[Originally published in Concilium: Christianity and socialism, edited by Johann-Baptist Metz and Jean-Pierre Jossua, 1977.]
The existence of social classes and class conflict is not only an irrefutable finding of Marxism but is acknowledged in papal teaching; Piux XI in Quadragesima Anno, for example, recognizes that ‘modem society, is constructed on the antagonism of class interests and hence on class conflict’. The destructive nature of capitalism is confirmed in the social encyclicals, which also approve the struggle of the working class for basic needs, justice and human dignity, and express solidarity with the exploited classes. There is always a warning against systematic class hatred, however, and against irreconcilable enmity in the political and economic struggle. This is where the criticism of Marxism-Leninism comes in.
The differences between both camps do not however begin with political practice based on class division, but in the definition of the very notion of class, and continue in the explanation of the cause of class division and the analysis of class warfare.
The decisive consequence of the understanding of the notion of class in Catholic social teaching is opposition to the necessity of class warfare as a systematic component of capitalism, and its reduction to a transient phenomenon resulting from class egotism and hence the moral decision of the individual; and also the supposition that this modified notion of class warfare is reconcilable with a conception of a common good which applies to all men equally as the essential basis of social reality. Then it is possible to conceive and promote reconciliation of the classes by common orientation to the common good, and by doing away with specific class interests.
Most of the objections raised against Marxist class theory (abstractness, over-simplification, distance from real life, anachronism) result from an inadequate understanding of the function and logical structure of this theory, but mainly from a lack of acquaintance with the ‘method of idealization and concretization of theoretical models’ used by Marx in Capital when establishing the fundamental categories and laws of the theory.  That has given rise to a false theoretical controversy, and has obscured the interaction of type of theory and basis of interest. This article is an attempt to correct this basis of discussion.
LOGICAL CHARACTERIZATION OF THE MARXIST THEORY OF CLASS AND CLASS WARFARE
The Marxist-Leninist theory of class and class conflict, a basic component of historical materialism, tries to answer the following questions: (a) into what classes is a society divided; (b) what is the cause of class division; (c) what relation do the social classes have to one another, and what influence do they have as a result on the course of history?
Class theory therefore neither enjoys the status of an arbitrary invention or one determined by interests, nor is it a tendentious refinement of existing contradictions, but represents the scientific discovery of decisive laws whose logical structure is to be shown. Marx himself said that he did not claim to have discovered the existence of classes in modern society nor conflict between them: ‘What I was the first to do, was (1) to show that the existence of classes is merely connected with specific phases in the historical development of production; (2) that class conflict necessarily leads to the dictatorship of the proletariat; (3) that this dictatorship itself is only the transition to the cancellation of all classes and to the classless society’. 
This statement affords four important insights;
(a) Classes and class struggle are not unchanging phenomena necessarily posited with human or social nature as such, but are themselves the products of an historical development which leads from the downfall of the classless tribal communities to capitalist class society.
(b) The most important characteristics for defining social classes are obtained by analysis of the method of production.
(c) Class warfare is not only a result but a means of ending class division and class rule.
(d) The main work of transition to the classless society is undertaken by the proletariat, since under capitalism it is the most fiercely exploited class.
The main findings of Marxist class theory, as worked out by Marx especially in the context of his analysis of capitalist society in Capital, are to be classed as an explanatory theoretical model. On the presupposition of a number of idealistic assumptions about the pure form of capitalism, Marx derives by logic structurally descriptive statements and laws which can be gradually reduced to concrete instances by application of the idealistic premisses to empirical data.
We can use the concept of class to see how this method works, and how successful it is, by moving from the abstract to the concrete in the establishment of fundamental categories.
In the first two volumes of Capital Marx presents a ‘pure form’ of the capitalist mode of production, which relies (among others) on the following idealistic assumptions:
(a) The capitalist entrepreneur is the owner of the entire surplus value produced; (b) the members of a social category are sufficiently alike. 
