What Makes Us Human?

Maria Popova reviews Joanna Bourke's What It Means to Be Human: Historical Reflections from the 1800s to the Present:

[I]n The Third Chimpanzee, [Jared Diamond] wondered how the 2.9 percent genetic difference between two kids of birds or the 2.2 percent difference between two gibbons made for a different species, but the 1.6 percent difference between humans and chimpanzees makes a different genus. …

Curiously, Bourke uses the Möbius strip as the perfect metaphor for deconstructing the human vs. animal dilemma. Just as the one-sided surface of the strip has "no inside or outside; no beginning or end; no single point of entry or exit; no hierarchical ladder to clamber up or slide down," so "the boundaries of the human and the animal turn out to be as entwined and indistinguishable as the inner and outer sides of a Möbius strip."

(Video: Möbius strip II, by M.C. Escher)