"The philosophers so far have only interpreted the world: the point is to change it." Marxist history has developed along parallel lines, corresponding to the two halves of Marx's famous thesis. Most intellectuals who became Marxists from the 1880s on, including historians, did so because they wanted to change the world in association with the labour and socialist movements. This motivation remained strong until the 1970s, before a massive political and ideological reaction against Marxism began. Its main effect has been to destroy the belief that the success of a particular way of organising human societies can be predicted and assisted by historical analysis.
Meanwhile what of "interpreting the world"? Here the story is about a double movement. This challenged the positivist belief that the objective structure of reality was self-explanatory - all that was needed was to apply the methodology of science to it. At the same time, it was a movement to bring history closer to the social sciences, and turn it into part of a generalising discipline capable of explaining the transformations of human society. History was to be about "asking the big 'why' questions".
Marxism contributed to both these movements - though it has been mistakenly attacked for an alleged blind objectivism. But the most familiar impact of Marxist ideas, the stress on economic and social factors, was not specifically Marxist; it was part of a general historiographical movement which was to reach its peak in the 1950s and 1960s.
The historical interests of most Marxist historians were not so much in the base - the economic infrastructure - as in the relations of base and superstructure. This socio-economic current was wider than Marxism. These historical modernisers asked the same questions and saw themselves as engaged in the same intellectual battles, whether inspired by human geography, Weberian sociology or the Marxism of the communist historians who became carriers of historical modernisation in Britain.
They all saw each other as allies against historiographical conservatism, even when they represented mutually hostile positions. This front of progress advanced from the second world war to the 1970s. There followed a transition from quantitative to qualitative studies, from macro- to micro-history, from structural analysis to narrative, from the social to the cultural.
Since that time the modernising coalition has been on the defensive. And yet the need to insist on what Marxism can bring to historiography is greater than for a long time. History needs to be defended against those who deny its capacity to help us understand the world, and because new developments in the sciences have transformed the historiographical agenda.
Methodologically, the major negative development has been the construction of a set of barriers between what happened in history and our capacity to observe and understand it. It is denied that there is any reality that is objectively there and not constructed by the observer for different and changing purposes. It is claimed that we can never penetrate beyond the limitations of language.
Meanwhile, less theoretically minded historians argue that the course of the past is too contingent for causal explanation, because the options in history are endless. Pretty well anything could happen or might have happened. Implicitly, these are arguments against any science. I won't bother about the more trivial attempts to return to the past: the attempt to hand back its course to high political or military decision-makers, or to the omnipotence of ideas or "values", or to reduce historical scholarship to the search for empathy with the past.
The major immediate political danger to historiography today is "anti-universalism" or "my truth is as valid as yours, whatever the evidence". This appeals to various forms of identity group history, for which the central issue of history is not what happened, but how it concerns the members of a particular group. What is important to this kind of history is not rational explanation but "meaning", not what happened but what members of a collective group defining itself against outsiders - religious, ethnic, national, by gender, or lifestyle - feel about it.
The past 30 years have been a golden age for the mass invention of emotionally skewed historical untruths and myths. Some of them are a public danger: I am thinking of countries like India under the BJP, the US, Silvio Berlusconi's Italy, not to mention many of the new nationalisms, with or without fundamentalist religious reinforcement.
This produces endless claptrap on the fringes of nationalist, feminist, gay, black and other in-group histories, but it has also stimulated interesting new historical developments in cultural studies, such as what has been called the "memory boom" in history.
It is time to re-establish the coalition of those who believe in history as a rational inquiry into the course of human transformations, against those who distort history for political purposes - and more generally, against relativists and postmodernists who deny this possibility. Since some of the latter see themselves as being on the left, this may split historians in politically unexpected ways.
The Marxist approach is a necessary component of this reconstruction of the front of reason. While postmodernists have denied the possibility of historical understanding, developments in the natural sciences have put an evolutionary history of humanity firmly back on the agenda.
Firstly, DNA analysis has established a firmer chronology of the spread of the species from its original African origin throughout the world, before the appearance of written sources. This has both established the astonishing brevity of human history and eliminated the reductionist solution of neo-Darwinian socio-biology.
The changes in human life in past 10,000 years, let alone the past 10 generations, are too great to be explained by a wholly Darwinian mechanism of evolution via genes. They amount to the accelerating inheritance of acquired characteristics by cultural and not genetic mechanisms.
In short, the DNA revolution calls for a specific, historical, method of studying the evolution of the human species. It also provides us with a rational framework for a world history. History is the continuance of the biological evolution of homo sapiens by other means.
Secondly, the new evolutionary biology eliminates the distinction between history and the natural sciences and bypasses the bogus debates on whether history is or is not a science.
Thirdly, it returns us to the basic approach to human evolution adopted by prehistorians, which is to study the modes of interaction between our species and its environment and its growing control over it. That means asking the questions that Marx asked. "Modes of production", based on major innovations in productive technology, in communications, and in social organisation - but also in military power - have been central to human evolution. These innovations, as Marx was aware, did not and do not make themselves. Material and cultural forces and relations of production are not separable. They are the activities of men and women in historical situations not of their making, acting and taking decisions, but not in a vacuum.
However, the new perspectives on history should also return us to that essential, if never quite realisable, objective of those who study the past: "total history". Not a "history of everything", but history as an indivisible web in which all human activities are interconnected. Marxists are not the only ones to have had this aim, but they have been its most persistent pursuers.
Not the least of the problems for which the perspective of history as interaction is essential, is one that is crucial for the understanding of the historic evolution of homo sapiens. It is the conflict between the forces making for the transformation of homo sapiens from neolithic to nuclear humanity and the forces whose aim is the maintenance of unchanging reproduction and stability in human social environments. For most of history, the forces inhibiting change have usually effectively counteracted open-ended change.
Today this balance has been decisively tilted in one direction. And the disequilibrium is almost certainly beyond the ability of human social and political institutions to control. Perhaps Marxist historians, who have had occasion to reflect on the unintended and unwanted consequences of human collective projects in the 20th century, can at least help us understand how this came about.