In his autobiographical account, the Munqidh min al-Dalāl, al-Ghazālī reflects on his conversion from skepticism to faith. Previous scholarship has interpreted this text as an anticipation of Cartesian positions regarding epistemic certainty. Although the existing similarities between al-Ghazālī and Descartes are striking, the focus of the present essay lies on the different philosophical aims pursued by the two thinkers. It is thus argued that al-Ghazālī operates with a broader notion of the Self than Descartes, because it is inclusive of the body. And it is shown that the two philosophers use completely diverging paradigms. While Descartes models his notion of evidence after mathematical certainty, al-Ghazālī draws his famous 'ilm al-yaqīnī (certain knowledge) from a religious context.