In the same way that from the beginning Shi'ism played an effective role in the formation of Islamic philosophical thought, it was also a principal factor in the further development and propagation of philosophy and the Islamic sciences. Although after Ibn Rushd philosophy disappeared in the Sunni world, it continued to live in Shi'ism. After Ibn Rushd, there appeared such celebrated philosophers as Khawajah Nasr al-Din Mir D?mad and Sadr al-Din Shirazi, who studied, developed and expounded philosophical thought one after another. In the same manner, in the other intellectual sciences, there appeared many outstanding figures such as N?sir al-Din Tusi (who was both philosopher and mathematician) and Birjandi, who was also an outstanding mathematician.
All the sciences, particularly metaphysics or theosophy (falsafah-i Rai or hikmat made major advances thanks to the indefatigable endeavor of Shi'ite scholars. This fact can be seen if one compares the works of Nasir al-Din Tusi, Shams al-Din Turkah, Mir Damad, and Sadr al-Din Shirazi with the writings of those who came before them. 1
It is known that the element that was instrumental in the appearance of philosophical and metaphysical thought in Shi' ism and through Shi' ism in other Islamic circles was the treasury of knowledge left behind by the Imams. The persistence and continuity of this type of thought in Shi'ism is due to the existence of this same treasury of knowledge, which Shi'ism has continued to regard with a sense of reverence and respect.
In order to clarify this situation, it is enough to compare the treasury of knowledge left by the Household of the Prophet with the philosophical works written over the course of the centuries. In this comparison, one can see clearly how each day Islamic philosophy approached this scarce of knowledge ever more closely, until in the 11th/17th century Islamic philosophy and this inspired treasury of wisdom converged more or less completely. They were separated only by certain differences of interpretation of some of the principles of philosophy.
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1 Editor's note: There are all outstanding philosophers of the later period (from the 7th/13th to the 11th/17th centuries) and are nearly unknown in the West, except for Tusi who is, however, known more for his mathematical works than for his philosophical contributions.
