuals — led by Alexander Bogdanov, Anatoly Lunacharsky, and Vladimir Bazarov — had begun importing the philosophy of Ernst Mach and Richard Avenarius into Marxism, attempting to “update” its philosophical foundations. Lenin recognised this for what it was: a retreat from materialism into idealism, dressed up in fashionable scientific language.
The book’s central argument is devastatingly simple: there are only two camps in philosophy — materialism and idealism. Every attempt to find a “third way,” every claim to have transcended this division, every purportedly neutral epistemology inevitably falls into one camp or the other. Empirio-criticism, for all its scientific pretensions, falls into idealism — and idealism, in the context of the workers’ movement, serves reaction.
The defeat of the 1905 Revolution ushered in a period of savage reaction under Prime Minister Pyotr Stolypin. Revolutionary organisations were smashed, militants were hanged, and the working class was driven underground. In this atmosphere of demoralisation and defeat, many intellectuals who had rallied to the revolutionary cause during the uprising now retreated — not only politically but philosophically.
Alexander Bogdanov was one of the most prominent Bolsheviks, second only to Lenin in the faction’s leadership. He was also a physician, science fiction writer, and philosopher who had developed his own system of thought — “empiriomonism” — drawing heavily on the positivist philosophy of Ernst Mach and Richard Avenarius. Mach held that science should concern itself only with “sensations” and their functional relationships, rejecting the concept of matter as an independent reality behind sensations. Avenarius developed a parallel doctrine he called “empirio-criticism” — the “criticism of experience.”
Bogdanov, joined by Bazarov, Lunacharsky, Yushkevich, Valentinov, and others, argued that Marxism needed a new philosophical foundation. They claimed that Marx and Engels’s materialism was “outdated” and that Mach’s philosophy of “pure experience” could provide a more scientific grounding. Some, like Lunacharsky, even flirted with “God-building” (bogostroitelstvo) — the creation of a new socialist religion.
Lenin understood that this was not an innocent academic exercise. Philosophical revisionism was the thin end of the wedge. If the party abandoned materialism, it would lose its scientific foundation — its ability to analyse the world objectively and act upon it. He spent months in the libraries of Geneva and London, systematically studying Mach, Avenarius, Berkeley, Hume, and the latest developments in physics, in order to demolish the Machist position root and branch.
“The philosophy of the scientist Mach is to natural science what the kiss of the Christian Judas was to Christ. Mach likewise betrays natural science to fideism... Mach’s philosophy and that of the empirio-critics is a screen behind which fideism takes refuge.”— V. I. Lenin, Materialism and Empirio-Criticism, 1909
The book comprises six chapters, an introduction, and a supplement. Each chapter builds upon the last to construct a comprehensive defence of materialist epistemology.
Lenin begins by examining the central claim of Mach and Avenarius: that the world consists of “elements” or “sensations,” and that the distinction between the physical and the mental is merely one of functional arrangement, not of substance. Mach wrote that “bodies are complexes of sensations” — that a table is not a material object existing independently of our perception, but a cluster of colours, textures, resistances, and shapes that we label “table.”
Lenin demonstrates that this position is simply a repetition of George Berkeley’s subjective idealism from the eighteenth century. Berkeley had argued that “to be is to be perceived” (esse est percipi). Mach says exactly the same thing in new terminology. The “elements” are just Berkeley’s “ideas” with a coat of scientific paint.
“Once you deny objective reality, given us in sensation, you have already lost every weapon against fideism, for you have slipped into agnosticism or subjectivism — and that is all that fideism requires.”— V. I. Lenin, Materialism and Empirio-Criticism, Ch. I
The chapter establishes the fundamental divide: materialists hold that matter is primary and consciousness secondary — that the material world exists independently of any mind and is reflected, however imperfectly, in our sensations. Idealists hold that consciousness, sensation, or “experience” is primary, and that matter is either a construct of the mind or an unknowable “thing-in-itself.” There is no middle ground.
This chapter contains Lenin’s most celebrated philosophical contribution: his definition of matter.
