Can communities cause?

Lynch et al. (Biol Philos, 2019) propose an extremely useful framework to assess microbiome research. By utilising advances in the causation literature, they argue that many of the claims in microbiome research are ‘weak or misleading’ as these claims lack stability, specificity, or proportionality. In the final paragraph before the conclusion they entertain and rapidly dismiss the ‘ecological version’ of microbiomes, in which microbiome properties are emergent from their constituent populations and can fulfil Koch’s postulates. I assess the possibility of microbiomes having emergent causal efficacy on host health and suggest they can.