The other side of good and evil. When you stare into the abyss, the abyss stares at you. The complete expression of this sentence is "those who hit monsters should be careful not to become monsters." When you stare at the abyss from a distance, the abyss is also staring at you. "This sentence comes from the famous German philosopher Friedrich Wilhelm Nietzsche's The Other Side of Good and Evil. "The other side of good and evil is the prelude of Nietzsche's future philosophy. Radical criticism of western metaphysical tradition has become a key concept to help people get rid of all kinds of prejudices in their minds and stand on the other side of good and evil for sincere thinking.