“Matter is a philosophical category denoting the objective reality which is given to man by his sensations, which is copied, photographed and reflected by our sensations, while existing independently of them.”— V. I. Lenin, Materialism and Empirio-Criticism, Ch. II
This definition is crucial because it separates the philosophical concept of matter from any particular physical theory of matter. When physicists discovered that atoms were not indivisible, or that mass could be converted to energy, some philosophers claimed that “matter has disappeared.” Lenin refutes this: what disappears is not matter but the particular level of knowledge we had about matter. Matter as objective reality — as that which exists independently of consciousness — cannot disappear.
Lenin defends the materialist position that sensations, perceptions, and ideas are reflections, images, or copies of objectively existing things. This does not mean a mechanical, mirror-like reproduction. The reflection is always approximate, always being refined and deepened through practice and science. But it is a reflection of something real — not a construction of the mind from its own internal resources.
Against the Machist claim that we can only know sensations, never things “behind” them, Lenin insists: sensations are produced by the action of objectively existing objects upon our sense organs. To deny this is to make nonsense of all science and all practical life. If sensations are not reflections of an external world, then the distinction between science and fantasy, between truth and delusion, collapses entirely.
Lenin, following Engels, treats consciousness as a product of highly organised matter — specifically, of the human brain. Consciousness does not exist independently of matter; it is a property of matter at a certain stage of development. This is philosophical materialism applied to the mind: there is no soul, no spirit, no consciousness floating free of material organisation. As this site argues in Everything is Physics, consciousness is computation — a physical process occurring in a physical substrate.
The third chapter addresses the question of truth. Lenin distinguishes between absolute truth and relative truth, and insists on the dialectical relationship between them.
The objective content of human knowledge that is not dependent on the subject and does not change with the development of science. That the Earth revolves around the Sun, that water is H₂O, that human beings evolved from earlier primates — these truths, once established, are not overturned by subsequent discoveries. They are grains of absolute truth.
Every concrete, historically conditioned formulation of knowledge is relative — it is approximate, incomplete, liable to be superseded by a deeper formulation. Newtonian mechanics is relatively true: it correctly describes a certain range of phenomena but is superseded by relativity and quantum mechanics at extreme scales. Yet the relative truth it contains is not abolished — it is incorporated into a broader understanding.
The decisive test of any theory is practice. If our ideas correctly reflect objective reality, then action based on those ideas will succeed. The entire history of science, technology, and industry confirms the materialist theory of knowledge: we can know the world, and we prove this knowledge through transforming it. Practice is both the basis and the criterion of knowledge.
“The standpoint of life, of practice, should be first and fundamental in the theory of knowledge. And it inevitably leads to materialism, brushing aside the endless fabrications of professorial scholasticism.”— V. I. Lenin, Materialism and Empirio-Criticism, Ch. III
Lenin attacks the relativists and agnostics who use the relativity of knowledge to deny objective truth altogether. Yes, our knowledge is always relative, always approximate. But this does not mean there is no objective reality being approximated. The development of science is an asymptotic approach to absolute truth through an infinite succession of relative truths. To deny this is to open the door to every form of obscurantism — including religion.
Lenin demonstrates that empirio-criticism, far from being a neutral or scientific philosophy, is enthusiastically embraced by openly idealist and religious philosophers. The immanentists (Schuppe, Leclair, Rehmke), the pragmatists (William James), and various spiritualist thinkers all recognise Mach and Avenarius as allies — because the denial of objective reality outside consciousness is precisely the foundation upon which idealism and religion rest.
This is the chapter where Lenin develops the concept of partiinost (partisanship or party-mindedness) in philosophy. Philosophy is not a neutral academic discipline. It is a battleground between materialism and idealism, and these philosophical camps correspond, in the final analysis, to class interests. Materialism serves the interests of the progressive class — the proletariat — because it provides the scientific worldview necessary for understanding and transforming reality. Idealism, in all its forms, serves reaction — because it denies the knowability and transformability of the material world.
“Recent philosophy is as partisan as was philosophy two thousand years ago. The contending parties are essentially... materialism and idealism. The latter is merely a subtle, refined form of fideism, which stands fully armed, commands vast organisations and steadily continues to exercise influence on the masses, turning to its own advantage the slightest vacillation in philosophical thought.”— V. I. Lenin, Materialism and Empirio-Criticism, Ch. IV
This is one of the most forward-looking chapters of the book. At the turn of the twentieth century, physics was undergoing a revolution: the discovery of radioactivity, the electron, X-rays, and the beginnings of quantum theory were shattering the old mechanical picture of nature. Some physicists and philosophers concluded from these discoveries that “matter has disappeared” — that atoms were not solid, indivisible particles but consisted of electric charges, energy, and mathematical structures.
