The Brothers Koerbagh

You might have expected the idea of Enlightenment to have gone out of fashion by now. Indeed you might have expected the entire pack of tacky Victorian labels for cultural periods – the Middle Ages, Renaissance, Romanticism, Modernity and so on – to have fallen into disuse long ago. They seem to belong to a world we have lost, where the whole of history was a brief, memorable tale spanning little more than a hundred generations. It was a world where history began in Homeric Greece or the Garden of Eden and marched up to the present in a few manly strides before moving to a final consummation, which might not be so far away. But does anyone believe that kind of history any more? It is over a century since historians started getting their professional act together and coming to terms with global diversities and Darwinian time-scales; and you might have thought their first priority would have been a ban on the outmoded simplicities of period thinking.

The 20th century was, however, an epoch of unprecedented epoch-mania. Nothing was allowed to be its own individual self; everything had to be interpreted in terms of what was typical for its time. A handful of nit-picking philosophers and pukka historians may have frowned their disapproval, but why should anyone care as long as the trade in periods and period styles was booming? Critics, sociologists and cultural commentators had a vested interest in the idea of history as a single time-line divided into distinct epochs each with its own cultural or philosophical signature, and they were not about to give up the discursive rewards of their unreflective historicism.

One of the strangest things about the century of period thinking was that all its stories led back to the same place. There might be dozens of alternative histories of the present age, but they all intersected at some point in the 18th century known as the Age of Reason, or more vividly the Enlightenment (or le siècle des lumières, die Aufklärung or l’illuminismo). Essentially, the Enlightenment was taken to be Europe’s concerted effort to cleanse itself of the last residues of barbarism and medieval superstition and replace them with liberalism, science and secular philosophy. Everyone agreed that the Enlightenment reached its prime in France in or about the third quarter of the century, and its principal heroes were always referred to as Philosophes. (Philosophy may not have been their strong suit; but the word was left untranslated in deference to the quintessential Frenchness of the whole affair.) Its most glorious achievement was taken to be Diderot’s Encyclopédie – 17 grand folio volumes compiled between 1751 and 1765 with dozens of collaborators, including d’Alembert, Quesnay, Rousseau and Voltaire. But it was also implicated in the origins of the French Revolution, and its reputation went into decline as the Revolution lost its youthful bloom; for a while, indeed, it was totally eclipsed by the Romantic reaction with its factitious liking for the Middle Ages. Before long, however, medievalism became a term of ridicule again, and the Enlightenment achieved a spectacular comeback by transforming itself into all-conquering Modernity and expanding to colonise the globe. When Modernity eventually lost its way and had to abdicate in favour of its designated successor, the publicists for Postmodernism had a ready-made explanation at hand: since Modernity was just the Enlightenment writ large, the crimes and calamities of the 19th and 20th centuries could all be traced to the 18th century and its over-investment in the power of reason. Postmodernism was nothing if not post-Enlightenment.

The idea of the Enlightenment goes back to the 18th century itself, in particular to Kant and a miniature essay called ‘What Is Enlightenment?’ which he wrote in 1784. He started by acknowledging that we all have an ingrained desire to live lazily, even if it means bending our knees to tyranny and locking our imaginations in a prison of old-fashioned clichés. But we are also endowed with a contrary impulse: an urge to throw off our intellectual shackles and start thinking for ourselves – in other words, an instinct for Enlightenment. As Kant defined it, Enlightenment was simply the process of ‘humanity’s escape from self-imposed tutelage’, and even if our habitual cowardice and timidity would always try to thwart it, it was so deeply embedded in human nature that it was bound to triumph in the end, not only in individuals but across nations, too, and eventually throughout the human race.

