Friedrich Engels famously spent his working life in the shadow of Karl Marx, a position he now occupies for posterity, and one in which he willingly placed himself.footnote¹ Born in 1820 in the Rhineland town of Barmen, he left school a year before his Abitur on the say-so of his father and, as the eldest son, entered the family business. An autodidact, then, his encounter with Marx left him profoundly impressed by the systematic-philosophical brilliance of the young Hegelian, whom he hailed as a world thinker. By comparison, he himself was no more than, perhaps, a talent. Among the German philosophizing classes of the time, the type of speculative thinking at which Marx excelled was considered the highest form of scientific endeavour; Engels, who shared this outlook, may have seen his own contribution, grounded in positivism, as pedestrian by comparison. In the collaboration with Marx, he understood his role to be that of editor, reader, publisher, translator, publicist and hence also popularizer of Marxian (not Marxist-Engelsian) theory, making it comprehensible to the socialist movement for which it was intended. That the act of translation resulted at times in simplifications and reductive formulations was not only unavoidable but desirable, though the price to be paid for it was the still-lingering suspicion that Engels was incapable of greater complexity.

Yet Engels had genuinely remarkable achievements to his name—and not despite, but precisely because his temperament inclined him towards the actually existing world, to realities rather than abstractions. Alongside his extraordinarily wide-ranging scientific, literary, journalistic and political undertakings, Engels would become a successful industrial entrepreneur with many years of experience. This not only enabled him to finance the slow progression of Marx’s theoretical production, it also furnished him with an understanding of capitalism from within, unusual among its opponents. In his own way, Engels was more at home in the world than Marx, the philosophical political-economist—which helps to explain how he could emerge, while still very young, as one of the earliest empirical sociologists. Witness The Condition of the Working Class in England, with the subtitle ‘According to My Own Opinions and Authentic Sources’, composed during Engels’s two-year stay in Manchester as a 24-year-old trainee at the local branch of his family’s textile factory. Marx, whom Engels had sought out in Cologne in 1842 on his way to England, was deeply impressed by the book and declared that Engels had ‘reached the same conclusion’ as himself, but ‘by a different path’—namely, that of empirical research.

So began a lifelong friendship and joint endeavour, which later produced, among other things, the Communist Manifesto of 1848, a milestone in the history of social-scientific theory and full of textual traces from Engels’s book, as was the first volume of Capital, published two decades later. What we might call the worldliness of Engels’s thought and research, his experience and his way of life, is also manifest in his virtually encyclopaedic intellectual output, driven by a hunger for facts that constantly sought out new themes, devouring entire libraries in his quest for the latest developments in knowledge. As an independent scholar he investigated the evolution of humankind, the historical anthropology of work, the origins of the family, early Christianity and German history, in particular the Peasant Wars, as well as taking on the emerging natural sciences in his Dialectics of Nature. While Marx could display a misanthropic streak, to put it mildly, the immediacy of Engels’s access to the world was undoubtedly one reason why he was the more politically active of the two. For the most part it was he who maintained contact with the international socialist movements of the time; it must have helped that he could apparently speak twelve languages fluently and could get by in twenty more.

I am nowhere near qualified to summarize the totality of Engels’s scholarly output. With him, as with other great thinkers, one can return to his work again and again and always discover something new. As a macro-sociologist, with an interest in the driving forces that shape the development of complex contemporary societies, I have been struck by the extent to which Engels complemented the materialist conception of history, worked out (with his help) by Marx as a critique of nineteenth-century political economy, with something like a theory of the state and politics. While Engels himself understood his contribution to be a mere supplement to Marx’s theory of historical materialism, I will argue that Engels can be considered the founder of an independent branch of materialist social theory, which contributed a much-needed expanded understanding of politics and the state.

What do I mean by ‘something like a theory’? First, as far as the ‘big picture’ was concerned, Engels always relied on Marx’s all-encompassing thought-system—partly because he trusted Marx for its development, but partly also, perhaps, by reason of his temperament as a researcher, which expressed itself in an insatiable and pre-systematic thirst for facts; facts that proved ever more resistant to systematization, the more of them he absorbed. Among the themes that attracted Engels’s sustained attention was the development of the armed forces and the wars that accompanied the simultaneous rise of capitalism and the modern nation-state.footnote² The connection of war and militarization to the political economy of the time, and to its future revolutionary overthrow, was far from clear, in part because of the elements of unpredictability already emphasized by Clausewitz—the contingencies and effects of ‘relative autonomy’ generated by the fog of war; the role of arms as, so to speak, a generator of historical accidents. Engels trained himself to become one of the leading military theorists of the time, a quirk that earned him the nickname of ‘the General’. Later he would be considered a major authority on these matters, and not only for socialist military strategists like Lenin, Trotsky and Mao Zedong; later still, an embarrassment for the postwar socialists-turned-pacifists unwilling to recognize the strategic role of force in politics. His contribution in this field was due in part, I would argue, to a particular affinity between the nature of modern warfare in the context of capitalist development and Engels’s readiness for undogmatic observation, which enabled him to lay the groundwork, at least, for a much-needed state-theoretical supplement to the political economy developed by Marx and himself.

It was not that Marx was uninterested in the wars of his time. For him, too, as a key passage in Capital put it, ‘Force is the midwife of every old society pregnant with a new one.’footnote³ At least until the 1880s, both Marx and Engels expected to see the end of capitalism in their own lifetimes, imagining peaceful transitions to be the exception. Where Engels had the advantage over Marx was in his practical experience, as a volunteer in the Prussian Artillery in Berlin 1841–42, as a participant in the 1849 Elberfeld uprising for the adoption of the Frankfurt Constitution, and in the swiftly repressed anti-Prussian rebellion of the Baden-Palatinate Army and the Baden Volkswehr—a painful defeat that remained with him for the rest of his life. Marx undoubtedly grasped the importance of this practice in military affairs and encouraged Engels to author a chapter on military history in the first volume of Capital. Engels agreed but, uncharacteristically, never delivered—an indication, perhaps, that his empirical material resisted subsumption into the commodity-fetish system of Marx’s political economy.

This was not because the ‘materialist conception of history’ was economically determinist and therefore apolitical, as some might claim today. It’s true that all the great social-scientific theories of the nineteenth century inclined towards determinist, even teleological, formulations, if only because they aimed to be ranked alongside the rising natural sciences. To the extent that these tendencies could be found in Marx’s and Engels’s work—and both thought that the path of history led ultimately in the direction of socialism—they were in good company. On the other hand, they differed from their contemporaries in that they were not only theorists of capitalist society but also practitioners of organized proletarian revolution; as such, they had to deploy the rhetoric of confidence in ultimate victory that is indispensable to a political movement but cannot always be reconciled with theory. Recall, too, that they both spent a good deal of time founding international workers’ organizations and advising national ones, interrupting their more scholarly endeavours again and again to do so. Had their theory boiled down to the claim that progress towards socialism would occur of its own accord, they could have spared themselves the effort. In fact, much of their attention from 1849 onwards was focused on political and military events, resulting in numerous journalistic and theoretical analyses. Once studies such as The Eighteenth Brumaire, The Civil War in France, and the long series of newspaper articles on the Crimean War and American Civil War are taken into account, it’s clear that historical materialism grants historical agency a far larger and more systematically prominent place than most academic social science, of that time or since.