The human brain differentiates humans from other animals. According to Mary’s deceased husband Roy, the ability to perceive the functioning (or non-functioning) of the brain is the defining quality of humanity. The human brain therefore symbolizes humans’ ascendent evolution. Humans created nation states, they created the global financial system, and they created the terrible wars which seem to inevitably result from their other creations. In addition, humans create technology such as the cruise ship and Mandarax. Humans create the Nature Cruise of the Century as well as the celebrity gossip and luxury treatment that this entails, all while people are starving to death. The big-brained humans want to travel in luxury to the place where Charles Darwin first refined his theory of evolution, creating a symbolic loop for humanity’s ascendancy, powered by the big brains which distinguish them from other animals.

For Leon, humanity’s big brain is a curse. He repeatedly criticizes the big brain as a relic of long ago that the species must abandon to be happy. Leon blames the brain for all that is wrong with people, and he attributes humanity’s happy future to the loss of the big brain. Whenever Leon describes anything bad that humans have done, whether war or inequality or anything else, he refers to the big brains as a point of contrast with the future, when humanity’s brains are much smaller, and humans therefore have less to worry about and less ability to inflict pain on one another and the world around them.