‘… it is our business not to supply reality but to invent allusions to the conceivable which cannot be presented … Let us wage war on totality.’

In October’s BJGP Margaret McCartney alerted us to postmodernism’s promotion of relativism and its threat to medicine’s evidence base.2 She is of course right. But where does this epistemological turn come from? And might there be a silver lining?

Jean-François Lyotard (1924–1998) popularised the concept of postmodernism in 1979 with his book, The Postmodern Condition: a Report on Knowledge. He states, ‘The grand narrative has lost its credibility, regardless of what mode of unification it uses.’ 1 The picture of the universe painted by science represents a ‘grand narrative’, that is, a coherent picture claiming to represent a partial overview of the world itself. Postmodernism rejects this possibility, claiming that there are no final truth-models by which we can understand the world.

The obvious problem with this rejection of all grand narratives is that this position is itself a grand narrative. It fails under its own terms. But when did reason ever stop a fashionable idea?

So where does postmodernism come from, and might it be any use?

While there are many philosophical traditions, one can divide contemporary epistemology (how we construct our models of knowledge) into two broad streams, namely ‘analytic’ (or Anglo- American) versus ‘continental’ schools of philosophy. Postmodernism is a child of continental philosophy.

It is worth describing this division, as there are many occasions where clinicians and academics hopelessly fail to communicate because they are talking across different epistemological traditions.

Historically, these two approaches to epistemology stem from two different responses to the work of Immanuel Kant (1724–1804). Kant maintained that objective truth could be known to some degree via the senses. Kant discussed the problem of …