“All history,” as R.G. Collingwood said, “is the history of thought.” One traditional view of history, now discarded, is that it is virtually synonymous with the history of ideas—history is composed of human actions; human actions have to be explained by intentions; and intentions cannot be formed without ideas. On a grander scale, the doctrines of Christianity were the core of the providential universal histories that persisted until the 18th century, since the acceptance—or rejection—of Christian ideas was considered history’s master plot. When the providential argument in its simpler medieval form lost credibility, it was reformulated by Vico, with his conception of the tropes appropriate to the different ages of humanity, and by Hegel, whose “objective” idealism identified the development of Spirit, or the Idea, as the motor of history. In the techniques of historical investigation too, the history of ideas was the source for the hermeneutical skills required for reading complex texts. The interpretation of ancient laws and religious doctrines was the workshop in which were forged the tools that were subsequently used in all historical work.

It was not until the speculative schemes that identified the development of ideas with the historical process were generally discredited, and its hermeneutic techniques thoroughly naturalized elsewhere, that intellectual history became a specialty—the first specialized field to supplement the traditional historical specialties of political, diplomatic, and military history. It emerged slightly earlier than social history, and for a time the two were allies in a joint struggle to gain acceptance. The incompatibility—indeed, antagonism—between the two emerged only later.

Confusion can arise because history of ideas and intellectual history are sometimes treated as synonyms. The former is properly the name of a field of study in which ideas themselves are the central subject. The most sophisticated approach to the history of ideas was formulated by Arthur Lovejoy (1873–1962). Lovejoy focused on what he called “unit ideas,” such as the notion of a Great Chain of Being extending from God through the angels to humans down to the least-complicated life-forms. Lovejoy traced this idea from its classical roots through the 19th century in both philosophical and literary elaborations. Philosophical or theological doctrines (e.g., Plato’s theory of Forms, or Manichaeism, a dualist religious movement founded in Persia) lend themselves best to the unit-idea mode of study. One difficulty with the history of unit ideas, however, is that it is often difficult to establish the identity of an idea through time. The term natural law, for example, meant quite different things to Stoic philosophers, to Thomas Hobbes, to John Locke, and to the prosecutors of Nazi war criminals at the Nürnberg trials (1945–46); the meaning of the same words can change radically. This drives the historian to the Oxford English Dictionary or its equivalents for other languages to get a first take on the history of meaning changes. This step, however, must be supplemented by extensive reading in the contemporary literature, not only to see what semiotic load the words bear but also to see what controversies or contrary positions might have been in the mind of the writer.

The phrase intellectual history did not come into common usage until after World War II. It seems to owe its first currency to The New England Mind: From Colony to Province (1953), by Perry Miller (1905–63), who required it for his approach to the complex of religious, political, and social ideas and attitudes in Massachusetts in the 17th and 18th centuries. The focus of intellectual history has been not on the formal analysis of ideas, as in the history of ideas, but on the conditions of their propagation and dissemination. It also considers not just the formally articulated ideas of theorists or poets but also the sentiments of ordinary people. Even popular delusions come within the ambit of intellectual history; in this respect it intersects studies within psychohistory and the cultural history of mentalités.

Perhaps because their area of study is so ill-defined, intellectual historians have been unusually reflective and argumentative about the methods appropriate to their work. One methodological controversy was initiated in the 1960s by Quentin Skinner. Skinner questioned the custom in political philosophy of identifying certain “eternal” questions (such as “Why does anyone have an obligation to obey the state?”) and then arraying various political texts according to the answers they give. This procedure, he argued, led to invalid historical conclusions, since the eternal questions were the constructions of modern political philosophers and reflected modern concerns. Taking his cue from the ordinary language philosophy of John Langshaw Austin and other postwar Oxford philosophers, Skinner contended that the task for the historian of political thought was to discover what effect the writer of a text intended it to have.

Skinner’s best example was Locke’s Second Treatise of Civil Government (1690), which for generations had been paired with Thomas Hobbes’s Leviathan as one of two versions of a social contract theory. Skinner and his colleague John Dunn started from the obvious but often ignored fact that there was a first treatise by Locke that refuted the idea that political power devolved from the power that God gave to Adam. Absurd as this idea seems to contemporary philosophers, it nevertheless commanded widespread assent in 17th-century Britain. Similarly, a great deal of controversial writing was then done by clergymen, and Locke (as is evident from his many quotations of the Anglican divine Richard Hooker) participated actively in this discourse. On the other hand, there is very little evidence that Locke was responding to Hobbes.

In no branch of history has the challenge of postmodernism and deconstruction been felt more keenly than in the history of ideas. Here the goal has been to interpret past texts; the intentions of the author, as revealed in those texts, set limits to possible interpretations even where they do not mandate a single one. Deconstructionists such as Jacques Derrida assert that the intentions of the author can never be known and would be irrelevant even if they could be. All that an interpreter has is the text—thus, Michel Foucault, drawing upon the work of literary critic Roland Barthes, declared the “death” of the author. No single meaning can be assigned to the text, because what it does not say may be more significant than what it does. Even what it does say cannot be reduced to a stable meaning, because of the intrinsic opacity and slipperiness of language. (Most words in ordinary usage have several different definitions; there is no way to use them so as to totally exclude all traces of the other meanings. Puns, of which Derrida was fond, illustrate these “surplus” meanings.)