The definition is an ingenious amalgamation of a priori philosophy, empirical history and political special pleading. It enabled Kant to make Enlightenment not only a necessary and universal structure of the human mind, but also a precarious outcome of historical contingencies. No doubt every generation contained a scattering of passionately enlightened thinkers, but, according to Kant, their ardour could not take hold among ‘the great unthinking masses’ until the political conditions came right. The social propagation of Enlightenment presupposed a powerful but forbearing state prepared to protect the ‘public use of reason’ and guarantee the right of authors to publish their work without fear of censorship or persecution. ‘Once freedom is granted,’ Kant concluded, ‘Enlightenment is almost sure to follow.’ He was convinced, moreover, that Enlightenment’s day was dawning even as he wrote: he had the good fortune to live in an epoch – ‘the century of Frederick’ he called it – in which the promise of general Enlightenment could at last be fulfilled. He conceded that he did not yet live in ‘an enlightened age’; but thanks to his liberal Prussian king it was at least an ‘Age of Enlightenment’.

Kant’s confidence in the ultimate triumph of Enlightenment never wavered, though it took a terrible battering in the remaining twenty years of his life. Frederick the Great died in 1786, to be succeeded by the notably unenlightened Frederick William II; and if the storming of the Bastille seemed to herald an enlightened age in France (‘I have seen the glory of the world,’ Kant said), the subsequent course of the Revolution was not so gratifying. A generation later, however, the amalgam of philosophical necessity, historical contingency and political duty in Kant’s conception of Enlightenment provided Hegel with much of the material for his Phenomenology of Spirit. Hegel was perhaps the first thinker to treat the Enlightenment as a thing of the past, pronouncing in 1807 that it had always been destined to fail because, for all its harping on about reason, it was nothing like as rational as it thought. When it tried to discredit traditional Christianity as a tissue of absurdities created by conspiracies of priests, for example, it was not only overlooking the implicit rationality of popular religious practice, but also painting a prophetic self-portrait. It was the catastrophe of Jacobin supremacy in Paris in 1793-94 that revealed the true meaning of the Enlightenment’s infatuation with its own cold calculations. The fake religiosity of the Festival of the Supreme Being hovered over the corpse of Revolutionary reality like ‘the exhalation of a stale gas’, as Hegel put it, and a monstrous equation between suspicion and guilt led straight to the Terror. The absolute freedom of the Enlightenment was the negation of trust, faith, love, life and history: all it meant was death by guillotine – ‘the coldest and meanest of all deaths’, Hegel said, ‘with no more significance than cutting off a head of cabbage or swallowing a mouthful of water’.

Subsequent philosophical discussions of the Enlightenment have done little more than echo the original masters, usually with a bias towards Hegel and Romanticism. In his urbane study of The Philosophy of the Enlightenment (1932), however, Ernst Cassirer launched an appeal against ‘the verdict of the Romantic Movement on the Enlightenment’. Accusations of frigid intellectualism and complacent authoritarianism were unfounded, according to the great Kantian. Despite its occasional bouts of bumptiousness, the Enlightenment had cured European thought of its fixation on reductive analyses based in mechanics and geometry and taught it to prefer holistic syntheses rooted in organic natural harmonies. The Enlightenment, in Cassirer’s opinion, had successfully carried out all the ‘great intellectual tasks which 18th-century thought had to accomplish’.

Twelve years later, in exile in Los Angeles, Horkheimer and Adorno launched an ultra-Hegelian counter-attack. In Dialectic of Enlightenment they asked themselves ‘why mankind, instead of entering into a truly human condition’ was ‘sinking into a new kind of barbarism’. They scrutinised ‘the habits and tendencies of the spirit of the age’ and found themselves looking back to the Enlightenment for an answer. They discovered, naturally enough, that until the opening years of the French Revolution it had been a boldly progressive movement; indeed they confessed that their own commitment to ‘social freedom’ was ‘inseparable from enlightened thought’. On the other hand, they also found that the Enlightenment had turned out to be inherently self-destructive: its ambition to abolish myth was inherently mythological, and in the end the whole movement had degenerated into reactionary savagery. In the long run, indeed, the Enlightenment was responsible for the crazed subjectivism and murderous manipulativeness that was currently wrecking the Europe they had fled.

