To talk favourably of the Enlightenment has become something of a taboo in recent years. Some writers deny its existence, while others present it as a reactionary development. It is therefore refreshing to find a serious treatment of the intellectual trends of the late 17th and early 18th century that is not afraid to identify the Enlightenment as a progressive movement, which is associated with the rise of rational thought and a belief in equality and democracy.
Jonathan Israel’s latest book is an important contribution to the history of ideas. He is eminently qualified for the task. His previous works include The Dutch Republic: Its Rise, Greatness, and Fall, 1477-1806  which allowed him to survey the period over a broader date range from the point of view of Holland—a country vital to the early history of the Enlightenment, as he demonstrates in his present book. If the Dutch Republic was encyclopaedic in its breadth of scholarship, the Radical Enlightenment is no less erudite.
In great measure, the book is a dialogue with the Belgian historian Paul Hazard. After seventy years, Hazard’s book The European Mind, 1680-1715 remains one of the few general studies of the early Enlightenment. Israel develops Hazard’s conception of a crisis of the European mind which, although “born in the seventeenth century was destined to leave its impress on virtually the whole of the eighteenth century.” 
With some justification, Israel situates the crisis a little earlier than Hazard placed it. Hazard centred the crisis on the Revocation of the Edict of Nantes in 1685 , which forced French Huguenot refugees into Holland and England, where they played a vital role in disseminating the new ideas that had been developed in France. Israel argues that in England and the Dutch Republic, the challenge to the old intellectual order can be dated to the mid 17th century, between 1650-1680.
Israel’s thesis is that the Enlightenment must be understood as an international phenomenon, rather than as being made up of many separate national currents. He argues that the republicans, materialists and atheists, whom some historians have identified as the Radical Enlightenment, are not peripheral figures but were central to the development of modern thought. This means that he accords far more importance to the Dutch materialist philosopher Spinoza (1632-77) than is customary.
Rather than being seen as an isolated figure, Spinoza is given his rightful place as a pervasive influence on the Enlightenment. This reappraisal of Spinoza’s impact follows Stephen Nadler’s recent biography Spinoza, a Life, which is part of renewed interest in this neglected philosopher over the last decade . Nadler’s book was the first complete biography of Spinoza and drew extensively on archival sources to place him in historical context. It locates Spinoza as a member of the Dutch Jewish community, and, after his excommunication, as part of a group of freethinkers from a variety of religious backgrounds, who corresponded and discussed with the leading international scientists and mathematicians of the day.
It is in tracing the influence of this personally retiring, but by no means isolated philosopher that Israel makes his distinctive contribution to the history of the period. He shows the way in which Spinoza influenced Enlightenment thought throughout Europe. While only the most radical thinkers accepted his ideas, even the more conservative, who rejected Spinoza’s atheism and materialism, could not avoid having to answer him.
Robert Boyle (1627-91), the English natural philosopher and chemist, discussed Spinoza’s ideas with Henry Oldenburg (c1620-77), secretary of the Royal Society, and wrote several papers defending miracles, the resurrection and divine providence in response to this challenge. Pierre Bayle (1647-1706), who played a pivotal role in the early Enlightenment, did much to publicise Spinoza’s philosophy.
The English philosopher John Locke (1632-1704) may have had connections with followers of Spinoza, while he was living as an exile in Rotterdam. Although they were banned, Locke certainly had all Spinoza’s books in his library. By the 1690s, Spinoza’s ideas could be found in all the bookshops, and even polemics against him served only to spread the intellectual contagion.
Israel is particularly good dealing with the impact of censorship and the extent of the trade in banned books, for which Holland was a centre. Even in England, where censorship was comparatively light, the Blasphemy Act of 1698  had a repressive influence on the development of ideas. Not only overtly atheistic attacks on religion fell foul of it, but even some attempts to defend Christianity.
Censorship was a far more present threat in France. Nonetheless, banned literature found its way into the country. The physicist Christiaan Huygens (1629-95) smuggled copies of Spinoza’s books into France concealed in the baggage of the Dutch ambassador. In 1705, the Paris police discovered a network of depots in a number of aristocratic town houses where crates of banned books had been sent from Holland. Educated servants in aristocratic households seem to have played an important part in the clandestine book trade.
Israel corrects the impression created by the historian Robert Darnton, who argues that much of the banned literature was erotic trash, and that the police of Louis XIV’s France were more concerned to ban this than the writings of serious philosophers, who were considered no threat to the regime. Israel shows that alongside the erotica, the illicit book stores contained the works of Bayle, Spinoza and other philosophers.
According to Israel, Spinoza became “the supreme philosophical bogeyman of Early Enlightenment Europe”, and was the “source for a systematic redefinition of man, cosmology, politics, social hierarchy, sexuality and ethics.” With his theory that the universe consists of a single substance of which thought and “extent” (a concept derived from the scientific understanding of the day of the geometrical properties of matter) are attributes, he provides the basis for the materialism of La Mettrie (1709-51), Diderot (1713-84), Helvétius (1715-71) and d’Holbach (1723-89).
