“It is all that we know, and so we easily mistake it for all there is to know. This is an illusion, and one that every animal shares.”

Yong, in describing how each species perceives the world within its own umwelt and, thus, constructs a species-specific reality, emphasizes that what is “real” for one species is simultaneously an illusion because it does not encompass all that can be known, perceived, or experienced in the world. Humans’ umwelt is the means by which they perceive and experience the world, but its opening into the world is simultaneously and necessarily limiting.

“This is a book not about superiority but about diversity.”

Yong again references Uexkull’s theory of the umwelt and the diversity of umwelten. There are as many umwelten as there are species. Each of these is unique to each species, and none is better than any other. Uexkull eschews traditional approaches that value complexity over simplicity, as if complexity in and of itself is of greater value than simplicity. Yong refuses human exceptionalism, or the idea that humans are different in a way that makes them superior to all other species. Instead, he and Yong ask humans to approach other animals in all their diversity.

“Nothing can sense everything, and nothing needs to. That is why Umwelten exist at all.”

Yong presents the umwelt as born out of limitations. These limitations do not carry a negative connotation but create the foundation for each umwelt. All creatures are necessarily limited in what they can sense; the limitations of sensory worlds, however, make it possible to perceive and act upon these perceptions.