This is taken from a Christianity Today article on Francis Schaeffer and L’Abri, by Molly Worthen:
The modernist philosophy that he targeted in most of his writings, the bogeyman of existentialism, is passé. “Now the question is, Is there truth at all?” said worker Thomas Rauchenstein, a soft-spoken Canadian with sandy brown hair and a close-cropped beard. “Postmodernism’s critique of truth is more of a factor in students’ thinking.”
This just shows the complete misunderstanding of Schaeffer’s teachings. He saw, felt and understood post-modernism which is the reason he pushed strongly presuppositional apologetics. Presuppositonal apologetics do not rest on modernism, but on truth – which does exist no matter what worldview you hold. Schaeffer, by pushing people to the Line of Despair, helped people realise that their presuppositions were faulty, incoherent and unliveable.