Right effort can be seen as a prerequisite for the other principles of the path. Without effort, which is in itself an act of will, nothing can be achieved, whereas misguided effort distracts the mind from its task, and confusion will be the consequence. Mental energy is the force behind right effort; it can occur in either wholesome or unwholesome states. The same type of energy that fuels desire, envy, aggression, and violence can on the other side fuel self-discipline, honesty, benevolence, and kindness. Right effort is detailed in four types of endeavours that rank in ascending order of perfection: 1. to prevent the arising of unarisen unwholesome states, 2. to abandon unwholesome states that have already arisen, 3. to arouse wholesome states that have not yet arisen, and 4. to maintain and perfect wholesome states already arisen.