Marx’s Critique of Capitalism: Surplus Value and Alienation

Why does someone who builds a house often struggle to afford one? Why do the people who stitch clothes, assemble phones, and harvest food frequently earn the least from what they create? Karl Marx spent much of his life trying to answer questions like these. His critique of capitalism is not just an attack on greedy individuals, but a systematic argument that the entire structure of capitalist production is built on a hidden form of exploitation. Two ideas sit at the centre of this argument: the theory of surplus value and the theory of alienation. Together, they explain both how capitalists make their profits and what this system does to the human beings caught inside it.

The foundation: labour as the source of value 🔗

To understand Marx’s critique, you first need to understand where he believed value comes from. Following the earlier economist David Ricardo, Marx adopted the labour theory of value, which holds that human labour is the true source of economic value in commodities. A chair, a loaf of bread, or a smartphone is valuable because human effort and time went into producing it. Raw materials and machines matter, but Marx argued that machines and materials only transfer value that already exists in them. Living human labour is the only thing that creates new value.

This distinction is crucial. Marx separated what he called constant capital, the value stored in raw materials and machinery, from variable capital, the value of the workers’ labour power, which he identified as the sole source of surplus value and therefore of profit. If labour is where value originates, then the question becomes: who gets to keep that value once it is created? Marx’s answer forms the heart of his critique.

The theory of surplus value 🔗

The theory of surplus value is, in Marx’s own estimation, his most important contribution to economic thought. It rests on a single, subtle distinction that changes how we see the entire wage system: the difference between labour and labour power.

Labour power as a commodity 🔗

Under capitalism, workers do not own the factories, tools, or land needed to produce goods. Having nothing to sell but their capacity to work, they sell this capacity, their labour power, to those who own the means of production. Marx was the first political economist to identify labour power itself as a commodity that can be bought and sold on the market like any other. Importantly, it is sold only for a fixed period of time. If it were sold permanently, the worker would not be a worker at all but a slave.

Like any commodity, labour power has a value. Marx argued this value equals the cost of keeping the worker alive and able to work, in other words, the cost of food, housing, clothing, and everything needed to reproduce the worker day after day and raise the next generation of workers. This is roughly what determines wages.

How surplus value is created 🔗

Here is where Marx’s insight becomes sharp. The capitalist pays the worker the value of their labour power, the wage. But what the capitalist actually uses is the worker’s labour, and labour has the special power to create more value than it costs to maintain. The value a worker produces in a working day is greater than the value of the wages they receive.

Consider a simplified example. Suppose a worker needs only four hours of work to produce enough value to cover their own wages. But the working day lasts eight hours. During those first four hours, the worker is essentially producing their own pay, what Marx called necessary labour. During the remaining four hours, the worker continues producing value, but this value is kept by the capitalist. Marx called this surplus labour, and the value it creates is surplus value. As one summary of the theory puts it, if a worker generates a certain amount of value in a day but is paid only a fraction of it, the remainder is surplus value appropriated by the capitalist.

This is the origin of profit. The capitalist does not profit by cheating in the marketplace or by buying cheap and selling dear. Profit comes from the unpaid labour of workers during the production process itself. The wage contract appears fair on the surface, value seems to be exchanged for value, but beneath this appearance lies a fundamentally unequal exchange. This is what Marx meant when he said capitalism is exploitative: not as a moral insult, but as a description of how the system extracts unpaid labour.

Absolute and relative surplus value 🔗

Marx identified two main ways capitalists increase the surplus value they extract. The first is absolute surplus value, achieved by lengthening the working day so that more surplus labour is squeezed out on top of the necessary labour. The second is relative surplus value, achieved by increasing productivity, often through new machinery, so that the worker covers the cost of their own wages in less time, leaving a larger share of the day as surplus labour. The historic struggles over the length of the working day, and later over automation, are not side issues in Marx’s account. They are direct battles over how much surplus value capital can extract.

The theory of alienation 🔗

If surplus value explains the economic mechanism of exploitation, the theory of alienation explains its human cost. Marx developed this idea most fully in his early work, the Economic and Philosophic Manuscripts of 1844. Influenced by Ludwig Feuerbach, Marx argued that alienation was not some vague spiritual condition but a concrete, historical consequence of the capitalist system, and therefore something that could be overcome by changing that system.

