奧古斯丁在米蘭皈依的究竟是基督教信仰還是新柏拉圖主義哲學？這是學界長期以來爭論不休的問題。本文從「聖言與人言的對話」這一角度出發，力圖更加準確而深入地把握加西齊亞根對話錄的文體形式和思想傾向，並論證奧奥古斯丁的早期作品與標誌其宗教思想和寫作方式之成熟的《懺悔錄》之間的連貫性。基於這一連貫性，我們認為，雖然加西齊亞根的奥奧古斯丁仍處在從新柏拉圖主義哲學向基督教思想過渡的時期，但是他在米蘭皈依的是基督教，而非新柏拉圖主義。

The nature of Augustine’s conversion, whether it was to Christianity or Neoplatonism, has been a matter of debate for a long time. Following the thread of the dialogue between divine word and human word, this article offers a new interpretation of the literal form and intellectual tendency of the Cassiciacum dialogues, with a view to demonstrating the continuity between the early works of Augustine and the Confessions, the masterpiece that marks the maturity of his religious thinking as well as his manner of writing. Based on this continuity, this article concludes that in Milan Augustine was converted to Christianity, not Neoplatonism.