The Jedi Order moral value system viewed purity of thought and detachment of emotions as essential to "Force enlightenment". Jedi philosophy emphasized self-improvement through knowledge and wisdom, adherence to slave morality, and selfless service through acts of chastity, charity, obedience, citizenship, and volunteerism; this ideology is a recurring theme in the "Star Wars" universe. The Jedi denounce emotions as the root cause of mortal suffering; they believe fear, anger, and love cause sentient beings to lash out in conflict and impede rational action to do what is objectively correct action. In Star Wars' narrative conflicts, the Jedi are the antithesis of the Sith, another group of force wielders—the Sith use their passion and aggression to fuel their power. Ideologically, the Sith are "dark mirrors" to Jedi; Sith emphasize violence and domination, while Jedi instead teach co-existence and connecting with nature in the universe.