 Israeli’s description mirrors the list of al-Jahiz (d. ca. 869) in the Book of Indications and Considerations (Arabic: Kitab al-Dala’il wa’l-cItibar) as well as cAli ibn Sahl Rabban al-Tabari (fl. 9th century), in his medical text Firdaws al-Hikmah fi al-Tibb. His list varies slightly from that of al-Kindi, who in his treatise on metaphysics Al-Falsafah al-cula defines the third inquiry as which, rather than how.