A rather similar analysis was put forward in 1956 by Isaiah Berlin, whose anthology The Age of Enlightenment offers an intellectual prospectus for his subsequent brilliant career. ‘The 18th century,’ he wrote, ‘was perhaps the last period in the history of Western Europe when human omniscience was thought to be an attainable goal.’ The thinkers of the Age of Enlightenment, though they disagreed about some things, were united in the conviction that ‘the truth was one single, harmonious body of knowledge . . . which could solve all theoretical and practical problems for all men everywhere for all time.’ It is no surprise to learn that this ‘heroic attempt’ was doomed to failure: we now knew, according to Berlin, that philosophy could never be reduced to mechanics and that technology would never solve the problem of values, and we should at last learn to live with the illimitable variousness of human aspiration.

In 1960 the sagacious story was retold in The Age of Reason by Harold Nicolson, Berlin’s former boss at the wartime Ministry of Information. Like Berlin, Nicolson thought that the prologue to the Enlightenment had been played in England at the end of the 17th century, when ‘Newton first taught men that existing myths were not in accord with scientific fact’ and ‘Locke taught men that ideas were not innate . . . and that toleration in politics and religion is the glory of civilised man.’ But the Age of Reason itself was ‘dominated by French culture’, and ‘it was by the Philosophes and the encyclopédistes that the thought and taste of the civilised world was formed.’ Voltaire with his sardonic smile was ‘the supreme intellectual influence of the 18th century’, championing the oppressed and ushering in an ‘age of scepticism’; but he was complemented by Rousseau, whose emotional genius inaugurated ‘the age of sensibility’. It was a winning combination, but an ominous one, too. ‘Voltaire transformed the thoughts, and Rousseau the feelings, of the 18th century,’ according to Nicolson; and if Voltaire’s caustic wit was ‘one of the causes of the French Revolution’, then Rousseau’s gospel of sentiment was the other. Together they ‘propagated the fictions that all men are born equal, that sovereignty rests with the people, that reason is infallible, and that no governmental enactment need be regarded as valid if it could be shown to violate the Law of Nature’. But of course it would all end in madness and disaster: ‘it needed the Reign of Terror,’ Nicolson concluded, ‘to convince men that “the People” could not be relied on to be invariably just, compassionate and righteous.’

Charles Taylor put forward a similar analysis in Hegel (1975), though he had fewer regrets about the obsolescence of ‘the Enlightenment vision of society’ with its self-sufficient individuals pursuing an atomised agenda of individualistic rights. Lyotard cheerfully replayed the dialectic of myth and Enlightenment in The Postmodern Condition (1979); and Alasdair MacIntyre shed no tears over the ‘failure of the Enlightenment project’ in After Virtue (1981). By this time Enlightenment-bashing was becoming a rather stale sport, and it is not surprising that by 1985, in a timely book entitled The Philosophical Discourse of Modernity, Habermas was warning of the dangers of conservative irrationalism and calling for a return to the values of Kantian Enlightenment.

All these writers were philosophers rather than historians, and perhaps that is why they were happy to recycle old stories about the 18th century without bothering to check them against archival research. They were content, for the most part, to repeat the familiar generalisations and illustrate them with quotations gleaned from recent editions of the classics. Apparently their intellectual consciences were never troubled by the thought that the 18th-century canon might itself be a selective and polemical construct designed to support Kantian or Hegelian interpretations of history. When they philosophised about the Enlightenment, in short, they were taking what R.G. Collingwood called the ‘closed’ approach to intellectual history.

Things could only get better, and the first sign that they were doing so was Peter Gay’s magnificent study, The Enlightenment (1966). Not that Gay was unpartisan. He had fled the insanities of Nazi Germany before the war, and his ‘comprehensive interpretation’ of 18th-century thought was in part an expression of gratitude to the United States, which had welcomed him as a refugee and become his home. Gay presented the thinkers of the Enlightenment as a kind of family, cosy and quarrelsome by turns. He divided them into three generations, neatly filling the period from the English Revolution and the birth of Montesquieu in 1689 to the French Revolution and the death of Holbach in 1789. The patriarchs of Gay’s Enlightenment were Voltaire and his aristocratic friends, who liked to mingle fashionable anti-clericalism with scientific speculation in what they took to be the style of Locke and Newton. Their industrious children – Franklin, Hume, Rousseau, Diderot and d’Alembert – turned this rather muddled family inheritance into a ‘coherent modern view of the world’ which Gay called ‘modern Paganism’: an utterly original intellectual movement, as he saw it, which managed to reject Christianity and indeed religion as a whole without reverting to the pre-Christian world of classical antiquity. In the third generation, the family heirlooms passed to Lessing, Jefferson, Kant and Turgot: high-minded idealists who moved valiantly if sometimes rashly into the field of politics, meeting with many successes in the American Revolution and some in the French one, too. The Enlightenment, in short, had created the ideals on which the best features of modern civilisation depend: ‘secularism, humanity, cosmopolitanism, and freedom, above all, freedom in its many forms’.

