is known. It is the science of logic.... [It is also] concerned with the different kinds
of valid, invalid, and near valid inferences.”^5
Despite its political disunity, then, the Islamic world of the tenth and eleventh
centuries remained in many ways an integrated culture. This was partly due to the
model of intellectual life fostered by the Abbasids, which even in decline was copied
by the new rulers, as we have just seen. It was also due to the common Arabic
language, the glue that bound the astronomer at Córdoba to the philosopher at Cairo.
Writing in Arabic, Islamic authors could count on a large reading public.
Manuscripts were churned out quickly via a well-honed division of labor: scribes,
illustrators, page cutters, and book-binders specialized in each task. Children were
sent to school to learn the Qur’an; listening, reciting, reading, and writing were taught
in elementary schools along with good manners and religious obligations. Although a
conservative like al-Qabisi (d.1012) warned that “[a girl] being taught letter-writing or
poetry is a cause for fear,” he also insisted that parents send their children to school
to learn “vocalization, spelling, good handwriting, [and] good reading.” He even
admitted that learning about “famous men and chivalrous knights” might be
acceptable.^6
Educated in the same texts across the whole Islamic world, Muslims could easily
communicate, and this facilitated open networks of trade. With no national barriers to
commerce and few regulations, merchants regularly dealt in far-flung, various, and
sometimes exotic goods. From England came tin, while salt and gold were imported
from Timbuktu in west-central Africa; from Russia came amber, gold, and copper;
slaves were wrested from sub-Saharan Africa, the Eurasian steppes, and Slavic
regions.
Although Muslims dominated these trade networks, other groups were involved in
commerce as well. We happen to know a good deal about one Jewish community
living at Fustat, about two miles south of Cairo. It observed the then-common
custom of depositing for eventual ritual burial all worn-out papers containing the
name of God. For good measure, the Jews in this community included everything
written in Hebrew letters: legal documents, fragments of sacred works, marriage
contracts, doctors’ prescriptions, and so on. By chance, the materials that they left in
their geniza (depository) at Fustat were preserved rather than buried. They reveal a
cosmopolitan, middle-class society. Many were traders, for Fustat was the center of a
vast and predominately Jewish trade network that stretched from al-Andalus to India.
Consider the Tustari brothers, Jewish merchants from southern Iran. By the early
eleventh century, the brothers had established a flourishing business in Egypt.
