A philosophical introduction

In the last chapter we saw that reductionism, for all its successes, has disadvantages. Its benefit is that, by focusing always on the minute components of biological processes, reductionism produces those causal explanations so valuable to research biologists in general, and to medical researchers in particular. The cost comes when the larger picture is undervalued, or even ignored; when the whole, living, organism is forgotten in the drive to catalogue its parts. I said, therefore, that hard though it may be to escape the clean confines of reductionist biology, the corrective comes by taking a wider perspective – by lifting your eyes from the test tube, and looking around. You do not need to look far, for in the life sciences, the largest picture of all is provided by evolutionary theory. So, having spent the last chapter appreciating reductionism, but also cautioning against the narrowness it can foster, I will now look at the characteristics of evolutionary theory that put it at the heart of biology.

Evolutionary theory is a loose collection of ideas surrounding the idea of change in living things. It is preferred territory for an amazing – and amazingly disunited – company. Indeed, it is not hard to find evolutionary ideas pressed into supporting contrary arguments: that people are naturally aggressive (or peaceful); that the pace of evolution is even (or irregular). I shall cover some of the disputes of evolutionary theory and in the process, I hope, portray its enduring achievements.