His emphasis on paganism was a bit unusual, but Gay’s story shares its basic plot with those transmitted from Kant to Cassirer and Habermas or from Hegel to Horkheimer, Adorno and Lyotard; and the moral he drew was also familiar. The difference was that where they were shamelessly pseudo-historical – they simply displaced their disagreements about politics and philosophy into the field of 18th-century history without bothering to explore it in its own right – Gay went to the trouble of reading the original texts, including those that were non-canonical and out of print; and he reminded us that even the most urbane of the Philosophes were embattled and often afraid, and that none of them possessed the supreme self-assurance – the consciousness of being the manifest destiny of their age – with which subsequent philosophers had endowed them.

Before long Gay’s scrupulous historical habits began to spread, and by 1979, when Robert Darnton investigated the relationship between the Encyclopédie and the book trade in The Business of Enlightenment, it was clear that the study of 18th-century thought was changing out of recognition. From now on it would belong to professional historians who had undergone punitive apprenticeships in dusty provincial archives rather than to philosophers with bees in their bonnets about the meaning of Modernity. And if the chroniclers of the Enlightenment were getting dirt under their fingernails at last, their cast of historical characters was undergoing a similar alteration. The heroes of the Age of Reason were no longer fine ironic spirits like Voltaire, Diderot and their patrician patrons; they were enraged plebeian rebels living in the hinterlands of society and the law and staking everything on the hope of wiping out not only Christianity but also the monarchical forms of political power that went with it.

The new pattern was first traced by Margaret Jacob in a monograph boldly entitled The Radical Enlightenment (1981). Her aim was to discredit the old picture of unworldly Philosophes who were ‘incapable of political action’, and replace it with a roguish gallery of ‘freemasons and republicans’ – people like John Toland, Anglo-Irish freethinker, troublemaker and chancer, and inventor of the notoriously slippery concept of ‘pantheism’. The key text of Jacob’s Enlightenment was not the hugely expensive Encyclopédie, but an anonymous pamphlet called the Traité des trois imposteurs, which seems to have originated in the Netherlands around 1680 and was soon circulating in manuscript throughout Europe. The text varies from copy to copy, but the essential argument was that the so-called Holy Scriptures had been fabricated by conspiracies of priests who somehow managed to pass them off as the word of God. (‘Such,’ said the anonymous and still unidentified authors, a little smugly, ‘is man’s malice and stupidity!’) The earliest printed versions, which came out forty years after the first manuscripts, would sometimes open with an engraving of the ‘three impostors’, one holding tablets of stone, another a cross and the third a book; but since they were all off duty their ingratiating theatrical masks were lowered to reveal their all-too-human faces. The first impostor was of course Moses, whose princely education among the Egyptians meant he had no difficulty pulling wool over the eyes of ignorant and credulous Jews. The second was Jesus, who studied the political cunning of Moses, picked up a few half-understood sentences from Plato and other Greek philosophers, and then surrounded himself with a troupe of voluble imbeciles who were prepared to believe everything he said, even when he claimed that his mother was a virgin and his father a holy ghost. The third of the masters of sacred deceit was Muhammad, who learned everything he needed to know about the art of prophecy from his two infamous predecessors.

