The story of this book begins with a hoax. For some years, we have been surprised and distressed by the intellectual trends in certain parts of American academia. Vast sectors of the humanities and the social sciences seem to have adopted a philosophy that we shall call for want of a better term, ‘postmodernism’: an intellectual current characterized by the more-or-less explicit rejection of the rationalist tradition of the Enlightenment, by theoretical discourses disconnected from any empirical test, and by a cognitive and cultural relativism that regards science as nothing more than a ‘narration’, a ‘myth’ or a social construction among many others.

To respond to this phenomenon, one of us (Sokal) decided to try an unorthodox (and admittedly uncontrolled) experiment: submit to a fashionable American cultural-studies journal, Social Text, a parody of the type of work that has proliferated in recent years, to see whether they would publish it. The article, entitled ‘Transgressing the boundaries: Toward a transformative hermeneutics of quantum gravity’, is brimming with absurdities and blatant non sequiturs. In addition, it assert an extreme form of cognitive relativism: after mocking the old-fashioned ‘dogma’ that ‘there exists an external world, whose properties are independent of any individual human being and indeed of humanity as a whole’, it proclaims categorically that ‘physical "reality", no less than social "reality", is at bottom a social and linguistic construct’. By series of stunning leaps of logic, it arrives at the conclusion that ‘the pi of Euclid and the G of Newton, formerly thought to be constant and universal, are now perceived in their ineluctable historicity’. The rest is in the same vein.

And yet, the article was accepted and published. Worse, it was published in a special issue of Social Text devoted to rebutting the criticisms levelled against postmodernism and social constructivism by several distinguished scientists. For the editors of Social Text, it was hard to imagine a more radical way of shooting themselves in the foot.

Over the past two decades, much ink has been spilled about postmodernism, an intellectual current that is supposed to have replaced modern rationalist thought. However, the term ‘postmodernism’ covers an ill-defined galaxy of ideas - ranging from art and architecture to the social sciences and philosophy - and we have no wish to discuss most of these areas. Our focus is limited to certain intellectual aspects of postmodernism that have had an impact on the humanities and the social sciences: a fascination with obscure discourses; an epistemic relativism linked to a generalized scepticism towards modern science; an excessive interest in subjective beliefs independently of their truth or falsity; an emphasis on discourse and language as opposed to the facts to which those discourses refer (or, worse, the rejection of the very idea that facts exist or that one may refer to them).

By no means do we wish to inhibit interaction between the mathematico-physical sciences and the human sciences; rather, our aim is to emphasize some preconditions we see as necessary for a real dialogue:

The natural sciences are not a mere reservoir of metaphors ready to be used in the human sciences. Non-scientists may be tempted to isolate from a scientific theory some general ‘themes’ that can be summarized in few words such as ‘uncertainty’, ‘discontinuity’, ‘chaos’ or ‘nonlinearity’ and then analysed in a purely verbal manner but scientific theories are not like novels; in a scientific context these words have specific meanings, which differ in subtle but crucial ways from their everyday meanings, and which can only be understood within a complex web of theory and experiment.

The social sciences have their own problems and their own methods; they are not obliged to follow each ‘paradigm shift’ (be it real or imaginary) in physics or biology. For example, although the laws of physics at the atomic level are expressed today in a probabilistic language, deterministic theories can nevertheless be valid (to a very good approximation) at other levels, for example in fluid mechanics or even possibly (and yet more approximately) for certain social or economic phenomena.

Moreover, there are so many phenomena, even in physics, that are imperfectly understood, at least for the time being, that there is no reason to try to imitate the natural sciences when dealing with complex human problems.

If the human sciences want to benefit from the undeniable successes of the natural sciences, they need not do so by directly extrapolating technical scientific concepts. Instead, they could get some inspiration from the best of the natural sciences’ methodological principles, starting with this one: to evaluate the validity of a proposition of the basis on the facts and reasoning supporting it, without regard to the personal qualities or social status of its advocates or detractors.

