Qualifying and quantifying medical uncertainty in 10th-century Baghdad: Abu Bakr al-Razi

Abu Bakr Muhammad ibn Zakariya’ al-Razi (d. 925) was one of the most interesting and innovative clinicians of the medieval world.1 He distinguished smallpox from measles, experimented on an ape to establish the toxicity of quicksilver (mercury) and used a control group to assess whether bloodletting was an effective treatment for ‘brain fever’.2–5 Al-Razi stated in one of his treatises: My aim and objective is [to provide] things useful to people who practise and work, not for those engaged in research and theory5 (pp. 112–13). Hospitals in 10th-century Baghdad Al-Razi rose to become a hospital director both in Rayy (his home town, and now a suburb of Tehran) and Baghdad. This hospital environment proved important for his medical research. By the 10th century, hospitals in Baghdad had developed into quite sophisticated institutions. For instance, in the 920s and 930s, a powerful vizier by the name ‘Ali ibn ‘Isa endeavoured to improve public health, both by maintaining hospitals and sending doctors to areas where there was inadequate medical provision. The hospitals were Islamic charitable foundations with sometimes substantial endowments, so they benefitted from both legal and financial security; but ‘Ali ibn ‘Isa specified that they should serve non-Muslims as well as Muslims.6 Moreover, the medicine practised in these hospitals was not based on religious beliefs, but on the humoral pathology inherited from the Greeks, as the writings of the hospital physician al-Kaskari demonstrate.7 In this sense, the Islamic hospitals offered – somewhat paradoxically – a non-religious and non-sectarian service: physicians and other practitioners from various backgrounds catered for equally diverse patients in a non-confessional medical system. The development of the hospitals meant that elite medicine moved to them, and some of the most highly regarded doctors looking after patients in the upper echelons of society worked and taught in them. In addition, given their large numbers of patients, hospitals provided an infrastructure for research.