It has become increasingly clear that there is a vast array of microorganisms on and in the human body, known collectively as the human microbiome. Our microbiomes are extraordinarily complex, and this complexity has been linked to human health and well-being. Given the complexity and importance of our microbiomes, we struggle with how to think about them. There is a long list of competing metaphors that we use to refer to our microbiomes, including as an “organ” containing our “second genome,” (...) as a “symbiont” in the human “holobiont,” and as an ecological “community” in the human “ecosystem,” among others. Each of these makes different assumptions about the fundamental biology of the human-microbe system, with important implications for how we choose to study microbiomes, and the therapies we envision for correcting microbiome-linked disorders. We believe that it is time to move beyond metaphors, and we propose a scientifically pluralist approach that focuses on characterizing fundamental biological properties of microbiomes such as heritability, transmission mode, rates of dispersal rates, and strength of local selection. Such an approach will allow us to break out of the confines of narrow conceptual frameworks, and to guide the exploration of our complexity as chimeric beings. (shrink)

A quarter of a century ago, a group of scientists and conservationists introduced ‘biodiversity’ as a media buzzword with the explicit intent of galvanizing public and political support for environ...

In 1966, Laura Bohannan wrote her classic essay challenging the supposition that great literary works speak to universal human concerns and conditions and, by extension, that human nature is the same everywhere. Her evidence: the Tiv of West Africa interpret Hamlet differently from Westerners. While Bohannan’s essay implies that cognitive universality and cultural variation are mutually exclusive phenomena, adaptationist theory suggests otherwise. Adaptive problems ("the human condition") and cognitive adaptations ("human nature") are constant across cultures. What differs between (...) cultures is habitat: owing to environmental variation, the means and information relevant to solving adaptive problems differ from place to place. Thus, we find differences between cultures not because human minds differ in design but largely because human habitats differ in resources and history. On this view, we would expect world literature to express both human universals and cultural particularities. Specifically, we should expect to find literary universality at the macro level (e.g., adaptive problems, cognitive adaptations) and literary variation at the micro level (e.g., local solutions to adaptive problems). (shrink)

“Dysbiosis” is a common but vague term featured in the microbiome literature, often invoked to indicate some kind of imbalance among microbiota. There is no agreement on how to define or even characterize dysbiotic microbiomes. Building on the work of Morar and Bohannan, who explore five interpretations of “microbiome,” I offer a short supplemental analysis of what plausibly counts as “dysbiosis” according to each of the five distinct conceptions. My aim is to provide a more nuanced basis for interpreting (...) claims, primarily and most generally; and more specifically, provide a basis for those advancing pluralist or eliminativist arguments. (shrink)