Israel offers a clear, concise and sympathetic account of Spinoza’s philosophy. He explains that Spinoza’s primary contribution to the Enlightenment was to bring together all the strands of atheistic thought from ancient, oriental and modern philosophy into a coherent system. Even though Spinoza still wrote about God, he identified God with Nature. He was not, however, a pantheist who thought of God as a spiritual force animating the material world.
Spinoza developed his ideas in the process of a critique of the philosophy of Descartes (1596-1650). Unlike Descartes, with his famous dictum “I think therefore I am,” for whom the starting point is thought, Spinoza begins with substance. Spinoza argues that all that exists is one infinite substance; God does not exist outside of the world as a prime mover; substance is the cause of itself; there is no ideal world of spirit or thought; even God is substance. His critics declared this to be the “foundation of his whole impious doctrine.”
Spinoza’s system was a deterministic one, controlled by the laws of nature. He argued that men believe themselves to be free because they are conscious of their desires, but do not perceive “those causes by which they are disposed to wanting and willing.” They imagine that a divine being exists to order the world in accordance with their needs, to reward the pious and punish the wicked. “Anyone who seeks the natural causes of what most men consider to be supernaturally devised, and to ‘understand natural things and not to wonder at them like a fool’, is generally condemned as a heretic.”
Israel recognises that Spinoza’s contention that “the order and connection of ideas is the same as the order and connection of things” is “a difficult and challenging assertion which the modern reader is hardly likely to accept without question.” It is therefore to his credit that he does not shrink from expounding it, although it has become one of the most controversial features of Spinoza’s philosophy, because it is central to a materialist understanding of the world.
Spinoza rejected Descartes’ dualism, the split between mind and body. For Spinoza, thought is an attribute of substance. Man’s thinking, just as much as his bodily nature, are properties of substance. Thought parallels the phenomena of the corporeal world. “The two chains of phenomena are conceptually but not actually separate,” as Israel explains. They are “distinct aspects of one and the same reality.”
Liberty and equality
It is one of the great strengths of Israel’s book that he shows how Spinoza’s progressive philosophical ideas were associated with concepts of political liberty and social equality. While the English philosopher Hobbes (1588-1679) had developed a materialist philosophy, he remained a firm supporter of absolute monarchy. Spinoza, by contrast, equates liberty and reason, advocates government based on common consent, and favours a democratic republic over monarchy. Such a society, Spinoza envisaged, would allow freedom of thought and speech and would recognise that the natural equality of men must be reflected in the political system.
In his biography, Nadler argues for a connection between Spinoza and Jan de Witt, who headed the Dutch republican government. He notes that de Witt’s enemies accused him of protecting Spinoza, and that Spinoza wanted to make a protest when de Witt was murdered by an anti-republican mob in 1672. Once de Witt was dead the generally tolerant intellectual atmosphere in Holland that had allowed Spinoza to flourish came to an end, Nadler argues.
Israel does not accept that any personal connection existed between Spinoza and de Witt, but nonetheless agrees that Spinoza was by no means remote from the politics of his own day. After de Witt’s regime was overthrown, the situation in Holland became more repressive and more difficult for Spinoza, whose theory that there was no divine punishment for sinners or reward for the virtuous was regarded as a seditious doctrine. According to Israel, the Dutch authorities watched him carefully in the years before his death in 1677, with the result that “Spinoza spent the last eighteen months of his life in virtual seclusion in his lodgings.”
In the repressive atmosphere of the late 17th century, Spinoza’s ideas were inevitably forced underground, but Israel unequivocally identifies the upheaval in thought of which Spinoza is a part as the ideological prelude to the French Revolution of 1789. The Enlightenment was “a revolution of the mind—that had matured and seeped its way through large sections of society over a long period before the onset of the revolution in actuality.”
The book does have two serious faults. The first is that Israel refuses to accord John Locke the important role he deserves in Enlightenment thought. He regards Locke as a spokesman for a moderate Enlightenment, whose ideas were taken up to counter those of Spinoza and the more radical philosophers. This seriously underestimates Locke’s contribution to the development of materialist thought, through his theory that man has no innate ideas but derives all his conceptions from sense impressions. Locke’s sensualism suggested materialist conclusions to the French philosophers of the 18th century and contributed to their ideas, just as Spinoza’s philosophy did. It would be entirely one-sided to exclude him in favour of Spinoza.
In setting up Locke against Spinoza, Israel is making an unnecessary concession to those who want to deny that the Enlightenment played a progressive historical role. As the title of his book indicates, he accepts the division between a radical Enlightenment represented by figures such as Spinoza and moderate mainstream Enlightenment typified by Locke and Sir Isaac Newton (1642-1727).
