In a recent reply to Takacs and Bourrat’s article (Biol Philos 37:12, 2022), Autzen and Okasha (Biol Philos 37:37, 2022) question our characterization of the relationship between the geometric mean and arithmetic mean measures of fitness. We here take issue with the claim that our characterization falls prey to the mistakes they highlight. Briefly revisiting what Takacs and Bourrat (Biol Philos 37:12, 2022) accomplished reveals that the key issue of difference concerns cases of deterministic but nonconstant growth. Restricting focus to (...) such cases shows that there is in fact no reason for disagreement. (shrink)

This article proposes two conditions to assess whether an entity at a level of description is a unit of selection qua interactor. These two conditions make it possible to (1) distinguish biologically relevant entities from arbitrary ones and (2) distinguish units that can _potentially_ enter a selection process from those that have already done so. I show that the classical approaches used in the literature on units and levels of selection do not fare well with respect to either or both (...) of these desiderata. (shrink)