 This makes all the more interesting Clarke’s own disagreement with those who have defended the idea that biofilms are evolutionary individuals (Clarke 2016a), wherein she argues that many of the important claims that underpin ascriptions of multicellularity to biofilms—such as that they are physiologically unified systems or contain cells that interact synergistically—are either not verifiable (e.g., they have higher-level adaptions) or are false (e.g., they display heritable variation in fitness). While Clarke’s functionalism means that she remains open to the suggestion that there may be some non-genetic form of heritability in biofilms (Doolittle 2013), she takes the relevant empirical evidence here to be indecisive (Clarke 2016a: 202).