The following papers evolved as a continuing discussion begun by John Harris in his paper “Stem Cells, Sex, and Procreation” (CQ Vol 12, No 4). First, Julian Savulescu responds to the Harris paper, with Harris following with a response to Savulescu. Next, the two authors suggested a joint paper in which, despite their continuing differences, they would examine where they agree. This remarkable collection of papers, presented here, is a rare opportunity to follow the developing thoughts of two of today's most influential philosophers through what they describe as “a somewhat tortuous process of reason and argument.” They test their own positions as they challenge the views of the other, and they discover points at which their intellectual paths converge.

This Harris-Savulescu debate illustrates the value of sharing publicly the sorts of philosophical wrestling and metamorphosis that usually remain private. As they observe in the conclusion of “The Creation Lottery”:

There could be no better example for the rest of us than to watch this process in action. For this reason and in tribute to Harris and Savulescu, CQ is inaugurating “The Great Debates” series, in which noted bioethicists will debate in these pages some of the most perplexing contemporary bioethics issues.