ʿIlm al-yaqīn, ʿayn al-yaqīn, ḥaqq al-yaqīn

A person who possesses yaqīn (certainty) is, in the language of the scholars, and in the absolute sense, not subject to doubt. Since it does not occur in the revealed texts (naṣṣ), the term yaqīn is not used as an attribute of Allah. Both ʿilm al-yaqīn (certainty attained through knowledge), ʿayn al-yaqīn (certainty attained through direct vision), and ḥaqq al-yaqīn (certainty attained through true reality) are, in essence, yaqīn itself. According to the terminology of the Sufis, ʿilm al-yaqīn is knowledge acquired through rational proof and evidence. ʿAyn al-yaqīn is knowledge that is in the ruling of bayān (clear exposition), that is, knowledge whose judgment is manifest. Ḥaqq al-yaqīn, on the other hand, is knowledge that is manifestly clear, being both ʿilm al-yaqīn and ʿayn al-yaqīn, and is in the quality of bayān (clear exposition). ʿIlm al-yaqīn is for those who possess intellect and inference.