Umwelt

In 1909, the biologist Jakob von Uexküll introduced the concept of the umwelt. He wanted a word to express a simple (but often overlooked) observation: Different animals in the same ecosystem pick up on different environmental signals. In the blind and deaf world of the tick, the important signals are temperature and the odor of butyric acid. For the black ghost knifefish, it’s electrical fields. For the echolocating bat, it’s air-compression waves. The small subset of the world that an animal is able to detect is its umwelt. The bigger reality, whatever that might mean, is called the umgebung.

The interesting part is that each organism presumably assumes its umwelt to be the entire objective reality “out there.” Why would any of us stop to think that there is more beyond what we can sense? In the movie The Truman Show, the eponymous Truman lives in a world completely constructed around him by an intrepid television producer. At one point, an interviewer asks the producer, “Why do you think Truman has never come close to discovering the true nature of his world?” The producer replies, “We accept the reality of the world with which we’re presented.” We accept our umwelt and stop there.

David Eagleman on how each species of animal senses only a small portion of the world, and assumes that small fraction is the entire world.