At the beginning of chapter 6, Winston discusses his “worst enemy.” What is that, and why is it so particularly dangerous for him at this point?

Winston struggles with his internal turmoil surrounding this disdainful act, noting to himself that man's nervous system is his worst enemy. There is no way to fight involuntary facial spasms or talking in one's sleep. These are the actions that cannot be stopped, yet can condemn one to death.