Abstract(s)
Extensive social choice theory is used to study the problem of measuring group fitness in a two-level biological hierarchy. Both fixed and variable group size are considered. Axioms are identified that imply that the group measure satisfies a form of consequentialism in which group fitness
only depends on the viabilities and fecundities of the individuals at the lower
level in the hierarchy. This kind of consequentialism can take account of the
group fitness advantages of germ-soma specialization, which is not possible
with an alternative social choice framework proposed by Okasha, but which is an essential feature of the index of group fitness for a multicellular organism
introduced by Michod, Viossat, Solari, Hurand, and Nedelcu to analyze the
unicellular-multicellular evolutionary transition. The new framework is also
used to analyze the fitness decoupling between levels that takes place during
an evolutionary transition.