The poet Robert Frost once described a liberal as someone unable to take his own side in an argument. Today it often seems that it's not just liberals who can't take their own side - it's almost an expression of the zeitgeist. Ours is an age in which few things seem to raise the hackles more than intellectual certainty or political decisiveness. It is in that context that we need to understand the debate about relativism.
In one sense, the debate about relativism might seem old hat - an academic spat, that raged fast and furious through the 90s, but which now appears to have burnt itself out and, in any case, has no real bearing outside the academy. I want to suggest, to the contrary, that relativism is so embedded in our lives that we often don't recognise it as such. The way we think of issues such as pluralism or tolerance, our understanding of personal identity, our attitudes to science - all are deeply shaped by the relativist outlook.
At the heart of relativism is the belief that there is no such thing as a universal truth, only a variety of conflicting truths, each of which may be regarded as valid. And that many such beliefs and values are incommensurate - not just incompatible, but incomparable, because there is no common language we can use to compare the one with the other.
The consequence of this approach has been both to undermine the value of knowledge and to narrow the scope of intellectual and political debate.
Science, for instance, is increasingly seen in some quarters as just another way of understanding the world. As Richard Rorty has put it, 'Scientists invent descriptions of the world, which are useful for purposes of predicting and controling what happens, just as poets and political thinkers invent descriptions of it for other purposes.' But no description, he argues, provides an accurate representation of the world.
It's true that science is not the only means through which to understand the world. But neither is science just another perspective. An argument such as Rorty's helps blur the distinction between fact and belief. It's a blurring that lies at the heart of many contemporary disputes about science.
Take, for instance, the debate about Kennewick Man. Here, the scientific study of an ancient skeleton has been held up for nearly a decade because of fears that such studies might undermine traditional Native American views of their origins, and their own sense of identity and being.
Or consider the debate over Creationism. Creationists now argue that evolutionary theory is just one way of understanding humanity's biological past, and one that is neither better nor worse, just different, to the account given in Genesis. So children should be taught both accounts as incommensurate truths about the world.
The blurring of fact and belief is also at the heart of such controversies as those over GM foods or the MMR vaccine. For what we see in these debates is the promotion of the idea that how one feels about an issue matters as much as what may be factually true. It's an argument that can only open the way to irrationalism and quackery.
Relativism undermines intellectual debate in a broader sense too. One legacy of relativism is that we've come to view pluralism not as a description but as a prescription. No one disputes that different people have different views that they often take to be truths. But we can view such pluralism as a precondition for debate - without a clash of views there can be no debate. Or we can view it, as relativists often do, as condition that makes debate either impossible or destructive. Impossible because the different views are incommensurate. Destructive because robust debate is seen as undermining the conditions for tolerance and pluralism. I've lost count of the number of times I’ve been prevented by both newspaper and radio editors from quoting from the Satanic Verses because it causes offence to Muslim believers. Either way the consequence has been to close down debate rather than open it up.
One final point. The production of knowledge is always historically, culturally, socially situated. But the situatedness of knowledge does not make it valid only in that particular context. It's a point that often forgotten by both sides in the contemporary debate about relativism. On the one hand, relativists believe that the contingency of knowledge production makes universal knowledge impossible. On the other hand, critics of relativism often view universalism as an ahistorical essence, as something rooted in nature, without a historical or social context. We can see this, for instance, in the current discussion about human nature.
What both sides underestimate is the role of the active human subject in transcending their immediate situation, and hence the possibility of historically situated knowledge that also bears the potential of more universal validity.