Descartes and al-Ghazâlî were led to inquire into the nature of certainty by their experiences of a fragmented world into which they were nurtured. Though theylived five hundred years apart, their searches were similar, to the extent that some have asked whether Descartes was more indebted to al-Ghazâlî than he would have been willing to admit. But despite striking similarities there are significant differences. Descartes found certainty in any experience or concept that overwhelmed him by its clarity and distinctness. Such certainty was achieved in intuition, which is a direct, experiential knowing. God guarantees thatwe shall not be deceived in this. On the other hand, al-Ghazâlî found certainty in a direct experience (dhawq) of God in whom all knowledge resides. For Descartes, God was an outside guarantor; for al-Ghazâlî, God was the very truth experienced inwardly in such a way that it could not be doubted.