The microbiomisation of social categories of differenceAn interdisciplinary critical science study of the human microbiome as the re-enactment of the immune self

Resumen

The human microbiome—trillions of symbiotic microbial cells harboured in the human body—challenges the tenet of a fixed and self-contained human nature by recognising the role of microbes, along with environmental and lifestyle factors, in the shaping of the immune function. Does this mean that the material-semiotic paradigm of the immune self, or immunity-as-defence (Cohen, 2009), is obsolete? Through the development of what I call ‘feminist para-ethnographies’—an intersectional method that entangles embodied experiences and ethnography with ‘fugitive’ qualitative data in technoscientific claims and quantitative research—and through using analytical frameworks from body studies, science and technology studies, and anthropology of science, this thesis asks in what ways and to what extent human microbiome research is shaping and reconfiguring biomedical practice and experimentation and older scientific and popular ideas associated with the immune self. Drawing on my research findings, I argue that human microbiome science is displacing older ideas of immunity as a guarantor of biological identity and individuality, rendering notions of the self as bounded, universal, and autonomous increasingly difficult to maintain. Yet, I hold that, simultaneously, it instantiates new forms of difference, particularly ‘immunitary privileges’ based on a higher microbial diversity, and reproduces old ones in terms of neo-colonial practices of bioprospecting biodiversity. The central argument I make in this thesis is that human microbiome science takes social groups as pre-existing, ‘natural’ phenomena, and biologises them by attributing microbes and microbial profiles to them. By correlating certain microbial species and diversity with hunter-gatherers (race), women (gender), or high-income families (class), social categories of difference become ‘microbiomised’. Importantly, this thesis also sheds light on how to (co-)produce scientific knowledge that becomes more sensitive and responsive to its social implications (Stengers, 2018) through another dimension of ‘feminist para-ethnographies’: as a material-semiotic device of registration, documentation, and analysis of embodied experiences of human–microbe relations.