A word from the wise to the not-so-wise

We still have much to learn from our forebears, to whom interdisciplinarity came naturally. Alex Danchev unbottles the spirit of a revolutionary age

We need history," said Nietzsche, "but not the way a spoiled loafer in the garden of knowledge needs it." The Cambridge History of Eighteenth-Century Political Thought ( CHECPT ) comes as a bracing draught for spoiled loafers, young and old. The editors speak of a kind of hundred years' war between intellectuals, publicists and even some heads of state, bracketed by an English Revolution at one end (in 1688) and a French Revolution at the other (in 1789), with an American Revolution in between (in 1776). The 18th-century republic of letters ran rampant through the garden of knowledge. The CHECPT seeks to capture the essence of those rumbustious engagements - to bottle the spirit - and perhaps in some fashion to mirror in miniature the contemporary ideal of the Encyclopédie , as conceived by the polymathic Denis Diderot and Jean d'Alembert: an open society of scholars, scientists, writers and artists collaborating in a concise summation of theoretical knowledge and, what is more, a manual for moral improvement.

Naturally enough, their Cambridge successors have scaled down their ambitions somewhat. Nevertheless, glints of that animating impulse remain. The history they have compiled is not primarily the history of great men or great books, but of great issues - issues of moment in the public and private lives of nations - condensed, contextualised and connected. To this end, the work is presented in a six-part thematic scheme: the ancien régime and its critics; the new light of reason; natural jurisprudence and the science of legislation; commerce, luxury and political economy; the promotion of public happiness; and the Enlightenment and revolution.

Each part contains four expository chapters, closely interrelated. In Part one: "The spirit of nations" (Sylvana Tomaselli); "The English system of liberty" (Mark Goldie); "Scepticism, priestcraft and toleration" (Richard H. Popkin and Mark Goldie); "Piety and politics in the century of lights" (Dale K. Van Kley). In Part two: "The comparative study of regimes and societies" (Melvin Richter); "Encyclopaedias and the diffusion of knowledge" (Daniel Roche); "Optimism, progress and philosophical history" (Haydn Mason); "Naturalism, anthropology and culture" (Wolfgang Pross). In Part three: "German natural law" (Knut Haakonssen); "Natural rights in the Scottish Enlightenment" (James Moore); "The mixed constitution and the common law" (David Lieberman); "Social contract theory and its critics" (Patrick Riley). In Part four: "The early Enlightenment debate on commerce and luxury" (Istvan Hont); "Physiocracy and the politics of laissez-faire " (T. J. Hochstrasser); "Scottish political economy" (Donald Winch); "Property, community and citizenship" (Michael Sonenscher). In Part five: "Philosophical kingship and enlightened despotism" (Derek Beales); "Cameralism and the sciences of the state" (Keith Tribe); "Utilitarianism and the reform of the criminal law" (Frederick Rosen); "Republicanism and popular sovereignty" (Iring Fetscher). In Part 6: "The American Revolution" (Gordon S. Wood); "Political languages of the French Revolution" (Keith Michael Baker); "British radicalism and the anti-Jacobins" (Iain Hampsher-Monk); "Ideology and the origins of social science" (Robert Wokler).

To this is appended a hefty bibliography of primary and secondary works, and nearly a hundred pages of potted biographies, from Jacques Abbadie to John Joachim Zubly, personages great and small, Ouvres major and minor, a generous assortment or a recherché selection. Some of them prompt a stab of recognition (Samuel Johnson, the Marquis de Sade) yet scarcely figure in the preceding text. They are given their potted due, nonetheless, occasionally in rather plonking terms: "From his name is derived 'sadism'."; "He wrote prolifically." Perhaps it is unfitting to cavil. Not for Cambridge University Press the miserable expedient of consigning the apparatus to the internet. It is all here in hard covers. At the outrageous price of £110, it ought to be. Why no paperback?

The chapters themselves are of an exceptionally high order. In conception and execution, the volume is an outstanding success. It is rare indeed for a work by divers hands to attain such consistency and coherence. The incidental losses are easily recouped elsewhere. Fuller biographical treatments of the principal figures (Bentham, Hume, Kant et al) are readily available in works such as The Oxford Companion to Philosophy (1995), masterminded by Ted Honderich, which would make an admirable companion volume. There are dense passages, to be sure, and some clotted genealogies ("'Rational Dissent' emerged via Arminian and Socinian defection from old Presbyterian Dissent, joined by some notable Calvinist Independents such as Price and Priestley, and by Unitarian exiles from the Anglican ministry"); but there is hardly any technical or analytical impenetrability of the "'snow is white' is true if, and only if, snow is white" variety that can be such a trial to the non-initiate.

Issue after fundamental issue is unpacked across a vast terrain of new knowledge. The editors make the point that political thinking and writing in this period was not circumscribed by later disciplinary boundaries - a sharp point and also a humbling one. In the 18th century, the effortful goal of latter-day dirigistes in research councils and management teams was already fulfilled. The philosophes needed no instruction in the art of intellectual adventurousness. Interdisciplinarity came naturally to them.

