6 - Species and the metaphysics of evolution

Summary

INTRODUCTION: SPECIES CONCEPTS AND METAPHYSICS

In the previous chapter, I sketched out a potential solution to the species problem based on an idea implicit in the hierarchical pluralism of Mayden and de Queiroz, the division of conceptual labor. This solution distinguishes theoretical concepts that tell us what species things are, from operational concepts, or more accurately correspondence rules, that tell us how to identify and individuate species taxa. I also tentatively endorsed the basic idea behind the theoretical concepts proposed by Mayden and de Queiroz that treats species as segments of population lineages. This idea reflects the basic evolutionary assumption that species taxa have two dimensions, synchronic and diachronic. They exist at a particular time as population of organisms, and over time as a lineage of ancestors and descendants. But even if we were to accept as unproblematic this more general claim, along with the specific conception of species as segments of population lineages, there would still be questions about the nature of species taxa. There is still more to the species debate.

There is also a metaphysical, or more specifically, an ontological question: Given that species taxa have the features we think they have, what fundamental kinds of things are they? This question is asking us to think about species at a more general, and more fundamental level. In this chapter, we will be looking at this question, how it has been answered and why, and what the implications are for each metaphysical (or ontological) stance.