In Capital we can of course find many other similar assumptions which do not have to be raised here explicitly. Marx derives from them the following law: If the assumptions under (a) and (b) above are correct, then society is divided into industrial capitalists who appropriate the surplus value, but do not produce, and industrial proletarians, who produce it, and do not appropriate it, but have to sell their labour power as a commodity (the causal explanation of class division).
From such findings Marx establishes a model of the class structure of capitalist society in its pure form. Once we have the pure form, then by modifications of the idealistic premisses we can show by what laws the actual circumstances arise. Here we have, for example, to introduce the modified premiss that the industrial capitalist has to share the surplus value produced with the trading and financial capitalists.
The notion of class is developed in terms of industrial and commercial capitalists set against industrial and commercial workers. The more the premisses are modified by the addition of social parameters, the more refined our picture of class structure becomes. It is then clear that one’s relation to the means of production is a decisive but not the sole characteristic for the definition of social classes. The class structure of a societal structure naturally includes not only basic classes defined by the existing mode of production (capitalists and wage labourers), but ‘subsidiary’ classes and social strata (peasants, petit bourgeoisie, intellectuals).
Therefore historical materialism, contrary to the objections of bourgeois scientists, does not deny the complex character of social class relations, but only refuses to allow the definitive class structure to be lost in a swamp of second-level indices and secondary relations
Even though the further development of the model cannot be pursued here, the following can be: (a) the class concept obeys its own unique developmental logic which allows systematic refinement of its semantics; and (b) the existing theory can be modified and can grasp increasingly complex aspects of social reality by gradually increasing its own complexity. The level of the theory can be adapted to meet new demands for explanation.
As explanatory theory, the Marxist theory of class may be counted among the empircally nomothetic sciences. But its materialist approach, orientation to ideology-criticism and revolutionary solidarity, enable it to offer a theory and practice extending beyond this type.
There is a permanent structural link between classes and class struggle in regard to the form of a society: ‘Social classes do not exist a priori, as such, in such a way that they eventually engage in class struggle, which would allow the assumption that there were classes without class conflict. . . The analysis of classes, which includes conflict between classes as well as political and ideological circumstances, describes the objective positions taken up by agents within the societal division of labour: these positions are independent of the will of those agents . . . This structural determination of classes, which here appear only in the form of class conflict, must nevertheless be distinguished from the position of classes in the economy, which is the place where the historical individuality of a societal formation, in short the actual situation of the class struggle, is concentrated.’  That affords the major components of a definition:
(a) Class conflict is the direct reflection of the original antagonism of the mode of production (between capital and labour) on the level of social conditions.
(b) Class struggle does not concern only the economic structure, but from the start the political and ideological sector. Political contradictions and ideological controversies are not to be confused with economic positions, but are, exactly like economic exploitation, objective aspects of class rule.
(c) The structural definition of class conflict therefore makes it impossible to reduce it to mere confrontations of economic interests and individual decisions.
(d) Individual fractions of social classes do not necessarily behave in accordance with their structural nature. A typical example of this is the ‘worker aristocracy’ in industrial concerns which is dependent on wages but co-operates politically and ideologically with the bourgeois class position.
(e) Even a wholly ethically desirable solution to class conflict and a change of procedure in the class struggle remain illusionary as long as its causes are not removed.
Since class conflict has a polarized structure (that is, its components are mutually conditioned by opposition), it is essentially unstable; this gives rise to a dynamic process. This process occurs in one direction as forceful stablization of class division by the ruling class, and in another direction as the attempt of the oppressed class to end class division by eventually establishing a classless society. An ultimate end to class conflict can therefore only come about if progress is made to a higher form of society in which the causes of class division are removed.
THEORETICAL AND PRACTICAL ASPECTS OE THE CHALLENGE TO CATHOLIC SOCIAL TEACHING
Catholic social teaching, insofar as it claims to be a theological discipline, and appears in that form, must offer respectable solutions in the following problematic areas:
Catholic social teaching has to define its own scientific understanding and its position in theoretical scientific discourse. An important step in this direction would be a refinement of the logical form of its own propositions. Is Catholic social teaching really based on empirically substantial, analytically proven propositions regarding historical and social reality? Surely its premisses lay claim to descriptive content but are no more than normative judgments or wishful prescriptions (if not mere illusionary hypotheses) about reality. Catholic social teaching is far too often arrested at the stage of generalizations: commonplace assessments of phenomena that are only halfway to an explanation.
