"Although the most acute judges of the witches and even the witches themselves, were convinced of the guilt of witchery, the guilt nevertheless was non-existent. It is thus with all guilt"

This quote by Friedrich Nietzsche is a commentary on the principle of guilt. He is recommending that even when individuals are persuaded of someone's guilt, it might not really exist. He is indicating that regret is a subjective concept, which it is not constantly based upon realities or truth. He is likewise recommending that guilt is an effective feeling that can be used to manipulate people and control their habits. He is stating that regret is often used as a tool to control people, which it is not always based upon reality or justice. He is alerting us to be familiar with the power of regret and to be mindful not to be controlled by it. He is also recommending that we ought to be careful to not judge others too harshly, as guilt is typically based upon subjective viewpoints and not facts.