'Ala' al-Dawla al-Simnani (d 736/1336) was a Kubraw1 sheikh lived in Simnan one hundred years after Ibn al-Arabi (d. 638/1240). He authored around ninety works in Arabic and Persian on various fields within Sufism, raised many disciples. His contribution to the stn . ( tradition mainly come to forefront regarding problems like unity, lataif (subtle organs), rijal al-ghaib (men of the unseen), waqia (dream-like mystical experiences) and tajalli (manifestation) Simnani's understanding of the unity influenced subsequent stiffs and specifically Ahmad Sirhindi (d. 1034/1624) and his sheikh Baqibillah's (d. 1012/1603) views of the unity overlap with Simnani's one. In Maktubat, Sirhindi who developed the idea of unity of the seen against the unity of the existence expresses that his understanding of being is the same with Simnani's one Simnani is also known as the first critic of Ibn al-Arabi' s conception of the unity among stiff s. Such that, whenever his name is mentioned the first thing comes to one's mind has been his criticism against Ibn al-Arabi. However, his criticism against Ibn al-Arabi was not studied as a whole looking at his ouvre. Studying Simnani's works, it is seen that his criticism is concentrated on two main problems. First is Ibn al-Arabi's employing the concept wujud al-mutlaq (absolute being) for God. He maintains that it is not convenient to use this concept for al-Haq. His second criticism is against a sentence mentioned in al-Futuhat: . In this article, causes for Simnani's critiques will be discussed and both stiffs conceptions of wujud al-mutlaq and 'ayn (quintessence) will be studied.