Avicenna (Persian name, Ibn Sina; 980–1037) was a child prodigy who had memorized the Koran by the age of 10. As an adolescent, “he had read Aristotle’s Metaphysics forty times and could prac- tically recite it by heart” . He became a physician before he was 20, and as a young man was considered the best of the Muslim physicians. He wrote books on many topics, including medicine, mathe- matics, logic, metaphysics, Islamic theology, astron- omy, politics, and linguistics. His book on medicine, The Canon, was used in European universities for more than five centuries. In most of his work, he borrowed heavily from Aristotle, but he made modifications in Aristotle’s philosophy that persisted for hundreds of years.
In his analysis of human thinking, Avicenna started with the five external senses—sight, hear- ing, touch, taste, and smell. Then he postulated seven “interior senses,” which were arranged in a hierarchy. First is the common sense, which syn- thesizes the information provided by the external senses. Second is retentive imagination, the ability to remember the synthesized information from the common sense. The third and fourth are compos- itive animal imagination and compositive human imagination. Compositive imagination allows both humans and animals to learn what to approach or avoid in the environment. For animals, this is a strictly associative process. Those objects or events associated with pain are subsequently avoided, and those associated with pleasure are subsequently approached.