Some of the framing and explaining is masterly. "At the heart of social contract theory," writes Patrick Riley in his introduction, "is the idea that political legitimacy, political authority, and political obligation are derived from the consent of the governed, and are the artificial product of the voluntary agreement of free and equal moral agents. On this view, legitimacy and duty depend on a concatenation of voluntary individual acts, and not on 'natural' political authority, patriarchy, theocracy, divine right, necessity, custom, convenience, or psychological compulsion.

Michael Oakeshott was thus right to call contractarianism a doctrine of 'will and artifice'." And off we go on the contractarian roller-coaster.

Words and worlds were turned upside-down. In this age of revolutions, the very idea of revolution changed its meaning. "Those who make revolutions, those who wish to do good, must sleep only in the tomb," proclaimed the ecstatic Saint-Juste (born 1767, guillotined 1794). "A revolution is a heroic undertaking whose authors walk between perils and immortality. The latter is yours if you know how to immolate enemy factions." By the middle of the century, "revolution" was no longer governed by the astronomically inspired idea of an orbit or a cycle. It had been hijacked and supercharged. It had become active, purposive, expansive, as never before.

Keith Michael Baker concludes: "In the course of the French Revolution - indeed, in the very conceptualisation of the 'French Revolution' - these competing notions were fused in an explosive combination. When revolution was simultaneously experienced as a crisis and reoriented towards the future, when it became the awesome passage towards universal transformation, even to think of ending it was to lapse into counter-revolution. The Revolution could not be closed before the work of philosophy - the regeneration of humanity - was completed. The notion was a powerful one, destined for a momentous future."

Not the least instructive aspect of the CHECPT is the way in which the voices of the past speak to our present condition. Eighteenth-century political discourse is immensely rich - especially in invective. In England, the person and system of Prime Minister Robert Walpole (1722-42) provoked an opposition of stunning ferocity, intellectual ingenuity and literary fecundity, evoked with some relish by Mark Goldie. "These campaigns benefited from a lavish literary renaissance, which opened with Swift's Gulliver's Travels in 1726. Walpole was here caricatured as Flimnap in the voyage to Lilliput, the impresario of the circus tricksters who win pretty ribbons from the Lilliputian king. In John Gay's Beggar's Opera (1728), Walpole was represented as Captain Macheath, the highwayman. Or maybe he was Peachum, the receiver of stolen goods. The play prompted the Government to impose censorship on the theatres. Gay's play was in part a reprise of St Augustine's story, in The City of God , of the encounter between the Emperor Alexander and a pirate: the moral is that a ruler is merely a pirate who has achieved larceny on a grand scale. This trope was repeatedly refashioned, from Henry Fielding's Jonathan Wild (1743) to Bertolt Brecht's Threepenny Opera (1928). In Alexander Pope's poem The Dunciad (1728), Walpole was portrayed as the Great Dunce, the puppeteer of a band of knaves and fools. In David Mallet's play Mustapha (1739), Walpole becomes an evil bashaw (Pasha). The intricate iconography of William Hogarth's paintings The Harlot's Progress (1732) also yields up anti-Walpolean satire. The allegorical canon of evil personae for Walpole was inexhaustible: he was equated with such royal favourites and grasping ministers down the ages as Sejanus, Tiberius, Clodius, Gaveston, Wolsey and Buckingham."

Jonathan Swift, where are you now that we need you?

In France, the ten-volume work produced by the Abbé Raynal, A Philosophical and Political History of the Settlements and Trade of the Europeans in the East and the West Indies , commonly known as the Deux Indes (1770), was ranked in its time with that of Voltaire, Montesquieu and Rousseau. It has since come to light that parts of it were co-authored (anonymously) by Diderot and others. "More than any other major work of the century, the book systematically reversed prior judgments about the old world's political and moral superiority," as Melvin Richter explains. "It did so by inverting the values of the polar oppositions long made in European thought between barbarism and civilization, between l'homme sauvage and l'homme policé , savage man and civilised man."

In the 21st century, the lesson is being painfully relearnt. One side, however, seems to understand it only too well. In Iraq, amid the rubble of Fallujah, a teenager came up to the leader of a US Army patrol. Gesturing to a pile of rubbish that filled a space where a building had been, he asked in a loud voice: "Why don't you Americans clean up the garbage?" With a sigh, the patrol leader replied: "Why don't you clean it up yourselves?"

The boy said, theatrically: "Oh, because we're not like you Americans. We are savage and primitive people."

In a passage of his Idea for a Universal History (1784), which Isaiah Berlin was to appropriate for his own philosophy, Immanuel Kant declared that "nothing straight can be constructed from such warped wood as that which man is made of". Kant was the master. In the seventh proposition of that same work, he argued: "We are cultivated to a high degree by art and science. We are civilised to the point of excess in all kinds of social civilities and proprieties. But we are still a long way from the point where we could consider ourselves morally mature." How wise we were, once upon a time.

Alex Danchev is professor of international relations, Nottingham University.