This distinction has been made by historians such as Margaret Jacob, who identifies the radical Enlightenment as the work of “intellectual dissenters, men, and possibly a very few women, often with a refugee background, who could not share the willingness of the major philosophes like Voltaire and d’Alembert, or liberal churchmen like the Newtonians in England, to put their faith in enlightened monarchy.”
Essentially this approach is prepared to accept the criticisms that post-modernist theorists have made of the Enlightenment, while making an exception for a few outstanding individuals like Spinoza, or secondary characters that do not usually appear in the histories of philosophy. Israel recognises the inadequacy of such a treatment because it would relegate Spinoza to the periphery. He knows that Spinoza is far more central to the development of modern European thought than this approach would allow, but he still wants to retain the artificial moderate/mainstream or radical/conservative distinction. This is an unhistorical categorisation, which does not place these figures in their historical context and refuses to recognise that even the greatest thinkers of the period remained men of their time.
It is seldom easy to distinguish the radical from the moderate Enlightenment thinker. Take John Locke for example. While Locke can be considered politically conservative in welcoming the compromise settlement that brought the Dutch monarch William of Orange to the English throne in 1688, his political theories have a far more revolutionary side to them, in that he explicitly defends the right of resistance against an unjust government and is an advocate of equality.
It is not only in the realm of ideas that Locke breaks through any simplistic categorisation as a conservative. He spent much of his career as a political conspirator, actively working to overthrow the government of Charles II of England. When these plans failed he became a refugee in Holland, kept under surveillance by English spies. Among his political collaborators were artisans, Levellers, former Cromwellian soldiers and republicans. However radical these men’s political credentials may have been, those that survived accepted posts under William of Orange, as Locke did, because the revolutionary upsurge of the mid-century was spent.
Locke reflected the interests of a class that, after 40 years of turbulence, wanted peace and stability. But his contribution to future revolutionary movements was to codify the principles of the English revolution in such a way that they became part of the basic political vocabulary of men of a later generation such as Thomas Paine, who used Locke extensively to compose the Rights of Man, and Thomas Jefferson, who took whole phrases from Locke in drafting the American Declaration of Independence.
The book’s second failing is the more serious. At no point does Israel mention Marxism, even when it would make his book clearer to do so. Spinoza may have died two centuries before Marx, but it is difficult to discuss his ideas without at least raising the issue of Marxism, because Spinoza’s materialist outlook has become so closely identified with it.
This is what makes Spinoza so contentious today. He was not only a bogeyman in his own time, but continued to be one in the 20th century. The philosopher and pacifist Bertrand Russell (1872-1970) found it necessary to attempt to discredit Spinoza, claiming that his philosophy was an “outmoded” point of view “which neither science nor philosophy can nowadays accept.” When the German Social Democrat Eduard Bernstein (1850-1932) wanted to undermine Marxism, he felt it necessary to attack Spinoza’s materialist understanding of the representation of the external world in thought.
In defending the Marxist tradition against Bernstein, the Russian Marxist G. V. Plekhanov (1857-1918) recognised the debt Marxism owed to Spinoza. “Present day materialism,” he wrote “is a Spinozism that has become more or less aware of itself.”. He recalled how in 1889 he had visited Frederick Engels in London and discussed Spinoza’s philosophy. Plekhanov asked, “‘So you think... old Spinoza was right when he said that thought and extent are two attributes of one and the same substance?’ ‘Of course,’ Engels replied, ‘Old Spinoza was quite right.’”.
Spinoza’s system, Israel writes, “imparted shape, order and unity to the entire tradition of radical thought,” but for Israel that tradition stops with the French revolution; he does not follow it through to Marxism. In cutting short his own argument in this way, Israel is paying deference to an academic audience that is hostile to Marxism and any serious discussion of it.
 Jonathan Israel, The Dutch Republic: Its Rise, Greatness, and Fall, 1477-1806, Oxford University Press, 1995, ISBN 0-19-820734-4
 Paul Hazard, The European Mind, 1680-1715, Fordham University Press, 1990, ISBN 0-8232-1274-2
 The Edict of Nantes, which ended the 8th French Religious War in 1598, allowed French Protestants [Huguenots] freedom of conscience and the right to practice their religion. When Louis XIV revoked it many of them were forced to leave the country.
 Stephen Nadler, Spinoza, a Life, Cambridge University Press, 1999, ISBN 0 521 55210 9
 Censorship had been lifted during the English Revolution of the 1640s. The Blasphemy Act of 1698 was one of a series of measures to control the spread of religious dissent, atheism, materialism and revolutionary ideas.
 Margaret Jacob, The Radical Enlightenment: Pantheists, Freemasons and Republicans, Allen and Unwin, 1981, ISBN 0-04-901029-8
 E. V. Ilyenkov, Dialectical Logic, Essays on its History and Theory, Progress Publishers, 1977 p42; (see also: http://bdsweb.tripod.com/en/104.htm)
 G.V. Plekhanov, Selected Philosophical Works vol. II, Progress Publishers, p320
 Ibid p339
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