into the Muslim world, were by no means purely Greek in their outlook. Their school at Edessa
had been closed by the Emperor Zeno in 481; its learned men thereupon migrated to Persia, where
they continued their work, but not without suffering Persian influences. The Nestorians valued
Aristotle only for his logic, and it was above all his logic that the Arabic philosophers thought
important at first. Later, however, they studied also his Metaphysics and his De Anima. Arabic
philosophers, in general, are encyclopedic: they are interested in alchemy, astrology, astronomy,
and zoology, as much as in what we should call philosophy. They were looked upon with
suspicion by the populace, which was fanatical and bigoted; they owed their safety (when they
were safe) to the protection of comparatively freethinking princes.
Two Mohammedan philosophers, one of Persia, one of Spain, demand special notice; they are
Avicenna and Averroes. Of these the former is the more famous among Mohammedans, the latter
among Christians.
Avicenna (Ibn Sina) ( 980-1037) spent his life in the sort of places that one used to think only
exist in poetry. He was born in the province of Bokhara; at the age of twenty-four he went to
Khiva--"lone Khiva in the waste"--then to Khorassan--"the lone Chorasmian shore." For a while
he taught medicine and philosophy at Ispahan; then he settled at Teheran. He was even more
famous in medicine than in philosophy, though he added little to Galen. From the twelfth to the
seventeenth century, he was used in Europe as a guide to medicine. He was not a saintly character,
in fact he had a passion for wine and women. He was suspect to the orthodox, but was befriended
by princes on account of his medical skill. At times he got into trouble owing to the hostility of
Turkish mercenaries; sometimes he was in hiding, sometimes in prison. He was the author of an
encyclopædia, almost unknown to the East because of the hostility of theologians, but influential
in the West through Latin translations. His psychology has an empirical tendency.
His philosophy is nearer to Aristotle, and less Neoplatonic, than that of his Muslim predecessors.
Like the Christian scholastics later, he is occupied with the problem of universals. Plato said they
were anterior to things. Aristotle has two views, one when he is thinking,