The eighteenth century was a productive time for philosophy. Driven by (and also driving) developments in politics, economics, art, science and religion, philosophy throughout Western Europe during the period from Descartes to Kant was able to advance on all fronts. This creative intellectual effort resulted in many of the ideas that a further two-hundred years of academic effort have been unable to surpass, although many have been somewhat refined. Indeed, the great metaphysical questions that boomed during the eighteenth century—relating to God, freedom, and morality—have attracted students to philosophy as an academic discipline ever since.

A major work on eighteenth century philosophy is therefore to be welcomed as an opportunity to allow philosophy to re-examine its roots. It is certainly about time. As the contributor T.J. Hochstrasser (London School of Economics) points out early on in this quite hefty two-volume encyclopaedia, there has been no major single-author survey of the Enlightenment since Peter Gay published his The Enlightenment: An Interpretation in the late 1960s. Could, therefore, The Cambridge History of Eighteenth Century Philosophy mark a further intellectual leap along the road to understanding this most important of periods in intellectual history?

An intellectual leap may well be the intention of the editor. In his introduction Knud Haakonssen (Professor of Intellectual History at the University of Sussex) makes explicit his desire to take a new look at the Enlightenment and to escape what he calls the ‘epistemological paradigm’ when analysing the philosophy of the time. This paradigm, which sees eighteenth century philosophy merely as an epistemological development in ideas from Descartes' Discourse on Method (1637) to Kant's Critique of Pure Reason (1781/1787), Haakonssen claims has hitherto held back our understanding of the epoch and was in fact largely a myth written into the history of philosophy by nineteenth century Kantian historians. For Haakonssen, epistemological thought was only one of several intellectual strands of the time, and the Cambridge History reflects this by attempting to present ideas—on human nature, theology, aesthetics, natural and moral philosophy—as they were seen at the time, regardless of whether these ideas were able to shed any useful light on epistemological problems. Admittedly, this approach by Haakonssen has been highly informative, as it has given the contributors free rein in selecting the aspects of philosophy they wish to discuss.

Part 1 of the book, entitled ‘The Concept of Eighteenth-Century Philosophy’, is particularly interesting, as contributor after contributor reminds us of the progressivism that imbued philosophical thinking at the time: Carl Henrik Koch (Københavns Universitet) informs us, for instance, that Thomasius (1655–1728) was one of the first philosophers to lecture in his native German, implying that the communication of ideas is integral to their development; elsewhere, Hochstrasser quotes from Voltaire (1694–1778)—“One day is enough for a wise man to get to know the duties of man”—in showing how philosophy in the eighteenth century was seen as nothing if not accessible, in contrast to the mysteries of both science and religion.

At the same time, however, this reluctance to bring philosophical ideas under a ‘paradigm’ perhaps explains why this Cambridge History also has an air of indifference to it about where the century was heading. Many ideas are introduced by contributors without comment as to whether they are right or wrong, or even better or worse than the preceding ideas. The hope naturally is that the ideas of the eighteenth century are given space to express themselves, without the biased voice of the historian drowning them out. This is a noble sentiment, but the problem with it is that it does not assist us in forming an appreciation of old ideas today: in judging the ideas of the past, it often helps to know who their present-day enemies and allies are.

So, for instance, Hochstrasser's chapter on eighteenth century European philosophical institutions gives an interesting insight into how the free-thinking academies grew up in the shadows of the hide-bound universities, which (with the exception of Edinburgh and Glasgow) were still wrapped up in scholasticism, and not given to thinking about how problems related to the world outside. Indeed, throughout the century a great many of the institutions in which philosophy was discussed were opening up, and inviting wider participation. So two-hundred and fifty years ago it was better to study under the patronage of a Prussian Elector than from within the confines of an Oxbridge college. But Hochstrasser presents this development in a sober, matter-of-fact tone, which invites the reader to either take it or leave it, not to embrace it. After describing this opening up of institutions he does not link it to the increasing accessibility of philosophical knowledge itself, a linking that would surely show the institutional change to be a positive development. He might fairly easily have shown how Descartes arrived at his conclusions through introspection, whereas one-hundred and fifty years later Kant attempted to establish objective and universal criteria for knowledge, and thereby a firmer foundation for future developments. But no. It is perhaps this matter-of-factness that is the Cambridge History's ultimate shortcoming, and it certainly gives the book a much less enthusiastic tone than Gay's 1960s benchmark.

