The Freedom of the Will Desiderius Erasmus

De libero arbitrio diatribe sive collatio was nominally written to refute a specific teaching of Martin Luther, on the question of free will.[note 1] Luther had become increasingly aggressive in his attacks on the Roman Catholic Church to well beyond irenical Erasmus' reformist agenda.[2][note 2]

One of the propositions ascribed to Luther and anathemized by Pope Leo X's bull Exsurge domine (1520) was that "Free will after sin is a matter of title only; and as long as one does what is in him, one sins mortally."[4]

Luther responded, publishing his Latin Assertio omnium articulorum which included the statement "God effects the evil deeds of the impious"[5] as part of the Wycliffian claim that "everything happens by pure necessity,"[note 3] so denying free will. (For the popular German version of this work, Luther sanitized his text for Article 36 to remove the arguments that "God is the cause not only of good deeds in man but also of sins, and that there is no natural power of the human will to direct man's actions either for good or for bad."[6]: 485 )

Bishop John Fisher published a detailed response to the Latin version's arguments as Confutation of the Lutheran Assertion in 1523.

Erasmus decided necessity/free will was a subject of core disagreement deserving a public airing, and strategized for several years with friends and correspondents[7] on how to respond with proper moderation[8] without making the situation worse for all, especially for the humanist reform agenda..

Erasmus' eventual irenical strategy had three prongs:[note 4]

• first, a dialogue Inquisitio de fide to turn down the general heat and danger, and to set the stage for calm debate, which asked the question of whether Lutherans were heretics and, because they accepted the Creed, proposed that Lutherans must not be classed as heretics;[9]
• second, six months later, a small book On Free Will addressed as much to issues of limits of authority, discourse, biblical interpretation, as to free choice of humans in the things of God;
• third, published the same day as On Free Will, a small book De immensa misericordia dei (On the Immense Mercy of God),[10] written ostensibly as a model sermon which provided Erasmus' positive alternative to Luther's idea in a non-controversial genre,[note 5] without mentioning him.[11][note 6] It set up that God was not arbitrary, against the claims of predestination; notably it sets "mercy" as a synonym for all kinds of grace, allowing a far broader range of scriptures to be applied than those that used the term "grace":[note 7] "What is the grace of God, if not the mercy of God?"[note 8] (It also warns the audience against Manicheeism, which proposed two Gods, the just but not equally good God of the Old Testament, and the good but not equally just God of the New.)[10]: 117 

Terminology

• Synergism is the idea that adult salvation or justification involves some sort of co-operation (noting that the co- does not connote equality of the parties, God's grace always being in some way prior.) This is the view that Erasmus prefers in On Free Will.
• Monergism is the idea that God brings about an individual's salvation or justification regardless of their co-operation. This is the view associated with the early leaders of the Reformation such as Luther.
• Semi-Pelagianism is the idea that the beginning of faith is a free choice, with grace supervening only later.
• Pelagianism is the idea that humans have free will to achieve perfection