We do not intend to go into this long-standing debate. What is significant at the moment is the assertion that in Marx’s ‘mature’ writings, not only the concept but also the term ‘praxis’, could nowhere be found. It is thus crucial at this juncture to prove that even in his later works, particularly in the Capital, praxis still plays a crucial role.
Richard Bernstein identifies three fashionable accusations hurled at the Capital. Firstly, Marx has here rejected his early philosophical musings particularly on ‘praxis’, ‘alienation’ and ‘species-being’. Secondly, he has transformed his language into predominantly ‘economic’ categories. Lastly, Capital projects a human being as one who is ‘swept along by the web of impersonal forces’ over which s/he has no control but to which s/he can only resign her/himself.
Bernstein contends that all of them are misleading. It might be true that Capital deals with seemingly abstract and impersonal economic categories as profit, surplus-value, wages and profit. But Marx’s intention there was to demystify them and to unearth their true real worth – they are in effect not independent realities but materialized expression of human labor, that is, crystallized forms of ‘social praxis’.
As Marx scientifically unfolds the workings of alienation in capitalist society through these categories, he also intends to state that they are not permanent and eternal features of the historical process. Since capitalism is riddled with contradictions, it is in fact destined to perish.
What emerges from Marx’s study in Capital is “not a sanctification or reification of economic laws, but the very opposite – a demonstration of the mutability of all so-called economic laws, the ways in which they arise, the internal dynamic contradictions they harbor, and the ways in which they pass away.”
One way to strengthen the above assertion is to examine Marx’s concept of ‘labor-power’. Bernstein suggests that ‘praxis’ serves as the key to understanding Capital’s key notion of value as crystallized in ‘labor value’.
It is oftentimes thought that values are natural, physical properties of things. Commodities are capable of being exchanged because they are said to be ‘valuable as such’. In Marx’s view, this is another inversion. Values do not inhere in things. Products become ‘commodities’ – that is, exchangeable – because there is a network of social relations which makes this possible.
In an exchange economy, when we trade the products of our own labor for money, we accept the fact that our human qualities somehow inhere in those commodities. In other words, our human labor has been reified and the commodities which are engendered therefrom could take on life of their own. The market then becomes a relationship of commodities, not of persons. ‘Commodity fetishism’, therefore, is the inability to see these exchangeable products as they really are, that is, as products of human labor. This is a dynamic even of barter economies.
But what capitalism does, in its division of society into capital-owner and wage-earners, is to aggravate the situation. Here, human labor itself becomes reified, that is, human subjects, because they have nothing else but their own labor-power, are compelled to sell themselves on the labor market where value is dictated by the now all-powerful commodities. That the human being, instead of wielding power over his own products, is enslaved by them – constitutes the foundation of all other forms of human alienation Marx has dissected so far (e.g., religious, political, etc.).
The intricate analysis in Capital of how this alienation takes on its concrete realization in the form of money, capital, surplus-value, profit, interest, etc. is Marx’s way of unmasking these seemingly powerful realities which have projected themselves as impersonal and determinative. He intends to show that these are not immutable laws after all.
In other words, he contends “that while they appear to the participants in a capitalist society as impersonal entities and forces, they are in reality – when demystified from their reified and fetishistic appearances – various forms of social praxis or social labor.”
Furthermore, the fundamental alienation present in the capitalist system bears out contradictions, which as they accumulate, also undermine the system itself. For Marx, the end of history – a consistent vision from his early writings to the Capital – is still that of
a free and “socialized man, the associated producers, rationally regulating their interchange with Nature, bringing it under common control, instead of being ruled by it as by the blind forces of Nature; and achieving this with the least expenditure of energy under conditions most favorable to, and worthy, of their human nature.”
 Here, we are indebted to R. Bernstein, Praxis and Action, 55-66.
 R. Bernstein, Praxis and Action, 58.
 Marx states: “A commodity therefore is a mysterious thing, simply because in it the social character of men’s labour appears to them as an objective character stamped upon the product of their labour; because the relation of producers to the sum total of their own labour is presented to them as social relation, existing not between themselves but between the products of their labour. This is the reason why the products of labour become commodities, social things whose qualities are at the same time perceptible and imperceptible by the senses… The existence of things qua commodities, and the value-relation between the products of labour which stamps them as commodities, have absolutely no relation to their physical properties and with the material relations arising therefrom. Here it is a particular relation between men that assumes, in their eyes, the imaginary form of a relation between things. To find an analogy we must have recourse to the mist-enveloped regions of the religious world, where the productions of the human brain appear as independent beings endowed with life, and entering into relation both with one another and with the human race.” K. Marx, Capital, I, in K. Marx and F. Engels, Collected Works, Vol. 35 (London: Lawrence & Wishart, 1996), 82-83.
 K. Marx, Capital I [see “The Fetishism of Commodities and the Secret Thereof”], in K. Marx and F. Engels, Collected Works, Vol. 35, 81-93.
 R. Bernstein, Praxis and Action, 61.
 In the Capital, Marx writes: “The life-process of society, which is based on the process of material production, does not strip of its metaphysical veil until it is treated as production by freely associated men, and is consciously regulated by them in accordance with a settled plan. This, however, demands for society a certain groundwork or a set of conditions of existence which in their turn are the spontaneous product of long and painful development.” K. Marx, Capital, vol. I, in K. Marx and F. Engels, Collected Works, Vol. 35 (London: Lawrence and Wishart, 1996), 90-91. The same vision pervades Marx’s early writings. “The human essence of nature exists only for social man; for only here does nature exist for him as a bond with other men, as his existence for others and their existence for him, as the vital element of human reality; only here does it exist as the basis of his own human existence… Society is therefore the perfected unity in essence of man with nature, the true resurrection of nature, the realized naturalism of man and the realized humanism of nature.” K. Marx, Economic and Philosophical Manuscripts, in idem, Early Writings, 349-50; “The standpoint of the old materialism is civil society; the standpoint of the new is human society; or social humanity.” K. Marx, Theses on Feuerbach [Thesis 10], in K. Marx and F. Engels, Collected Works, Vol. 5, 5.
 K. Marx, Capital, Vol. III, in K. Marx and F. Engels, Collected Works, vol. 37 (London: Lawrence and Wishart, 1998), 807 [italics mine].