The people who compiled, copied and distributed the Traité are still hidden in shadows, but Jacob was surely justified – though she worried about the anachronism – in calling them ‘radicals’. Typically they belonged among the deracinated communities of exiles, outlaws and failed revolutionaries who wandered round Europe at the end of the 17th century, with their principal node of communication in the Netherlands. Jacob pointed out that they were not only ‘political activists’ but also ‘intellectual dissenters’ with an attachment to ‘subversive philosophising’ and an irreverent attitude to sacred scripture, often combined with republicanism, Copernicanism, materialism and a dash of sexual libertinism. If they deferred to any philosophical leader, it was to the enigmatic Dutch Jew Spinoza; indeed the Traité often circulated under the title L’Esprit de Mr Benoit de Spinosa. Spinoza’s own Tractatus Theologico-Politicus, which called for a critical approach to the text of the Bible, had appeared in 1670, but the book he put most of himself into was the Ethics, published in 1677 just after his death at the age of 44. The Ethics is a glorious baroque elaboration of the hypothesis that the Universe is a single unified substance with infinitely many aspects interacting in infinitely complicated ways, and that God and Nature are just two alternative designations for it. A hundred years later, this doctrine would be interpreted as a form of rigorous mystical theism, austerely excluding the sentimental view of God as fussily preparing individual packages of rewards and punishments for each of us. In the meantime, however, Spinoza was regarded as a reckless unbeliever, and his name – along with those of Machiavelli, Hobbes and Herbert of Cherbury – became a byword for absolute atheism and hence, in Jacob’s terms, a rallying point for Radical Enlightenment.

Jacob’s argument involved not only a new appreciation of 17th-century atheism and Spinoza’s early reputation, but also a new understanding of the historical co-ordinates of the Enlightenment: a decisive geographical shift from France to the Netherlands, and an equally decisive chronological shift from the middle of the 18th century to the end of the 17th. Dozens of historians have followed in Jacob’s footsteps, often with scant acknowledgment to her; and if they have all added a few extra pebbles to the cairn, Jonathan Israel now comes along with a massive concrete block. Radical Enlightenment: Philosophy and the Making of Modernity 1650-1750 comprises half a million words of evidence for a systematic underground movement of progressive thought that formed itself around Spinoza in the 1670s and invaded every nook and cranny of European culture in the following half-century. Although Israel closes his story in 1750, the clear implication is that the once celebrated High Enlightenment was never genuinely progressive, but only a reactionary attempt to buy off the forceful dissidence of the authentic Radical Enlightenment that preceded it.

Israel gave a preview of his argument in The Dutch Republic: Its Rise, Greatness and Fall (1995). He was not only authoritative but also pleasingly indulgent towards his subject: with the diversity of its churches, and the freedoms it allowed to women, servants and Jews, not to mention the encouragements it gave to the art of painting, the Dutch Republic was indeed one of the wonders of 17th-century Europe. Descartes chose to spend the second half of his life there, flitting from one set of lodgings to another to avoid superfluous sociability, and the Republic quickly developed an advanced intellectual life based on what Israel called ‘Radical Cartesianism’. Mechanistic physics seems to have been more highly developed there than in France or England, and its implications for philosophy and theology were explored with unparalleled vigour not only in the universities but also among Huguenot and English refugees and in the circles surrounding Spinoza. The Dutch Republic, according to Israel, played an indispensable role in propelling European culture towards ‘toleration, secularisation, classification of knowledge and popularisation’ – in other words, towards Enlightenment. And as well as participating in the moderate ‘mainstream’ Enlightenment, Israel argued, the Netherlands had also nurtured a ‘Radical Enlightenment’ which originated in Spinoza and found its ‘most sensational’ expression in the Traité des trois imposteurs.

In the earlier book, Radical Enlightenment was seen as a movement within the Dutch Republic, but Israel now presents it as ‘an integral and vital part of the wider picture’. Indeed he suggests that Radical Enlightenment was ‘more internationally cohesive than the mainstream Enlightenment’ owing to the ‘intellectual backbone’ supplied by Spinozism. And with his astonishing command of sources in Spanish, Italian, French, Swedish and German, as well as English and Dutch, he has found traces of Spinozistic radicalism all over Europe, everywhere flourishing and everywhere persecuted, too. The Tractatus Theologico-Politicus was formally proscribed in the Dutch Republic in 1674, and in 1678 the provincial states imposed a ban on all Spinoza’s works. Spinozism was also caught up in attempts to halt the spread of Cartesianism in Sweden in 1689, while in England the Blasphemy Act of 1698 made it illegal to question Christ’s divinity or the doctrine of the Trinity, which automatically placed Spinoza beyond the law.