If one wants to contribute to science, be it natural or social, one must abandon radical doubts concerning the viability of logic or the possibility of knowing the world through observation and/or experiment. Of course, one can always have doubts about a specific theory. But general sceptical arguments put forward to support those doubts are irrelevant, precisely because of their generality.

We have seen in this book numerous ambiguous texts that can be interpreted in two different ways: ... the radical interpretation can serve to attract relatively inexperienced listeners or readers; and if the absurdity of this version is exposed, the author can always defend himself by claiming to have been misunderstood, and retreat to the innocuous interpretation.

What is new and curious about postmodernism is that it is an anti-rationalist form of thought that has seduced part of the left. We shall try here to analyse how this sociological link came to be, and to explain why it is due, in our opinion, to a number of conceptual confusions. We shall limit ourselves mainly to the situation in the United States, where the link between postmodernism and some tendencies on the political left are particularly clear.

The existence of such a link between postmodernism and the left constitutes, prima facie, a serious paradox. For most of the past two centuries, the left has been identified with science and against obscurantism, believing that rational thought and the fearless analysis of objective reality (both natural and social) are incisive tools for combating the mystifications promoted by the powerful – not to mention being desirable human ends in their own right. And yet, over the past two decades, a large number of ‘progressive’ or ‘leftist’ academic humanists and social scientists (though virtually no natural scientists, whatever their political views) have turned away from this Enlightenment legacy and – bolstered by French imports such as deconstruction as well as by home-grown doctrines like feminist standpoint epistemology- have embraced one or another version of epistemic relativism. Our aim here is to understand the cause of this historical volte-face.

We shall distinguish below three types of intellectual sources linked to the emergence of postmodernism within the political left.

The 1960s and 1970s saw the rise of new social movements- the black liberation movement, the feminist movement and the gay-rights movement, among others - struggling against forms of oppression that had largely been underestimated by the traditional political left. More recently, some tendencies within these movements have concluded that postmodernism, in one form or another, is the philosophy most suited to their aspirations.

Another source of postmodern ideas is the desperate situation and general disorientation of the left, a situation that appears to be unique in its history. The communist regimes have collapsed ; the social-democratic parties, where they remain in power, apply watered-down neo-liberal policies; and the Third World movements that led their countries to independence have, in most cases, abandoned any attempt at autonomous development. In short, the harshest form of ‘free market’ capitalism seems to have become the implacable reality for the foreseeable future. Never before have the ideals of justice and equality seemed so utopian.

... it is easy to understand that it generates a kind of discouragement that expresses itself in part in postmodernism.

In this atmosphere of general discouragement, it is tempting to attack something that is sufficiently linked to the powers-that-be so as not appear very sympathetic, but sufficiently weak to be a more-or-less accessible target (since the concentration of power and money are beyond reach). Science fulfils these conditions, and this partly explains the attacks against it. In order to analyse these attacks, it is crucial to distinguish at least four different senses of the word ‘science’: an intellectual endeavour aimed at a rational understanding of the world; a collection of accepted theoretical and experimental ideas; a social community with particular mores, institutions and links to the larger society; and, finally, applied science and technology (with which science is often confused). All too frequently, valid critiques of ‘science’, understood in one of these senses, are taken to be arguments against science in a different sense. Thus, it is undeniable that science, as a social institution, is linked to political, economic and military power, and that the social role played by scientists is often pernicious. It is also true that technology has mixed results – sometimes disastrous ones – and that it rarely yields the miracle solutions that its most fervent advocates regularly promise. Finally, science, considered as a body of knowledge, is always fallible, and scientists’ errors are sometimes due to all sorts of social, political, philosophical or religious prejudices. We are in favour of reasonable criticisms of science understood in all these senses. In particular, the critiques of science viewed as a body of knowledge – at least those that are most convincing - follow, in general, a standard pattern: First one shows, using conventional scientific arguments, why the research in question is flawed according to the ordinary canons of good science; then, and only then, one attempts to explain how the researchers’ social prejudices (which may well have been unconscious) led them to violate these canons. One may be tempted to jump directly to the second step, but the critique then loses much of its force.