The subversiveness of such views for the traditional practice of the history of ideas is obvious. Derrida’s advocates presented his ideas as liberating and as allowing critics to exercise the same creativity as imaginative writers. The apparent concession to total relativism, however, has seemed too high, not least because it renders the deconstructionist position vulnerable to the paradox of relativism (if the deconstructionist is right that there are no stable meanings, then there is no stable meaning to the assertion that there are no stable meanings, in which case the deconstructionist position cannot even be formulated). Derrida occasionally complained of being misread. But the deconstructionist position is not absurd, nor can it be refuted by saying that few historians have accepted it.

Military history

Soldiers in battle were the theme of the earliest Greek epic and the earliest histories. It has not lost its interest for modern readers and writers. The focus of academic military history, however, has changed as markedly as the nature of modern warfare has changed. The campaigns of the American Civil War, with their chesslike maneuvering and great set-piece battles, continue to fascinate, but attrition and pounding by superior force assumed an ever-greater role in 20th-century military strategy, despite yielding few brilliant generals or individual heroes. On the other hand, World War I was the first European war to be fought by literate armies, and the soldiers in that conflagration created not only a great literature but also a mass of material about their experiences. In The Great War and Modern Memory (1975), Paul Fussell made full use of these documents to produce an account of life in the trenches. Although the literary output of soldiers in World War II was much less significant, the American writer Studs Terkel, using techniques of oral history, managed to compile in The Good War (1984) a comparable panorama of its participants, including those on the home front. Perhaps the leading exponent of military history as the social history of war is John Keegan, whose work ranges from the Battle of Agincourt in 1415 to the wars of the 21st century.

Political history

For many people, and for many years, “history” simply meant political history. A large proportion of published works by historians was devoted to political history as late as the 1970s, but even before that time historians had begun to examine other topics. Although E.A. Freeman’s slogan “History is past politics” no longer rings true, it is safe to say that political history will continue to be a prominent part of historical writing and will challenge the subtlety, worldly wisdom, and narrative powers of historians as long as history is written.

The primary goal of political history in the immediate postwar years was to supplement (or, in the minds of some, to supplant) the historian’s traditional reliance on narrative with a scientific or quantitative approach; inevitably, this endeavour came to be called “new political history.” It was to be, as William Aydelotte put it, “a sedate, hesitant, circumspect, little behavioral revolution” in American historical practice. The postwar United States furnished some innovative young historians who combined an interest in political history with a program for making it more scientific. Among the most systematic of these scholars was Lee Benson, author of an influential work that applied quantitative techniques to the study of Jacksonian democracy. “By 1984,” he predicted in 1966,

a significant proportion of American historians will have accepted … two basic propositions: (1) past human behavior can be studied scientifically; (2) the main business of historians is to participate in the overall scholarly enterprise of discovering and developing general laws of human behavior.

Wherever possible, all statements in historical works should be formulated so precisely as to be “verifiable.” Implicitly but vaguely quantitative terms (e.g., most or significant proportion) should be replaced by numerical expressions.

Quantitative data to support such ambitions were available for elections. Using what he found in New York state, Benson succeeded in showing that party affiliation was largely determined by ethnic and cultural loyalties and remained surprisingly immune to the issues raised by party platforms or political speeches.

The University of Iowa was another hotbed of quantitative approaches, and electoral statistics of Iowa and other Midwestern states soon joined those of New York. The new political historians also established an archive of national election data at the University of Michigan, which they hoped to use to prepare a truly comprehensive electoral history.

Less-ambitious quantitative projects focused on parliamentary bodies. Lewis Namier (1888–1960), probably the greatest English historian of his generation, undertook the biographical study of members of Parliament. Namier borrowed the prosopographic technique of Ronald Syme, a historian of ancient Rome, which involved tracing the family connections, sources of income and influence, and offices held by a defined group of the political elite. This approach was most useful for the study of oligarchic regimes and hence was especially suitable for the Roman Senate and mid-18th-century British parliaments. The main effect of such work was to de-emphasize the impact of political ideologies and to assert the importance of kinship and personal relations in deliberative assemblies.

More directly quantitative was the work of Aydelotte, who investigated the conventional claim that the English Corn Laws (protective tariffs on grain imports) were abolished because members of Parliament who represented manufacturing districts wanted the cheapest-possible food for their workers (allowing the lowest-possible wages). As plausible as this view was, significant correlations frequently failed to appear.

The new political historians carried the quantitative program into the stronghold of traditional historiography. Terms such as impressionistic, anecdotal, and narrative acquired dismissive connotations. More-traditional historians were admonished for excessive reliance on literary evidence (i.e., anything that could not be quantified).

A generation later, the debate over quantification fizzled out, leaving some permanent mark on political history. Few would now deny the value of some quantitative studies or the desirability of precision in historical language. The habit of collaboration with other historians and membership in research teams, virtually unknown earlier, is now well established. A number of intuitively obvious interpretations have been shown to be exaggerated or plainly wrong.

On the other hand, it is clear that quantification in political history was oversold. Its idea of scientific procedures was startlingly old-fashioned, and many of the studies based solely on quantification failed to produce significant results. Sometimes things already believed were confirmed—not a useless exercise but not a high priority either. More-interesting correlations often failed the significance test or showed inexplicable relationships. Finally, attention was diverted to bodies of data that could be quantified. The most judicious of the new political historians warned against the exclusive reliance on quantification and recognized that archival research would remain indispensable, especially in the traditional fields of constitutional, administrative, and legal history.