Given the correlation between the development of philosophy and the development of the institutions in which it was studied, it is worth asking whether it is necessarily wise to dispense with the epistemological paradigm as a method of understanding the entire breadth of eighteenth century philosophy. Of course, we should not close ourselves off from developments in other branches of philosophy. But even during its reign the epistemological paradigm hardly rode roughshod over these other branches. Indeed, the drive to question our knowledge on epistemological grounds led English, Scottish, French and German philosophers into the realms of politics, history, morality and art, wherein they developed the material that lay to hand and left us with the autonomous disciplines we have today. Without the epistemological challenge thrown down by scientific developments in the seventeenth century, all of these other realms would not have benefited from the philosophical reaction to Cartesian dualism—an idea that expressed both the confusion stemming from science's ‘decentring’ of man and the power to overcome that confusion through further scientific work. So we have to thank, among others, Giambattista Vico (1668–1744) for developments in historiography, David Hume (1711–1776) for developments in religion and historiography, Jean-Jacques Rousseau (1712–1778) for development in politics, and Immanuel Kant (1724–1804) for developments in morality and aesthetics. But none of these would have emerged had there not been a general epistemological reaction to Cartesian dualism.

This reaction applied especially to the development of moral philosophy. In the early part of the eighteenth century, when Bernard de Mandeville (1670–1733) wrote The Fable of the Bees, he was condemned by those who saw (rightly) that this was an attack on the very idea of man's higher moral attributes. Yet those who condemned him struggled to found those same higher attributes on anything more sophisticated than nature (or God, the author of nature). So in their chapter on ‘The Foundations of Morality’, David Fate Norton (McGill University) and Manfred Kuehn (Boston University) show how Francis Hutcheson (1694–1746) argued that man is genuinely virtuous, but that his (man's) virtue is only really a product of nature. Hutcheson may talk of human nature, but there is a definite hint of Mother Nature about it, as we find, according to Hutcheson, that in our moral judgements we are able to distinguish good from bad “without training or indoctrination”, i.e. before we have fully entered human society. Hutcheson himself was soon challenged on this point, and accused of reducing morality to biology.

The first philosophers to advance beyond this impasse, the first to overcome the dilemma in moral philosophy which either denied virtue or held it up as God given, were Rousseau and Kant. Norton and Kuehn claim that most of the French philosophes “remained ultimately within the [man-as-egoist] framework of the ideas of Hobbes and Mandeville”. As a result, “they cannot be said to have contributed anything substantially original to the discussions of the foundations of morality”. The exception to this was Rousseau, whose Discourse on the Origin of Inequality (1755) contrasted man's state of nature with the corrupting influence of society, and which therefore offered society as a middle way through the egoist-theological dilemma. Greater than the individual yet the creation of man, society could be used to explain the conflicting moral tendencies in man without recourse to God. The work done by Rousseau and others in elaborating social forces meant that, for the first time ever, moral philosophy had an independent foundation, and was no longer merely a branch of theology.

Kant, who admired the work of Rousseau, was able to develop moral philosophy further, and his Critique of Practical Reason (1788), which outlined the autonomy of morality, “changed the discussion of the foundations of morals forever”. Norton and Kuehn explain their basis for this claim by showing how Kant rejected any theory that rooted morality in nature or in any form of sensual pleasure, and instead insisted that morality was founded on a priori principles of reason, such that “the maxim of our action can become a universal law”.

Unfortunately, while Norton and Kuehn acknowledge that Kant's moral principles were neither theological nor natural, they see this as something of a flaw in his method. Kant's highly original foundation for morality, based on human reason and the assumption of human freedom, is dismissed as neither one thing nor another. They liken his a priori categorical imperatives to Plato's ideals, and end by claiming that, “In his own way, Kant substituted faith for knowledge”, suggesting that Kant was more a priest than a philosopher, and failing to impart to us any sense of the revolutionary implications of his philosophy.

Perhaps a book more committed to the epistemological paradigm would not have left the assessment of Kant's contribution to moral philosophy at such a loose end. The truth is, in developing morality Kant was able to develop his epistemological ideas along with it, by enlarging the concept of the noumenal which he had earlier outlined in his Critique of Pure Reason (1781/87). By the close of this first Critique the noumenal was seen as merely the unknowable cause of the phenomenal; in the Critique of Practical Reason Kant begins to show how the noumenal object correlates with an objective consciousness. We may not be able to directly experience it, but we can know something of the thing that underlies the phenomenal cluster, and that thing turns out to be our own moral intention concerning our relation to the object. In other words, beyond the properties of an object that we can experience, there always lies a property of ourselves, namely, what we would like to do with that object. In the 1960s, for instance, NASA's (and thereby mankind's) knowledge of the solar system was guided and enhanced by its intention to land on the Moon. All human knowledge turns out to be this potent mixture of fact and value, and the two interact with and change each other as knowledge progresses.

This is where the epistemological paradigm can be so useful, shedding light on all other areas of philosophy, not just on narrow questions of rationalism vs. empiricism. The guiding hand of an epistemological editorial enthusiast might therefore have been useful here in developing this book into the unified study so deserved of the eighteenth century's great thinkers. As things stand, however, this Cambridge History must remain at the level of the eclectic appreciation, and take satisfaction in its bringing together of a wealth of material that could encourage future philosophy students to bring some of these all important strands together.