Unfortunately, some critiques go beyond attacking the worst aspects of science (militarism, sexism, etc.) and attack it best aspects: the attempt at rationally understanding the world, and the scientific method, understood broadly as a respect for empirical evidence and for logic. It is naive to believe that it is not the rational attitude itself that is really challenged by postmodernism. Moreover, this aspect is an easy target, because any attack on rationality can find a host of allies: all those who believe in superstitions, be they traditional ones (e.g. religious fundamentalism) or New Age. If one adds to that a facile confusion between science and technology, one arrives at a struggle that is relatively popular, though not particularly progressive.

Postmodernism has three principal negative effects: a waste of time in the human sciences, a cultural confusion that favours obscurantism, and a weakening of the political left.

First of all , postmodern discourse, exemplified by the texts we quote, functions in part as a dead end in which some sectors of the humanities and social sciences have got lost. No research, whether on the natural or the social world, can progress on a basis that is both conceptually confused and radically detached from empirical evidence.

What is worse, in our opinion, is the adverse effect that abandoning clear thinking and clear writing has on teaching and culture. Students learn to repeat and to embellish discourses that they only barely understand. They can even, if they are lucky, make an academic career out of it by becoming expert in the manipulation of an erudite jargon. After all, one of us managed, after only three months of study, to master the postmodern lingo well enough to publish an article in a prestigious journal. As commentator Katha Pollitt astutely noted, ‘the comedy of the Sokal incident is that it suggests that event the postmodernists don’t really understand one another’s writing and make their way through the text by moving from one familiar name or notion to the next like a frog jumping across a murky pond by way of lily pads.

These two attitudes are, of course, conceptually distinct; one can be adopted with or without the other. However, they are indirectly linked: if anything, or almost anything, can be read into the content of scientific discourse, then why should anyone take science seriously as an objective account of the world? Conversely, if one adopts a relativist philosophy, then arbitrary comments on scientific theories become legitimate. Relativism and sloppiness are therefore mutually reinforcing.

But the most serious cultural consequences of relativism come from its application to the social sciences. The British historian Eric Hobsbawm has eloquently decried

"The rise of ‘postmodernist’ intellectual fashions in Western universities, particularly in departments of literature and anthropology, which imply that all ‘facts’ claming objective existence are simply intellectual constructions. In short, that there is no clear difference between fact and fiction. But there is, and for historians, even for the most militantly antipositivist ones among us, the ability to distinguish between the two is absolutely fundamental."

(Hobswam, The new trend to history, 1993, reprinted in On History.)

Hobsbawm goes on to show how rigorous historical work can refute the fictions propounded by reactionary nationalists in India, Israel, the Balans and elsewhere, and how the postmodernist attitude disarms us in the face of these threats.

At a time when superstitions, obscurantism and nationalist and religious fanaticism are spreading in many parts of the world - including the ‘developed’ West - it is irresponsible, to say the least, to treat with such casualness what has historically been the principal defense against these follies, namely a rational vision of the world. It is doubtless not the intention of postmodernist authors to favour obscurantism, but it is an inevitable consequence of their approach.

Finally, for all those of us who identify with the political left, postmodernism has specific negative consequences. First of all, the extreme focus on language and the elitism linked to the use of a pretentious jargon contribute to enclosing intellectuals in sterile debates and to isolating them from social movements taking place outside their ivory tower. When progressive students arriving on American campuses learn that the most radical idea (even politically) is to adopt a thoroughly sceptical attitude and to immerse oneself completely in textual analysis, their energy – which could be fruitfully employed in research and organizing – is squandered. Second, the persistence of confused ideas and obscure discourses in some parts of the left tends to discredit the entire left; and the right does not pass up the opportunity to exploit this connection demagogically.

It seems to us that postmodernism, whatever usefulness it originally had as a corrective to hardened orthodoxies, has lived this out and is now running its natural course.