The questions I have asked not only demand a more scientifically responsible form of self-reflection, but a redefinition of contents. The form and method of data assembly also need rethinking. In this regard, the methodological relevance of political options also have to be rethought, and the basis of interest and practical orientation of Catholic social teaching require thorough investigation. Its frequent attempts to separate class conflict from the existence of classes put it into close theoretical and practical union with bourgeois social science, and are supported by capitalist organizations.
The theoretical level of the Marxist analysis of classes and class conflict forces Catholic social teaching to revise many of its suppositions about that theory, but above all to discard a journalistic and simplistic approach in regard to Marxism and to replace it with a form of meta-theoretical discourse conducted in accordance with testable rules. Notwithstanding objections to the contrary, Marxism is well acquainted with the distinction between truth and falsehood on the level of theory, but it examines a truth claim not in terms of a positivistic notion of the correspondence theory of truth, but in the context of a critical understanding of the relationship between theory and praxis.
Catholic social teaching must declare its own class standpoint, justify it, and if necessary revise it. That it does represent a class standpoint in theory and practice is especially clear from the following points—the initiators (conservative bishops and right-wing proponents of Catholic social teaching)  are almost always the same:
(a) A worldwide campaign is being conducted from Federal Germany against the theology of liberation; prominent members of the Adveniat organization are involved at an important level. In theory this is a hunt behind the screen of Catholic social teaching for latent Marxism in the thinking of many Latin American theologians. In fact an attempt is being made to split the Latin American Church.
(b) Anti-Communism is used as an emotional instrument by theoretical advisers to the magisterium and church organizations, and Catholic social teaching is cited as a justification for this, as if anti-Communism were an essential part of all that Jesus and his followers stand for. The position papers of the international organizations CAJ and MUARC were fiercely attacked by ideological centres in the Federal Republic calling in question their alleged use of Marxist analysis.
(c) An entire series of volumes has been devoted to an attack on the political left in church organizations and is an attempt to justify the campaign theoretically. Church bodies also advise leading Catholic businessmen and openly advance reactionary social theories. 
The right-wing representatives of Catholic social teaching show by this conduct how they themselves wage class warfare, and organize themselves in that struggle as an anti-revolutionary force. The circles to which I refer not only openly contradict the obvious solidarity of the papal encyclicals with the working class, but are contrary to the political commitment of many progressive Christians all over the world.
Translated by J. Maxwell
 Cf. A. Jasinska and L. Nowak, ‘Grundlagen Marxschen Klassentheorie. Fine Rekonstruktion’, in: J. Ritsert (ed.), Zur Wissenschaftslogik einer kritischen Soziologie (Frankfurt, 1976), pp. 175-213, esp. p. 179. I rely subsequently to a great extent on the results of this work.
 See K. Marx to J. Weydemeyer, in Marx-Engels, Werke, vol. 28, pp. 507 flf.
 See K. Marx, Das Kapital, vol. 1, Marx-Engels, Werke, vol. 23, pp. 590, 607, 669 f
 N. Poulantzas, Klassen im Kapitalismus heute (West Berlin, 1975), p. 14
 Cf. the colloquium of the study circle ‘Church and Liberation’ held from March 2 to 7 in Rome; among the participants were: Bishop Franz Hengsbach, Bishop Alfonso Lopez, Roger Vekemans, Anton Rauscher, Wilhelm Weber, E. Stehle. See the reports by KNA (no. 53 of 4 March 1976 and no. 54 of 5 March 1976).
 Cf. especially the two series Kirche and Gesellschaft, published by the Centre for Catholic Social Studies in Monchengladbach, and Katholische Soziallehre in Text und Kommentar, published by the Union of Catholic Entrepreneurs, the Catholic Employers Movement and the Kolpingwerk Deutscher Zentralverband.