Umwelt

Von Uexküll's "universe of the meaningful": the slice of the world an organism can sense and act upon, which for Agüera y Arcas includes its own hidden internal states (hunger, dopamine) and, for social animals, other minds above all. Because perception exists only where action is possible, an umwelt is sensory-motor at once. Language is described both as a compression scheme for the human umwelt and as an umwelt in its own right — a general-purpose motor affordance — which is why a model trained on text inherits our senses ("large language models do have noses: ours"). Brain regions have umwelten too, consisting largely of each other.