Alienation, in simple terms, refers to the estrangement and disconnection workers feel under capitalism, from what they make, from the act of making it, from themselves, and from one another. Marx identified four distinct forms of alienation.

Alienation from the product of labour 🔗

The first form is the worker’s estrangement from what they produce. Under capitalism, the worker does not own the products they make; these belong to the capitalist and are sold for profit. The product, which is the result of the worker’s own effort, confronts the worker as something alien, a power independent of the producer. The more the worker produces, the more wealth flows to the capitalist, and the more the worker’s own creation stands over and against them as a hostile force. A worker on an assembly line may produce hundreds of items they could never afford to buy.

Alienation from the act of production 🔗

The second form concerns the work process itself. Production under capitalism is typically repetitive, mechanical, and dictated by someone else. The worker does not decide what to make, how to make it, or at what pace. As one analysis describes it, the design and development of production rest not in the hands of the worker but in the decisions of the capitalists who own the means of production. Work becomes forced and external, undertaken only as a means of survival rather than as a fulfilling expression of one’s abilities. The worker feels at home only in leisure time and feels like a stranger during the hours of work.

Alienation from species-being 🔗

The third and most philosophical form is alienation from what Marx called species-being (Gattungswesen), our distinctly human essence. For Marx, what separates humans from animals is the ability to engage in free, conscious, creative activity, to shape the world deliberately and find ourselves reflected in what we create. Under capitalism, this capacity is reduced to a mere means of survival. Labour, which should be the highest expression of human nature, becomes simply a way to earn enough to keep living. The worker is cut off from their own humanity.

Alienation from fellow workers 🔗

The fourth form is estrangement between people. Capitalism pits workers against one another through competition for jobs and wages, and it turns human relationships into market relationships. As Marx put it, within the relationship of estranged labour, each person comes to view others through the standard they occupy as workers. Cooperation gives way to rivalry, and genuine community is replaced by self-interested calculation.

How the two theories connect 🔗

Surplus value and alienation are not separate complaints; they are two faces of the same critique. Surplus value describes the objective, economic relationship: the extraction of unpaid labour that produces profit. Alienation describes the subjective, human experience of being inside that relationship: the loss of control, meaning, and connection. The very mechanism that allows capitalists to profit, the worker selling their labour power and surrendering control over the production process, is also what produces the worker’s estrangement.

Commodity fetishism and the hiding of exploitation 🔗

Marx added a further layer in Das Kapital with the idea of commodity fetishism. In a market economy, goods are exchanged based on their prices, and the social relationships of exploitation behind them become invisible. We see a finished smartphone as a sleek, desirable object, but we do not see the mining of minerals, the assembly under tight quotas, or the global chains of labour that produced it. The relations between people appear to us as relations between things. This is one reason exploitation under capitalism is so hard to perceive: the system naturally disguises it.

Systemic coercion, not individual villainy 🔗

A common misunderstanding is to read Marx as condemning individual capitalists as evil. His argument is structural. The wage relationship looks voluntary, a worker freely agrees to a job, but Marx pointed out that workers who own no means of production have little real choice. They must sell their labour power or starve. Because workers spend their wages on the necessities of life, they are forced to return to work the next day and repeat the cycle. This is the systemic coercion built into capitalism: the freedom of the market masks an underlying compulsion.

For Marx, this analysis also pointed toward conflict. Because the interests of the capitalist class (maximising surplus value) and the working class (receiving the full value of their labour) are fundamentally opposed, capitalism generates an ongoing class struggle. The same relations of production that create profit also lay the material conditions for workers to recognise their shared situation and organise against it.

Why these ideas still matter 🔗

Whether or not one accepts Marx’s conclusions, his concepts remain powerful analytical tools. Debates about gig economy workers, low wages in global supply chains, automation replacing jobs, and burnout in repetitive work all echo the questions Marx raised. The theory of surplus value asks who really captures the wealth that labour creates. The theory of alienation asks what kind of human experience our work produces. These questions are as relevant in an age of warehouse fulfilment centres and app-based labour as they were in the factories of the nineteenth century.

What do you think? If the value workers create exceeds what they are paid, is the gap best understood as exploitation, a fair return for those who provide capital and risk, or something in between? And in your own experience of work or study, have you ever felt the kind of disconnection Marx described as alienation?

References

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