Introduction

Evolution is as topical as ever. Dispatches from the front lines of science report new developments (tiny homids, life earlier than ever thought, early mammal fossils with dinosaurs in the stomach contents). American school boards, courts and politicians struggle with what to teach and what not to teach. A mixture of recent technologies (gene sequencing and genomics) has led to a revitalized focus on the evolutionary dynamics of disease from bird flu to AIDS. Social Darwinism has repackaged itself as evolutionary psychology with ready pronouncements on every aspect of the human condition (from the success or lack of success of women in science to relations between men and women, the existence and persistence of homosexuality to claims about the evolution of language).

Many people would like to better participate in the debates that flow from these news reports and need primer on the issues. What are the main claims and counter claims? What areas are reporting new results and which are rationalizing pre-existing prejudices and conclusions? What should you watch out for when you hear the arguments?

These notes will provide a framework for thinking about evolution in general and selectionist accounts in particular. Over time we will dissect the most exciting recent result and the most divisive current issues. I have been meaning to work on this slim book and thought a blog might be a way to push me to develop the content.

First thoughts

Both the world itself and the path that results in this world are complex. I hope to counter over-simplification. This cuts at the creationist caricature by insisting that the world, however it came to be, is rich beyond comprehension of any one of us and to study even a part of it can be an awe inspiring experience for both the religiously enthusiastic and religiously skeptical. It also cuts at much evolutionary psychology storytelling. WE can not defend a simple line from gene to behavior or from any reasonable story of adaptations that arose in early human evolution in the savannah to explain current relationships between people. Throughout these posts I want to complicate matters. Will this leave us with a hopelessly tangled mess. In some cases we should and shall conclude that current explanations can not untangle the many factors in others we will show how it does.

We will introduce and continuously illustrate three intertwined explanations; selection, constraint and chance. These three kinds of explanation are not absent from any evolutionary account but some researchers or approaches emphasize one at the expense of the others. Deciding how to balance them and when to foreground one at the expense of the others will be a theme we return to with each example.