Final Thoughts

This brings us to the end of the journey. The discussion has ranged quite widely, so it is worth stepping back to re-capitulate the main points and to extract some general morals.Part I focused on a mode of thinking in evolutionary biology that we called ‘agential’. This involves using notions such as interests, goals, and strategies in evolutionary analysis. Agential thinking has a number of manifestations. One is the use of intentional idioms (‘wants, knows’), usually in an extended or metaphorical sense, to describe adaptive behaviour. Another is the analogical transfer of concepts from rational choice theory to evolutionary biology. There are two types of agential thinking, which need to be sharply distinguished. Type 1 treats an evolved entity, paradigmatically an individual organism, as akin to an agent with a goal towards which its phenotypic traits, including its behaviour, conduce. Type 2 treats ‘mother nature’, a personification of natural selection, as akin to a rational agent choosing between alternatives in accordance with a goal, such as maximal fitness. The former is a way of thinking about adaptation (the product), the latter about selection (the process)....