De libero arbitrio

De libero arbitrio voluntatis (On Free Choice of the Will), often shortened to De libero arbitrio, is a book by Augustine of Hippo which seeks to resolve the problem of evil in Christianity by asserting that free will is the cause of all suffering. The first of its three volumes was completed in 388; the second and third were written between 391 and 395. The work is structured as a dialogue between Augustine and his companion Evodius; it ranges over several topics, and includes an attempted proof of the existence of God. Intended also as a refutation of Manichaeism, De libero arbitrio denied God's responsibility for sin and emphasised human freedom and accountability. As a result, it became associated with Pelagianism, another doctrine which Augustine considered heretical; he subsequently defended the work by softening its libertarian message. In the 13th century, Thomas Aquinas expanded on the political ideas expressed in this book, and is credited with popularising Augustine's claim that an unjust law is not a law. Development Prior to his conversion to Christianity, Augustine had been an adherent of Manichaeism, which taught that the principle of good, God, was eternally opposed by a powerful principle of evil. This dualistic cosmology sought to explain the presence of evil in the world as a result of the conflict between these two deities. Augustine, however, was left unsatisfied by this explanation, and eventually drifted away from Manichaeism to be baptised into the Catholic Church in 387 AD. De libero arbitrio, begun later the same year, was an attempt at a new solution to the problem of evil, one which would preserve Christian monotheism while upholding the goodness and omnipotence of God. This was one of several anti-Manichaean works authored by Augustine around this time, partially in a deliberate attempt to distance himself from his former beliefs. The book's first volume was completed in 388, while Augustine was living in Rome; the second and third volumes were written between 391 and 395, after he had been ordained a priest in Africa. The work was loosely based on real conversations which Augustine had with his friend and correspondent Evodius, who is made the second character in the dialogue. However, the dialogue format is only inconsistently followed, and Evodius disappears from sight for much of the third volume, while Augustine indulges in a series of extended monologues which anticipate the methods of his later works.