إخوان الصفا
Ibn Miskawayh's "al-Fawz al-Asghar" and the Brethren of Purity's "Encyclopedia of the Brethren of Purity" ("The Epistles of Ikhwan al-Safa") developed theories on evolution that possibly had an influence on Charles Darwin and his inception of Darwinism, but has at one time been criticized as overenthusiastic.