Suspended in a pitch-black void with no sight, sound, or sensation, would you still know that you exist? That sensory deprivation thought experiment, known as the floating man, was devised in the eleventh century by Ibn Sina, the Persian polymath known in the West as Avicenna. This episode traces his life from a prodigious childhood near Bukhara, where he memorized the Quran by ten and learned Hindu-Arabic numerals from an Indian greengrocer, to becoming physician to the Samanid ruler at seventeen and a political refugee when that empire collapsed around 999 CE.

We follow him from court to court, including a grueling journey to Gorgan only to find the ruler had died, his forced service as vizier under Shams al-Dawla, his months in hiding writing fifty pages a day of The Book of Healing, and his four-month imprisonment in a fortress. Along t ...