The second prominent Muslim philosopher was Abu Nasr Farabi (870-950).

The second prominent Muslim philosopher was Abu Nasr Farabi (870-950). He is considered as the founder (muassis) of Islamic philosophy especially political philosophy. An influential group of scholars called themselves Ikhwan as-Safa (Brothers of Purity). They established their secret group in 983 in Basra. Their treatises include 51 parts which covers various sciences. Ibn Sina One of the greatest Muslim philosophers is Ibn Sina/Avicenna (980-1037).

His book as-Sifa is an encyclopedia of all sciences of his time.. It contains logic, metaphysics, mathematics and physics. Mathematics includes arithmetic, geometry, astronomy and music. Physics includes different branches of natural sciences, biology and psychology. This book was translated into Latin and was known as Sufficientiae. Ibn Sina’s thought was well known and respected both in Islamic world and in medieval Europe.

Copleston says: “When portions of writings of Avicenna were translated into Latin in the twelfth century, the Christian world found itself faced for the first time with a closely knit system which was bound to exercise a strong attraction on certain minds.” For example, Gondysalvi both in psychology and cosmogony refers to Ibn Sina and tries to harmonize the latters’ ideas with Christianity.

Ibn Sina was not only a commentator of Aristotle, but, in addition to this, he had his own independent philosophical system in which he refers both to Greek philosophy and Islamic belief system.

As Copleston says, “…however much he borrowed from former philosophers, Avicenna had thought out his system carefully and independently and had welded it into a system of a peculiar stamp.” Islamic view of human knowledge and illumination, distinction between essence and existence, and argument for necessary being from contingent being were among the ideas that via Ibn Sina came into medieval philosophy.

One of the contributions of Muslim philosophers was to show how and to what extent one can combine between Greek philosophy and religious beliefs. The connection of physics and metaphysics which was developed in the thought of Thomas Aquinas was largely inspired by Islamic philosophy particularly that of Ibn Sina. Another hotly debated idea in medieval philosophy that has its origin in Ibn Sina, is the idea of intentions. Ibn Sina distinguished between first and second intentions.

First intentions are universal concepts that are applicable on objective realities, such as the concept of human and horse.