The heavenly eye is one of the most powerful supernatural powers in taoism. It can make people lose their will to resist. When the heavenly eye disappears, it is replaced by the devils eye, which is the same as the tap. This means that if you have just one eye, you can lose your will. This is why chengzi would have died if he had tried to kill his brother. He wonders how he could have let his brother die so easily.
The heavenly eye is one of the most powerful supernatural powers in taoism. It can make people lose their will to resist. When the heavenly eye disappears, it is replaced by the devils eye, which is the same as the tap. This means that if you have just one eye, you can lose your will. This is why chengzi would have died if he had tried to kill his brother. He wonders how he could have let his brother die so easily.