Planet of the Walking Dead

The brain went through three stages in the course of evolution. The first was instinct, what people commonly call the “reptilian brain”: only the most basic instincts, such as eating, drinking, relieving oneself, sleeping, and mating. The second was emotion, a more advanced stage known as the “monkey brain,” which includes feelings such as happiness, anger, sorrow, and joy. The third was intelligence, logical reasoning, and judgment: the cerebral cortex possessed by humans.

In a sense, human civilization is built upon the cerebral cortex.

Yet from the perspective of a much more distant future, humanity will eventually develop a fourth, far more advanced brain: the mysterious brain.

Humans who evolve the mysterious brain will become the new humanity, while those who do not evolve will become useless people, and useless people are destined to become walking corpses!