Your macrobiome weighs around two kilos and contains 100 trillion tiny lives. The microbiota that came out in your faeces yesterday outnumber the humans on the planet. These trillions of companions, travelers, populate the greenhouse ecosystem under your skin. Your brain knows them even if you don’t.

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The gut brain isn’t inarticulate; but the head brain has a different syntax. The head brain works to make tiny technology to send down into the depths and report back: ingestible sensors made of silicon-based circuitry and biodegradable minerals, with batteries consisting of nutrients and running on stomach juices.

These foreign messengers sent into the inner tubes can inform the head brain about bacterial infections, gastrointestinal disorders, medication uptake, riots, protests, petty disagreements, breakups, ecological shifts, mycological takeovers, and of course the weather down there. What the sensor can’t tell you is whether your conscious state is messing with your gut, or whether it’s the other way around.

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The body works hard to control the membrane – the interface, however slight, between inside and out. But the body is not concerned with authorship. The body is always authored by other bodies, the micro-bodies, the microbiota. Being a good host to others has always been the key to self-care.

Bare Life: Gut is a podcast by Jenna Sutela and Elvia Wilk. It features a meal and a conversation about embodiment, asking: What does it mean to be in your body here and now, without relying on either an idealized prehuman past or an inhuman future? What really are the basic substrates of a healthy human existence? The topics discussed vary from bacteria dealers to microscopic healers and from fermentation to self-experimentation. Digestion is a question.

Including excerpts and ideas from work by Benjamin Bratton, Giulia Enders, Alexis Goertz, Michael Pollan, and Gregory Whitehead.