Good and Evil

Whether people are good or evil is an important question in a modern world full of atrocities. Where does evil come from and how can we combat it? This was also a pressing question in the centuries after the Reformation. Egoists were evil, and witches were burnt at the stake because people believed they were the servants of evil i.e. the Devil. Good, on the other hand, came from God. Can this line of thought be traced up to the present day, and how can we understand good and evil today?