As with the modern state, modern law belongs to the “superstructure” and is structurally rooted in the capitalist mode of production, i.e. the “base”. The theory of historical materialism, which is an application of dialectical materialism to social relations, accords superstructural status to law. In Marx’s words, “[t]he totality of these relations of production constitutes the economic structure of society, the real basis from which rises a legal and political superstructure, and to which correspond specific forms of social consciousness”. 
In many of his writings, Marx insists that the ideologies of law and the state are the products or reflections of the material conditions of the society. In reference to a penal code, for instance, he claims that
[t]his Code Napoléon, which I am holding in my hand, has not created modern bourgeois society. On the contrary, bourgeois society, which emerged in the eighteenth century and developed further in the nineteenth, merely finds its legal expression in this Code. As soon as it ceases to fit the social conditions, it becomes simply a bundle of paper. 
This statement clearly emphasises the point that law develops according to the material conditions of a given society. On this account, the history of law is associated with the history of modes and relations of production. The legal superstructure grows from and through these modes and relations of production. As Marx puts it, “[s]ociety does not rest on law. That is a phantasy of jurists. On the contrary law–in contrast to the arbitrariness of the separate individuum–must rest on society, must be an expression of society’s general interest and needs, as they emerge from a given material means of production.”  The superstructure comprises law, the state, religion, prevailing conceptions of morality, and so on–all of which correspond to definite types of social consciousness.
This is clearly a mechanical understanding of base-superstructure relations. As such, it has frequently been criticized as deterministic and reductionist. If the base determines the nature of the superstructure, including law, all aspects of the superstructure, including law, can be reduced to the base or derived from it. But the writings of Marx and Engels demonstrate that it is not possible to reduce all social relations, including those involving “superstructural” elements, to a single base. For instance, in a famous letter to Bloch, Engels clarifies that the various elements of the superstructure exercise influence upon the course of historical struggles and are in many cases preponderant in determining the course of the economy:
The economic situation is the basis, but the various elements of the superstructure–political forms of the class struggle and its results, to with constitutions established by the victorious class after a successful battle, etc., juridical forms, and even the reflexes of all these actual struggles in the brains of the participants, political, juristic, philosophical theories, religious views and their further development into systems of dogmas–also exercise their influence upon the course of the historical struggles and in many cases preponderate in determining their form. There is an interaction of all these elements in which, amid all the endless host of accidents (that is, of things and events whose inner interconnection is so remote or so impossible of proof that we can regard it as non-existent, as negligible), the economic movement finally asserts itself as necessary. Otherwise, the application of the theory to any period of history would be easier than the solution of a simple equation of the first degree. 
Marxism discloses the origin and nature of law and the state as resting upon the material conditions of social relations. As a result, it cannot be said that as an element of the superstructure, the law has no impact on politico-economic relations. Instead, law can–and does–influence politico-economic relations. Engels explains the dialectical relationship between the base and superstructure by reference to law in another letter, this one to Schmidt:
In a modern state, law must not only correspond to the general economic condition and be its expression, but must also be an internally coherent expression which does not, owing to internal conflicts, contradict itself. And in order to achieve this, the faithful reflection of economic conditions suffers increasingly. … The reflection of economic relations in the form of legal principles is likewise bound to be inverted: it goes on without the person who is acting being conscious of it. … The basis of the right of inheritance is an economic one, provided the level of development of the family is the same. It would, nevertheless, be difficult to prove, for instance, that the absolute liberty of the testator in England and the severe and very detailed restrictions imposed upon him in France are due to economic causes alone. But in their turn they exert a very considerable effect on the economic sphere, because they influence the distribution of property. 
The legal superstructure cannot always be the faithful reflection of the base, and it cannot maintain the “purity” of the base. Engels thus proposes an early form of what has since come to be known as the “relative autonomy” thesis, though he also argues that this does not compromise law’s role as a general expression of socio-economic conditions. Engels argues that while the ultimate determinants of social relations are economic in nature, it is obtuse to reduce all elements of the superstructure to this economic base. In his later writings, he tries to resolve the problem by approaching base-superstructure relations dialectically. In the same letter to Bloch, he insists that “Marx and I are ourselves partly to blame for the fact that the younger people sometimes lay more stress on the economic side that is due to it. We had to emphasise the main principle vis-à-vis out adversaries, who denied it.”  He explains how elements of the superstructure may influence the base to a certain degree. Cornforth clarifies this in the following terms:
More remotely connected with the economic basis and more directly related to the current institutional and political conflicts, there arise further ideological processes–religious, legal, philosophical, artistic and so on–and the institutions associated with them. … [T]he relation of “basis” and “superstructure” is essentially a dynamic not a static relation. 
Cornforth further maintains that “the ideas and institutions which are developed on the basis of the economy are not simply a ‘reflex’ or by-product–they are not simply passive consequences, but play an active role in relation to the economy”.  This is a further blow to the mechanical conception of base-superstructure relations.
Engels seeks to track the development of legal ideas while explaining how law reflects economic conditions. He believes that both private and public law are anchored in and reflective of economic conditions. He notes that with the emergence and consolidation of the capitalist mode of production, laws changed gradually, not abruptly, with existing feudal laws generally being preserved. Indeed, while the modes of production differed, the essential nature of private law as a body of rules recognizing and formalizing private property continued: ancient law, feudal law, and bourgeois law are all committed to the protection of private property. Laws do not change automatically when capitalist society comes into existence. In England the old feudal laws came to be given capitalist content. Hence the “legal ideas and codes of law arose, not as a direct product of economic conditions, but by process of working upon and adapting the already existing law, which belonged to a past epoch, into forms suitable for the new epoch.” 
In sum, the metaphysical understanding of the separation of base and superstructure leads to a distorted understanding of the Marxist theory of law. If dialectical materialism is applied to the base-superstructure theory, we discover that the legal superstructure is not isolated from but rather dialectically attached to the base. This begs the question of whether the superstructure can alter the base. Marx said that revolutions are not made by laws, and this generally holds true. However, a mode of production can indeed be modified through legal changes. International law, for instance, can be used to restructure basic economic relations. As Engels noted in his letter to Schmidt, the superstructure can modify and influence the base within certain limits.
 Karl Marx, “‘Preface’ to A Contribution to the Critique of Political Economy” , in Karl Marx, Later Political Writings, ed. Terrell Carver (Cambridge: Cambridge University Press, 1996) 158, at 159–60; also available (in different translation) at https://www.marxists.org/archive/marx/works/1859/critique-pol-economy/preface.htm.
 Karl Marx, “The Trial of the Rhenish District Committee of Democrats” , 231/232 Neue Rheinische Zeitung, available at https://www.marxists.org/archive/marx/works/1849/02/25.htm.
 Quoted in Andrei Y. Vyshinsky, The Law of the Soviet State, trans. Hugh W. Barb (New York: Macmillan, 1948), 37.
 F. Engels to J. Bloch [21 September 1890], available at https://www.marxists.org/archive/marx/works/1890/letters/90_09_21.htm
 F. Engels to C. Schmidt [27 October 1890], quoted in Maureen Cain and Alan Hunt (eds), Marx and Engels on Law (London: Academic Press, 1979), 57.
 Engels to Bloch.
 Maurice Cornforth, Dialectical Materialism: An Introduction, vol. 2 (New York: International Publishers, 1971), 86.
 Ibid., 87.
 Ibid., 93.
S. Anandha Krishna Raj is Assistant Professor of Law at Vellore Institute of Technology School of Law in Chennai.