Biological theory demands a clear organism concept, but at present biologists cannot agree on one. They know that counting particular units, and not counting others, allows them to generate explanatory and predictive descriptions of evolutionary processes. Yet they lack a unified theory telling them which units to count. In this paper, I offer a novel account of biological individuality, which reconciles conflicting definitions of ‘organism’ by interpreting them as describing alternative realisers of a common functional role, and then defines individual (...) organisms as essentially possessing some mechanisms that play this role. (shrink)

The problem of plant individuality is something which has vexed botanists throughout the ages, with fashion swinging back and forth from treating plants as communities of individuals (Darwin 1800 ; Braun and Stone 1853 ; Münch 1938 ) to treating them as organisms in their own right, and although the latter view has dominated mainstream thought most recently (Harper 1977 ; Cook 1985 ; Ariew and Lewontin 2004 ), a lively debate conducted mostly in Scandinavian journals proves that the issues (...) are far from being resolved (Tuomi and Vuorisalo 1989b ; Fagerström 1992 ; Pan and Price 2001 ). In this paper I settle the matter once and for all, by showing which elements of each side are correct. (shrink)

This chapter develops the idea that the germ-soma split and the suppression of individual fitness differences within the corporate entity are not always essential steps in the evolution of corporate individuals. It illustrates some consequences for multilevel selection theory. It presents evidence that genetic heterogeneity may not always be a barrier to successful functioning as a higher-level individual. This chapter shows that levels-of-selection theorists are wrong to assume that the central problem in transitions is always that of minimizing within-group competition. (...) Evidence of intralevel conflict does not qualify as evidence against the existence of a higher level of selection. (shrink)

Buchanan and Powell hope to rescue optimism about moral perfectibility from the ’received view’ of human evolution, by tweaking our view of the innate character of morality. I argue that their intervention is hampered by an unnecessary commitment to nativism, by gender bias within the received view, and by liberal presuppositions.

I argue for the usefulness of the evolutionary kind of biological individual.

The concept of adaptation is pivotal to modern evolutionary thinking, but it has long been the subject of controversy, especially in respect of the relative roles of selection versus constraints in explaining the traits of organisms. This paper tackles a different problem for the concept of adaptation: its interpretation in light of multilevel selection theory. In particular, I arbitrate a dispute that has broken out between the proponents of rival perspectives on multilevel adaptations. Many experts now say that multilevel and (...) kin selection views are mathematically equivalent to one another—that the mathematical accounting of evolution can be carried out at any hierarchical level one chooses. But what does this formal equivalence imply - are they equivalent in other ways too? I show here that significant conceptual non-equivalence has survived: the two sides commit to different views regarding how much selection has to act at a level before we can call traits at that level adaptations; about whether policing mechanisms are adaptations, and about whether non-organisms can bear adaptations. (shrink)