The fate of the brothers Koerbagh is typical of the dozens of fascinating stories collected in Israel’s often brilliant book. Johannes and Adriaen Koerbagh were born in the 1630s, sons of a prosperous ceramics manufacturer who died while they were children, leaving them with the means to organise their own education as they pleased. They both began in the philosophy faculty at Utrecht, and moved in their early twenties to the senior faculties at Leiden. It was at about that time that they made the acquaintance of Spinoza, who was no older than them but already celebrated as the precocious genius who kept his Bible on the same shelf as a copy of the Koran and, having been excommunicated from the Amsterdam synagogue, now earned a humble living as a lens grinder.

The brothers were also committed to the Puritan ideal of vernacular plain speaking, and in 1664 Adriaen published a dictionary of legal terms which promised to strip away the self-serving gibberish of the law and make every man his own lawyer. He also courted censure by openly living with a woman and their bastard child. Meanwhile his younger brother, Johannes, though registered as a trainee in the Reformed Church, publicly argued that there was no divine inspiration in the Bible and that God was not a person of any kind, but simply the ‘supreme being’. To avoid any possible misunderstanding he went on to ridicule the doctrine of the Trinity and denounce the superstitious practice of venerating Jesus. The Koerbaghs then decided to pool their talents to annoy by collaborating on a wordbook called the Bloemhof or ‘Garden of all kinds of loveliness without sorrow’. The purpose of the work, published pseudonymously in 1668, was to nurture the unassuming native flowers of the Dutch language and preserve them from the Latinate sophistications of all those who had a professional interest in confounding ordinary folk and swindling them out of their innate good sense. The book ranged boldly over medicine, law and philosophy (or rather ‘worldly wisdom’), but it was its treatment of theological terms that was most reckless. Angels, demons, witchcraft, divination and heresy all turned out to be terms that had been stolen from the people and emptied of vital reality. In the same way, according to the Bloemhof, miracles and the Trinity were impossible, ‘Reformed Religion’ was a misnomer because the Dutch church was as corrupt as ever, and Jesus was an ordinary man, indeed a bastard, though a fairly unusual one.

The brothers Koerbagh must have known that the authorities would not find it hard to trace the compilers of this defiantly illegal book. Adriaen fled Amsterdam under an assumed name, though he immediately started preparing another collaborative book for a printer in Utrecht. It was known as Een Ligt, or ‘A light shining in dark places’, and the printer got worried when he realised that it made the argument that scriptures, priests, revelations and churches are pointless because God is already wholly accessible to ordinary human experience. Johannes, who had stayed in Amsterdam, was immediately arrested, and with the help of a reward of 1500 guilders Adriaen was captured in Leiden and brought back to face trial. He was lucky enough to persuade the magistrates that his brother was innocent, while he himself got away with an unexpectedly lenient sentence: a 4000 guilder fine and ten years’ imprisonment in the Rasphuis followed by ten years’ banishment. The prison regime broke him within a few months, however, and he died in 1669 at the age of 37. Three years later Johannes, who had at last learned to keep his counsel, died too.

We can only be grateful to Israel for reconstructing this sad story, but when he goes on to describe it as ‘the first act of a drama soon to reverberate all over Europe’, we may feel that he is a little too eager to incorporate it in a grand historical tapestry. Of course we cannot really object when he says that Een Ligt – though suppressed so effectively that it was almost unknown till the 20th century – was ‘one of the first and, by any reckoning, one of the most far-reaching texts of the European Radical Enlightenment’. No one would have recognised the idea of ‘European Radical Enlightenment’ at the time, after all, so Israel is in no danger of colliding with contemporary evidence: it is his own theoretical construct and he can use it to mean more or less whatever he likes. On the other hand, he makes a debatable point when he recruits the Koerbaghs to the vanguard of a long philosophical revolution that was going to change Europe utterly. Before the revolution, as Israel sees it, there was the medieval world, ‘based on a largely shared core of faith, tradition and authority’; after it, a new civilisation where ‘everything, no matter how fundamental or deeply rooted, was questioned in the light of philosophical reason’. The brothers Koerbagh, in Israel’s argument, belong at the beginning of the ‘general process of rationalisation and secularisation . . . which rapidly overthrew theology’s age-old hegemony in the world of study’.

