Evolutionary progress from Darwin to Dawkins.

Is evolution 'progressive'? Biologists have been deeply divided in their answers to this question for over a century and a half. Darwin addressed the question in On the Origin of Species, prominent evolutionists debated the issue again in the middle decades of this century, and the issue has attracted renewed attention recently. Remarkably, the seeds of a solution to the problem may lie in Darwin's earliest private reflections on simplicity, complexity and the evolution of life.