 The third issue is religion. How does “the Absolute” relate to “God”? This was not simply a question internal to Idealist philosophy, but of far wider cultural and intellectual concern, partly because of the threat that Darwinian biology and Biblical “higher” criticism seemed to pose for Christian theism, and partly because of the rise of anthropological inquiry and the new “science of religions”. Edward Caird's brother John, a prominent churchman, Professor of Divinity at Glasgow, subsequently Principal of the University, and also an Idealist in philosophy, devoted this Croall Lectures to this topic. A more sustained opportunity to address these questions arose with the establishment in 1882 of the Gifford Lectures at the four Scottish Universities. Several series of these important lectures were given by the principal Scottish Idealists, and subsequently published—The Evolution of Religion (1891–2) by Edward Caird (widely regarded as his philosophical masterpiece), Naturalism and Agnosticism (1896–8) by J.S. Ward, and The Fundamental Ideas of Christianity (1912–13) by John Caird, are three of the most important. All of them deploy the resources of Idealist philosophy to defend a version of theism that is compatible with evolutionary biology. They do so in part by interpreting the concept of “evolution” philosophically so that both thought and religion are understood to evolve, no less than biological organism.