Lenin argues that what has disappeared is not matter but the old conception of matter. The electron is just as real, just as material, as the atom. The fact that our understanding of the structure of matter has deepened does not mean that matter itself has vanished. The confusion arises from identifying matter with a particular physical model, rather than with the philosophical category of objective reality.
The discovery that atoms consist of electrons and nuclei deepened our knowledge of what matter is. It did not prove that matter is “really” mind, consciousness, or energy in some non-material sense. Every new level of physical structure discovered — atoms, nuclei, quarks, fields — is still matter, still objective reality.
Lenin identified a “crisis of modern physics” rooted not in physics itself but in the idealist philosophical conclusions drawn from it. Physicists who lacked materialist training were drawn into idealism by the collapse of the mechanical model. The solution was not to abandon materialism but to develop dialectical materialism — a materialism capable of absorbing the revolution in physics.
The revolution in physics confirmed the dialectical materialist understanding of nature: matter is inexhaustible, knowledge develops through the resolution of contradictions, and every scientific theory is both a reflection of objective truth and a historically limited approximation. Dialectics is not imposed on nature — it is abstracted from nature.
“The ‘essence’ of things, or ‘substance,’ is also relative; it expresses only the degree of profundity of man’s knowledge of objects; and while yesterday the profundity of this knowledge did not go beyond the atom, and today does not go beyond the electron and ether, dialectical materialism insists on the temporary, relative, approximate character of all these milestones in the knowledge of nature gained by the progressing science of man. The electron is as inexhaustible as the atom, nature is infinite.”— V. I. Lenin, Materialism and Empirio-Criticism, Ch. V
This passage has been spectacularly confirmed by the subsequent history of physics. The electron turned out to have spin, magnetic moment, wave-particle duality, and quantum field-theoretic structure. The atom contained not just electrons and nuclei but protons, neutrons, quarks, gluons, and the entire apparatus of the Standard Model. Matter is indeed “inexhaustible” — every level of structure opens onto deeper levels.
The final chapter extends the critique to the social sciences. Just as empirio-criticism denies objective reality in natural science, it also undermines historical materialism — the materialist understanding of history. If there is no objective reality, then there can be no objective laws of social development, no scientific basis for understanding class struggle, no scientific foundation for revolutionary strategy.
Lenin shows that Bogdanov’s attempt to replace historical materialism with his own “universal organisational science” (later developed as “tektology”) was a retreat from the class-based, materialist analysis of society. Social being determines social consciousness — this fundamental thesis of Marxism requires the acceptance of objective reality, of material conditions existing independently of how people think about them.
The chapter also contains Lenin’s critique of the attempts to introduce “symbols,” “hieroglyphs,” and other intermediaries between consciousness and reality. Against all such theories, Lenin insists: our ideas are not symbols of reality but reflections of reality. The difference is decisive. A symbol has an arbitrary relationship to what it symbolises; a reflection has a necessary, causal relationship to what it reflects.
Matter is not a specific physical substance but a philosophical category denoting everything that exists independently of consciousness. It includes atoms, fields, spacetime, energy — anything that is objectively real. No particular physical theory can exhaust the concept of matter, because matter is inexhaustible. This definition immunises materialism against any “crisis” in physics: however our physical theories change, the materialist thesis — that objective reality exists independently of the mind — remains unshaken.
Human consciousness reflects objective reality. Sensations, perceptions, and concepts are images — not perfect copies, but increasingly accurate approximations — of things as they actually exist. Knowledge is not a construction of the mind from its own resources but a reflection of the external world, tested and refined through practice. This is the foundation of all science: the world is knowable, and our knowledge, though always incomplete, is objectively valid to the extent that it corresponds to reality.
Human knowledge is composed of relative truths — historically conditioned, approximate formulations — which contain grains of absolute truth. The sum of relative truths constitutes absolute truth. Science progresses not by replacing truth with truth, but by deepening and extending our grasp of objective reality. To deny absolute truth is to deny that science advances; to deny relative truth is to deny that science develops. Dialectical materialism holds both in unity.
