The neocortex can temporarily control breathing, as when you consciously decide to hold your breath. But if the brain stem detects that your body needs more oxygen, it will ignore the neocortex and take back control. Similarly, the neocortex might think, “Don’t eat this piece of cake. It isn’t healthy.” But if older and more primitive parts of the brain say, “Looks good, smells good, eat it,” the cake can be hard to resist. This battle between the old and new brain is an underlying theme of this book. It will play an important role when we discuss the existential risks facing humanity.
