INTRODUCTION to CHAPTER FIVE
This chapter discusses the concept of selection. It is trickier than it may appear at first sight. It is striking that numerous authors in the social sciences use terms such as “variation-selection-retention model” without defining selection or apparently realizing its complexity.
Selection implies an ontology of multiple entities existing at the same point in time. Critics of the selection concept often overlook this. They often regard “evolution” as the process of development of a single entity, which of course is one of several possible meanings of that word. Generalized Darwinism applies to a population of multiple entities.
Selection neither implies progress nor excludes cooperation. It can take different forms and involves multiple possible mechanisms.
Our definition of selection (in section 5.1) follows closely the work of George Price. The definition involves an anterior and posterior set of entities in a population. The posterior set can be a subset of the anterior set (which we call subset selection), or it can be some kind of offspring of the anterior set (which we call successor selection). This definition is helpful for analytical purposes. It can be made operational, and thus useful in empirical research by translation to a regression framework.
Much discussion of selection in the social sciences concentrates simply on subset selection, which in contrast to successor selection, is unable to generate novelty.
The definition of selection involves the tricky concept of fitness: by definition with selection the composition of the posterior set is causally related to fitness. Fitness is easy to define in abstract, mathematical terms. But it is difficult to define its specific expression, in both the biological and the social world. In any case, it does not simply mean survival, thus avoiding a tautological formulation of selection. We see the fitness of an interactor as the propensity of its replicators to replicate, by diffusion to other interactors or by making copies of the interactor.
The objects of selection are interactors. We write of “selection of” such objects. The outcome of the change in the population of interactors is a change in the pool of replicators in the population. This is “selection for”. (The philosopher Elliott Sober introduced the terms “selection of” and “selection for” but we use the distinction in a different way.)
In their 1982 book, Richard Nelson and Sidney Winter describe the introduction or curtailment of routines by management within an organization as selection. In contrast, in our conceptual framework only interactors can be objects of selection. We call the type of process described by Nelson and Winter “replicator manipulation”.
We also define the concept of diffusion in this chapter. Diffusion is a type of inheritance that involves the copying of replicators, but not of interactors. Diffusion is common in the social domain, particularly in regard to ideas and technologies. In these cases, associated habits and routines are copied from one interactor to another.
1. Why does selection not always relate to progress or efficiency, even if it is related to fitness?
2. In what way can a selection process create novelty?
3. Are the difficulties with the fitness concept an insurmountable barrier?
4. What is the relationship between selection and replication?
5. Is diffusion related to fitness?