There is no neutral philosophy. Every philosophical position serves either materialism or idealism, and these philosophical tendencies correspond to definite class interests. The proletariat needs materialism because it needs to understand the world as it really is in order to change it. The bourgeoisie gravitates toward idealism because idealism obscures the real relations of exploitation and domination. To be a consistent materialist is to take the side of the working class; to retreat into idealism — however “refined” or “scientific” — is to serve reaction.
Matter is infinite in depth. Every level of physical structure — molecules, atoms, nuclei, quarks — opens onto further levels. There is no “ultimate building block,” no final foundation at which analysis terminates. This is a dialectical understanding: nature has no bottom. It follows that scientific knowledge can never be complete, but it also follows that there is always more to discover — that the advance of knowledge is unlimited.
The ultimate test of theory is practice — experiment, production, social activity. If a theory correctly reflects reality, actions based on it will succeed. This principle unites theory and practice, thought and action. It is the foundation of the Marxist-Leninist insistence that philosophy must not merely interpret the world but guide its transformation.
The single most important passage in the entire book — and one of the most important definitions in all of Marxist philosophy — deserves to be quoted in full and studied with care:
“Matter is a philosophical category denoting the objective reality which is given to man by his sensations, which is copied, photographed and reflected by our sensations, while existing independently of them.”— V. I. Lenin, Materialism and Empirio-Criticism, Chapter II, Section 4
Every clause is load-bearing:
Matter is not identical with any particular physical theory of what matter is made of. It is a category of thought — the most general concept denoting what exists objectively. Atoms, fields, particles, spacetime — these are physical concepts that change with the development of science. The philosophical category of matter encompasses them all.
Matter is what exists independently of any subject, any observer, any consciousness. This is the essence of materialism: reality is not constituted by observation, perception, or thought. It is there whether anyone perceives it or not.
We know matter through our senses. Materialism does not deny the role of sensation in knowledge; it insists that sensation is a connection to reality, not a barrier against it. Our senses are evolved instruments for detecting the objective world — imperfect, limited, but genuinely informative.
Our sensations and ideas are images of real things. Not arbitrary symbols, not constructions, not conventions — but reflections of what actually exists. The metaphors of copying and photographing emphasise the causal, correspondence relationship between reality and thought.
The material world does not depend on consciousness. It existed before there were any conscious beings, and it will continue to exist after them. Consciousness is a late, local, and transient product of material development — not the ground of being.
Lenin insists throughout the book that the fundamental question of philosophy is the question of the relationship between matter and consciousness, between being and thinking. Every philosopher, every philosophical system, must answer this question — and the answer places them in one of two camps:
Matter is primary; consciousness is secondary. The world exists objectively, independently of the mind. Consciousness is a product of matter — specifically, of the brain. Knowledge is the reflection of objective reality in human consciousness. Science is possible because nature is real and knowable. This is the philosophy of the working class.
Consciousness is primary; matter is secondary (or derivative, or unknowable). The world is either a product of mind, a construction of experience, or something whose real nature is forever hidden from us. In all its forms — subjective idealism, objective idealism, agnosticism, positivism, phenomenology, empirio-criticism — idealism denies the independent existence and knowability of the material world. This serves reaction.
Every attempt to find a “third way” — to stand “above” the dispute, to combine materialism and idealism, to declare the question outdated — is, Lenin shows, a disguised form of idealism. Mach’s “elements,” Avenarius’s “experience,” Bogdanov’s “social organisation of experience” — all claim to transcend the opposition of matter and mind, and all, under analysis, prove to be idealism in a new costume.
A major target of the book is agnosticism — the position that the world may exist but we can never know it “as it really is.” This was the position of Kant (things-in-themselves are unknowable), of Hume (we can only know our impressions), and of the entire positivist tradition that followed them.
Lenin demolishes agnosticism with a simple but devastating argument: practice refutes it. When we build bridges using the laws of mechanics, and the bridges stand; when we synthesise chemical compounds predicted by theory, and they behave as predicted; when we navigate spacecraft using the equations of physics, and they arrive at their targets — we demonstrate that our knowledge of the world is not mere subjective impression but objective truth. The agnostic has no answer to the argument from practice.
