The idea that the English have a national character sounds plausible enough, until you start to try to pin it down. Are the English the romantic, imaginative people of Shakespeare and Keats, or the efficient imperialists who lorded it over India and Africa? The introverts whose motto is “No sex please, we’re British,” or the swingers of Carnaby Street and Cool Britannia? The sneering redcoats of the American Revolution, or the plucky Londoners of the Blitz? Is the archetypal Englishman John Bull, or Colonel Blimp, or Monty Python? Whoever he is, it begins to look like he has a split personality: he is an adventurous homebody, coldly sentimental, genteelly vulgar. As Daniel Defoe wrote more than 300 years ago, “from a mixture of all kinds began / That het’rogeneous thing, an Englishman.”

The only thing all these myths of Englishness have in common is the premise that there is such a thing as the English character — an enduring national essence that separates the people of the sceptred isle, for good or ill, from their fellow men. But for Peter Mandler, Englishness is less an essence than a mirror, in which observers of every stripe see their own images. In “The English National Character” (Yale University Press, 348 pages, $35), Mr. Mandler is not out to define that elusive concept, but to see how generations of English and foreign writers have defined it, argued about it, and finally, perhaps, discredited it. In the process, his densely informative work offers a superb example of how to write, in the words of his subtitle, “the history of an idea”

Indeed, Mr. Mandler, a historian who teaches at Cambridge University, shows that the first step towards understanding any idea is to recognize that it has a history. The whole point of national character is that it is timeless, something that endures beneath changes in manners. But as Mr. Mandler shows, not only have the English never agreed on what their character is; they have not always even thought they had one, or needed one.

For England, he writes, the 18th century was “the patriotic century par excellence,” as a series of wars against France helped to unify national sentiment. But that sentiment usually took the form of pride in English institutions — Parliamentary government, the rule of law, freedom of speech — rather than English character. To David Hume, the superiority of England lay precisely in the freedom that made it possible for men to develop their individual natures, instead submitting to a collective one. “Of any people in the universe,” he wrote, the English “have the least of a national character.” This Enlightenment view was profoundly cosmopolitan and optimistic. What made the English so enviable was not an innate character, which other peoples could only envy, but a set of institutions, which they could emulate.

As Mr. Mandler shows, this emphasis on English civilization, rather than English character, never completely lost its power. It helps to explain why, in the nationalist 19th century, the English never fell hard for those racial and national myths that were so seductive on the Continent. They did not have to be proud of their ancestors’ blood when they could be proud of their ancestors’ accomplishments.

Even so, the 19th century did see a flourishing dialogue about just what made the English English. Not coincidentally, Mr. Mandler shows, that debate was most intense around the years of the two Reform Acts, in 1832 and 1867, which greatly expanded the voting franchise. If Britain was to be a democracy, it became urgent to find out whether the people as a whole could be trusted with power — indeed, whether “the people” even existed, outside the rhetoric of Jacobins. Was nation, in fact, more important than class? Did a gentleman and a laborer share a national character?

Not surprisingly, such questions were more likely to be answered in the affirmative by democrats and liberals than by conservatives. That is why, for most of the Victorian age, it was liberals who were most interested in defining national character — a striking contrast to the present, when the notion is much more congenial to the right. The great liberal philosopher John Stuart Mill was the first to call for a “Science of Character … including the formation of national and collective character,” a new branch of study that he dubbed “ethology.” The Victorians’ fondness for tracing the English love of liberty back to their hypothetical Anglo-Saxon ancestors was part of the same democratic tendency.

The fad for “Teutonism” might have threatened to turn into a more sinister, biological racism, as it would in Germany. But one of Mr. Mandler’s arguments is that, contrary to current academic stereotypes, racial thinking found little purchase in Victorian culture. The influence of Christianity, with its emphasis on the individual soul, worked against racism. So too did the diversity of the United Kingdom itself, where English, Scottish, Welsh and Irish citizens allegedly shared a single British identity. In the late 19th century, when the eugenic movement found eager adherents in America, England was blessedly free from the desire literally to engineer its national character.

In the 20th century, Mr. Mandler writes, the idea of the English character saw its apotheosis and its rapid decline. The high point came during World War II, which “seemed to vindicate the English national character — both the idea that nations did have a character and that, in the English case, it was made of the right stuff.” To this day, our most positive myths of Englishness invoke the resilience and courage of 1940. But in a surprisingly short time, wartime solidarity gave way to the individualism of the 1960s and after. Mr. Mandler titles his last chapter “England after Character?” and the question is mainly answered in the affirmative. When John Major tried, in a 1993 speech, to evoke “the country of long shadows on county grounds, warm beer, invincible green suburbs, dog lovers,” and so on, he was met with what Mr. Mandler describes as “a volley of sniggers.”

Mr. Mandler warns us, however, against taking this development as a sign of decadence, as some English conservatives are quick to do. After all, the English of Elizabeth’s day never conceived of such a thing as national character, yet they were a great nation. “Our culture,” Mr. Mandler concludes, “is so saturated with means of thinking about ‘nation’ that we do not have to rely on the clumsy semiautomatic mechanisms of brute psychology.” Instead of its character, a nation can be defined by its institutions, laws, and customs, or by a feeling of identity and mutual concern. After all, on this side of the Atlantic, we have never talked as much about the American character as about the American Dream. Yet that promise of freedom, and the institutions that make it possible, have fostered a remarkable sense of solidarity. Maybe “national character” is merely a crutch the English no longer need.

akirsch@nysun.com