De libero arbitrio (sometimes translated "Dialogue on Free Will") is one in a series of dialogues written by Lorenzo Valla. The work discusses his views on the concept of free will as it pertains the Catholic Church's opinion on predestination at the time. The concept of predestination, in the opinion of the Catholic Church, deals with the fact that God knows how we will act and has predetermined our eternal destination. Many philosophers of the time argued that if humans' lives are in fact predetermined by God, than in reality the concept of free will is simply an illusion. Essentially the argument is that if God has created us already knowing the decisions we will make, than those decisions are not actually ours. Valla, through a fictional dialogue amongst the work's characters, defends the idea that the concepts of predetermination and free will can coexist. In the work, Valla states that he is attempting to directly refute the works of the 6th century philosopher Boethius. Source: Wikipedia (en)