Abstract
In this paper, I discuss the key role played by Carl G. Hempel's work on theoretical realism and scientific explanation in effecting a crucial philosophical transition between the beginning and the end of the twentieth century. At the beginning of the century, the dominant view was that science is incapable of furnishing explanations of natural phenomena; at the end, explanation is widely viewed as an important, if not the primary, goal of science. In addition to its intellectual benefits, this transition has important practical consequences with respect to dealing with the global problems humans everywhere will face in the twenty-first century