奧古斯丁把意願劃分為始祖亞當墮落前和墮落後兩個階段。在與摩尼教徒福圖納圖斯的辯論中，他論證說，道德責任基於意願的自由決斷的自主性，不基於其方向的多樣性；即使人類的意願在亞當墮落後陷入了犯罪的必然性，但亞當及其後裔仍然可以出於決斷的自主性而犯罪，就不得不繼續承負自己的道德責任。「非意願的罪」是一個自相矛盾的概念，不能解釋奧古斯丁早期意願哲學中的理論變革。

Augustine divides voluntas into two stages, before the fall and after the fall of Adam. In the debate with Fortunatus the Manichee, Augustine argues that moral responsibility is based on the autonomy, but not on the alternatives of our free choice. That is, although human voluntas, after the fall of Adam, is plunged into the necessity of sin, Adam and all the descendents still sin by the autonomy of their own free choice, and therefore have to undertake the moral responsibility for the sin. The paper will show that “involuntary sin” is a self-contradictory concept, which doesn’t elucidate the theoretical reformations in Augustine’s early philosophy of voluntas.