Shahab Al-Din Yahya Suhrawardi, known as Shaykh-e Ishraq, is a famous Iranian philosopher who lived in the 12th century. His thoughts form a consistent and coherent philosophical system that a detailed study of his writings in Persian reveals a theory of knowledge generally called “Knowledge by Presence”. Suhrawardi, who claims to have discovered the truth first and then embarked on a path to find the rational basis of his experiential wisdom, represents a thinker who tried to reconcile rational discourse and inner purification and to achieve this goal, he presents his theory through the intellectual and mystical school of Enlightenment for lovers of truth.