Absence of good

Absence of good (Latin: privatio boni), also known as the privation theory of evil, is a theological and philosophical doctrine. It states that evil is not a substance as good is but merely an absence or lack of good. Therefore, everything that exists is good simply because it exists. It could be suggested that evil is either non-substance or complete absence. Evil can be considered to be a parasite on the good it lacks and corrupts.

The privation theory is associated mostly with late antique and medieval Christianity, with particular attention to Augustine of Hippo. Drawing on Neoplatonism, especially Plotinus's views, he stated that evil is a privation of goodness that God created in all things. The theory was later discussed by Boethius, Pseudo-Dionysius, John of Damascus, Thomas Aquinas, and early modern philosophers including Spinoza and Leibniz, in modified forms

Similar concepts appear outside historic Christian thought. For example, authoritative texts of the Baháʼí Faith describe evil as "nonexistence" or "nothingness". In contemporary philosophy of religion, versions of the privation theory have been discussed within neo-Thomist metaphysics.

Because the theory holds that evil is not a positive reality created by God, it is discussed in relation to the problem of evil. According to the theory, if the evil is the absence of good rather that something created by God, then God creates good and permits the absences that constitute evil. Some critics state that the theory has difficulty accounting for evils that appear to have a positive character.