ABSTRACT
In this chapter, I revisit the well-known Ghiselin/Hull thesis that species are individuals. I argue that some species are indeed individuals, but individual processes rather than individual things. However, while species processes are the norm among vertebrate animals and common among many groups of eukaryotes, in other parts of the taxonomic tree, they may be quite rare. If we started at the beginning, in terms of both time and prevalence, with microbes, we would not be tempted to think that species in general were individuals. That some but not all species are individuals confirms the importance of distinguishing sharply between species as the lowest level of a classificatory scheme, intended to apply to all organisms, and species as a theoretical term, with a reference the extent of which is a strictly empirical matter.