‘Age-old’ is not the sort of phrase you expect to find in the lexicon of an alert professional historian, and there is as much myth as rationality in Israel’s distinction between the theological Middle Ages and philosophical Modernity. He must know that medieval universities were dominated by their philosophical faculties and that no one could enter a theological faculty until they had spent a few years ingesting large doses of pagan philosophy in the form of Aristotle’s logic, ethics, physics and metaphysics. He must also be aware that, if the process of Enlightenment is to be defined in terms of respect for philosophical reason, then there is a case for naming Abelard and Duns Scotus, rather than Descartes and Spinoza, as its earliest pioneers. As for the story of ‘Radical’ Enlightenment, you could just as well start it with the burning of Bruno in Rome in 1600, or Vanini in 1619; and there are many bold publications – Gassendi’s reconstructions of Epicureanism, Winstanley’s Law of Freedom, or Hobbes’s Leviathan, for instance – that could easily be thought of as stealing a march on the valiant brothers Koerbagh.

But, of course, the periodisation game is not really about chronology at all, and debates about the dating of the Enlightenment turn on disagreements about the present rather than the past. Radical Enlightenment is marketed as a book about ‘today’: its publicity material refers to ‘ideas that led to the French Revolution and . . . made the world we know’ and ‘the most decisive shift in the history of ideas in modern times . . . a philosophical movement that still affects us today’. In effect Israel takes issue both with Kantians who see the essence of the present as intellectual autonomy, and with Hegelians who see it as deluded subjectivism. He is also dissenting from Gay’s grateful evocation of ‘freedom in its many forms’, and disagreeing with such sages as Berlin and Nicolson who warned us not to put too much trust in transcendent reason. For Israel it is the risky and raucous radicalism of the 17th century which, by helping to ‘lay the foundations of the modern world on the basis of equality, democracy, secular values and universality’, has put an end both to ‘religious dominance over education’ and to ‘man’s dominance over woman’.

Some of us might put our money on rather bleaker characterisations of the world we live in; but perhaps it would be best to stay out of the lottery altogether. After all there may be something wrong with the idea of epochs having a single ‘core’, ‘essence’ or ‘basis’, and there is certainly something to be said against all the definitions of the present age currently on offer. You don’t need to be a Marxist to question the presumption that we can simply set aside the history of class struggle and the forces of production, and that the only history we need in order to understand ourselves is the history of philosophy.

Of course a lot will depend on what you think philosophy is, and how you think its history should be told. Histories of war do not have to be written by soldiers or enthusiasts for pitched battles, after all, any more than political histories have to be written by politicians; so there need be nothing wrong with a history of philosophy written by a historian. Israel may not care to linger over the intense artistry of the Ethics, for example, but then he is concerned only with those elements of Spinoza’s work which flowed into what he calls the ‘potent intellectual undercurrent’ or the ‘powerful intellectual current’ of Radical Enlightenment. He is interested in Spinoza not as a thinker who can still unsettle any good reader, but as a public figure who discharged his historic tasks more than three centuries ago by standing ‘at the head of an underground radical philosophical movement rooted in the Netherlands’. Philosophically, Spinoza’s account of the relation between our bodies and our ideas of our bodies may be open to infinite reinterpretation; but historically it seems to be sufficient to label him a ‘materialist’ whose legacy became ‘one of the central planks of the European Enlightenment as a whole’. To anyone who wants to tarry in philosophical perplexity, Spinoza’s account of human nature and its relation to God is even more rich and strange; but Israel makes short work of reducing it to ‘a preoccupation with “natural man” which runs like a thread through the Radical Enlightenment from Spinoza . . . to Rousseau, and ultimately the militant, revolutionary egalitarianism of Robespierre and the Jacobins’.

