“This was a very innocent planet, except for those great big brains.”

Leon, the narrator, has a wealth of perspective after watching the evolution of the human race for a million years. To him, the ancient humans’ big brain is the cause of many of their problems. He directly contrasts the existence of big brains with the innocence of the species, suggesting that they’re mutually exclusive. Once humans evolved to have a big brain, he suggests, they lost their capacity for innocence.

“It was expected by them that, because of his inbred parentage, he would become a moral monster.”

Wait’s heritage explores the theme of Nature Versus Nurture. Wait is the product of an inbred parentage, something that Wait’s world culturally abhors. He’s treated like the product of inbreeding and told that on a genetic level this makes him more prone to criminality and immorality. Wait may have had the capacity to be a good person, but his entire life has become a self-fulfilling prophecy, in which he has become a criminal because everyone has treated him like a criminal from his earliest years.

“This financial crisis, which could never happen today, was simply the latest in a series of murderous twentieth century catastrophes which had originated entirely in human brains.”

The financial crisis that brings about the collapse of global society is the product of humans’ big brain. To Leon, these big brains are a curse. Humans have the capacity to think up something as intricately complex as the global financial system but, in doing so, are inventing the tools of their own demise.