“Life and practice have long ago decided this question... The success of practice proves the correspondence of our ideas with the objective nature of the things we perceive.”— V. I. Lenin, Materialism and Empirio-Criticism, Ch. II
The philosophical tendencies Lenin fought in 1908 have returned with a vengeance in the form of postmodernism, poststructuralism, and various forms of social constructivism in contemporary academia. The claim that there are no objective truths, only “narratives”; that science is merely a “social construction”; that reality is “constituted by discourse” — these are the direct descendants of the Machist position that Lenin demolished. They serve the same function: by denying the objectivity of knowledge, they undermine the scientific basis for understanding exploitation, class struggle, and the laws of social development.
The contemporary university is saturated with idealism. Phenomenology, hermeneutics, pragmatism, and analytic philosophy all share, in different ways, the Machist reluctance to affirm the independent existence of objective reality. In the social sciences, “interpretivism” and “constructivism” have largely displaced materialist analysis. In philosophy of mind, various forms of idealism — from property dualism to panpsychism — are presented as respectable alternatives to materialism. Lenin’s book remains the sharpest weapon against all of these positions.
When political discourse is dominated by the idea that “everyone has their own truth,” that objective analysis is impossible, that all positions are equally valid — this is empirio-criticism in political form. It serves the ruling class perfectly: if there is no objective truth about exploitation, about class, about imperialism, then there is no basis for revolutionary action. Lenin’s insistence on objective reality and objective truth is the philosophical foundation of revolutionary politics.
This site holds that everything is physics — that consciousness is computation, that there is no room for idealism, dualism, or mysticism of any kind. Lenin’s Materialism and Empirio-Criticism is the philosophical charter of this position. There is objective reality; it is material; consciousness is a product of the organisation of matter; knowledge is the reflection of reality in consciousness; and practice is the criterion of truth. No concessions to idealism. No “third way.” No compromise with obscurantism.
As Lenin wrote: the materialist position must be defended partisanly — with full awareness that philosophical neutrality is an illusion and that every retreat from materialism is a service to the enemies of the working class.
“The recognition of objective truth is characteristic of every materialist theory in general. The peculiarity of Marxism is that it combines the full materialist recognition of objective truth with the recognition that all our knowledge is relative, developing, moving closer to objective truth.”— V. I. Lenin, Materialism and Empirio-Criticism
“To regard our sensations as images of the external world, to recognise objective truth, to hold the materialist theory of knowledge — these are all one and the same thing.”— V. I. Lenin, Materialism and Empirio-Criticism
“The materialist elimination of the ‘dualism of mind and body’ (i.e., materialist monism) consists in the assertion that the mind does not exist independently of the body, that mind is secondary, a function of the brain, a reflection of the external world.”— V. I. Lenin, Materialism and Empirio-Criticism
“Natural science positively asserts that the earth once existed in such a state that no man or any other living creature existed or could have existed on it. Organic matter is a later phenomenon, the fruit of a long evolution... Matter is primary, and thought, consciousness, sensation are products of a very high development. Such is the materialist theory of knowledge, to which natural science instinctively subscribes.”— V. I. Lenin, Materialism and Empirio-Criticism
“Intelligent idealism is closer to intelligent materialism than stupid materialism.”— V. I. Lenin, quoting Hegel approvingly in Philosophical Notebooks
Why does Lenin insist that matter is a philosophical category rather than a physical one? What would happen to materialism if matter were identified with a specific physical theory?
Why did philosophical revisionism emerge in the RSDLP specifically after 1905? What is the connection between political defeat and retreat into idealism?
Why does Lenin argue there can be no “third way” between materialism and idealism? Is this a simplification, or does it reflect the genuine logic of the fundamental question of philosophy?
How did Lenin’s analysis of the “crisis in physics” anticipate later developments in quantum mechanics and particle physics? Has the subsequent history of science confirmed or refuted his position?
In what ways do contemporary postmodernist claims about truth, reality, and knowledge repeat the errors of empirio-criticism? How would Lenin respond to the claim that “there are no grand narratives”?
Why is the defence of objective truth essential to revolutionary practice? What happens to the workers’ movement if it accepts that truth is merely relative, subjective, or socially constructed?