Dr. Noll, McManis Professor of Christian Thought at Wheaton College, explains:
By an evangelical ‘life of the mind’ I mean more the effort to think like a Christian—to think within a specifically Christian framework—across the whole spectrum of modern learning, including economics, political science, literary criticism and imaginative writing, historical inquiry and philosophical studies, linguistics and the history of science, social theory and the arts. [T]he point is not simply whether evangelicals can learn how to succeed in the modern academy. The much more important matter is what it means to think like a Christian about the nature and workings of the physical world, the character of human social structures like government and the economy, the meaning of the past, the nature of artistic creation, and the circumstances attending our perception of the world outside ourselves. Failure to exercise the mind for Christ in these areas has become acute in the twentieth century. That failure is the scandal of the evangelical mind.Mark A. Noll, The Scandal of the Evangelical Mind 7 (Eerdmans, 1994).
In March of 1995, First Things printed a Symposium on this topic in response to (or rather, as a result of) Noll's book. The comments from First Things make for enlightening reading.
For a more recent reflection on Noll's important book, take a look at this offering from the Trinity Forum.