Israel’s metaphors are not just for decoration: his story of ‘philosophy and the making of modernity’ would not hold together without its currents, roots, leaders, bases, movements and planks. But they give a peculiar spin to his history, making the intellectual and literary labours of individual philosophers appear entirely subservient to certain master plans of philosophical change that are somehow – who knows how? – immediately apparent to the historian. Of course it will sometimes be possible for historians to observe waves of opinion, fashion and taste as they propagate themselves, like infectious diseases, across populations and over generations. But when it comes to deliberately constructed works of science or art, historians need to understand what they are about if they are not to miss the point. And the same, you would have thought, might apply to works of philosophy: for example, to essays about such intrinsically elusive issues as whether everything is governed by universal mathematical principles, and if so whether our ordinary human concerns – our loves and principles and passions – are nothing but inane parochialisms that we project onto an indifferent universe, signifying nothing. Historians may assure us that these preoccupations belong to the Age of Enlightenment and that the argument has moved on since then. But that does not mean we can confine them to the past and treat them as lifeless relics of a bygone age. Most of us will never be able to prevent them from obtruding into our lives from time to time, with an inconvenient power to upset our intellectual peace. They are peculiarly unhistorical questions, in that whenever we confront them we have to start again from the beginning. They have the temporality not of historical epochs but of spots of time or recurrent moments of mental crisis.

‘Crisis’ is, as it happens, the word favoured by one of Israel’s great predecessors, the French historian Paul Hazard. He had no explicit notion of ‘Radical Enlightenment’, but as early as 1935 he was arguing that the High Enlightenment was only a secondary phenomenon, an aftershock following earlier philosophical earthquakes. ‘The great battle of ideas was already over by 1715, and even by 1700,’ he wrote: ‘the simple audacities of the Aufklärung and the époque des lumières pale into insignificance alongside the aggressive audacities of the Tractatus Theologico-Politicus and the vertiginous audacities of the Ethics.’ If history had ever produced a genuine novelty, it was the clear-eyed radicalism of Spinoza, which engendered the ‘resolve to look to the future rather than the past’ that has since permeated all departments of ‘everyday life’ and become the key to ‘our present epoch’. But Hazard took care to avoid implying that the significance of Spinoza’s writings could have been known in advance. To his 20th-century eye, he said, the ‘essential characteristic’ of the late 17th century was the indomitable courage with which its thinkers sought to ‘find their way to their unknown destiny’. The period struck him as suffused with a ‘dolorous beauty’, which he summed up by calling his book La Crise de la conscience européenne.

Israel, on the other hand, has no time for imponderables like crises of conscience or consciousness. A funny thing happens to exponents of doubt and intellectual devastation when they are summoned to the office of a thoroughly modern historian. They cease to be high-wire artists risking all for the sake of a little clarity, and become truculent defenders of miscellaneous dogmatic opinions. The characters in Israel’s Radical Enlightenment, from Spinoza to the brothers Koerbagh and from Descartes to the authors of the Trois imposteurs, are not the sort of people who would get caught short by a twinge of doubt or buffeted by the force of contrary arguments. They never wonder, pause, hesitate, backtrack or despair, and they are never shocked, surprised or delighted by any unexpected twists and turns in their own thinking. They have no ambition beyond making ‘propaganda’ for Radical Enlightenment. They know what they think, and in Israel’s favoured vocabulary, they simply ‘maintain’, ‘admonish’ and ‘aver’ – at their best they do it ‘unequivocably’. They behave as if philosophy were a kind of positional warfare or political horse-trading in which nothing matters except securing victory for your own side. In 1700, for example, they could see that the faction of Descartes was ‘strongly placed to win’, but then several big players ‘came out against Cartesianism’ and another ‘edged towards Newton’ so that things started looking bad for ‘the Cartesian camp’. No doubt they look pretty bad still; but beyond the thrills of the campaign, the mind-stopping issues cannot have gone away: they were troubling people then just as they are now. The date has nothing to do with it.