Disciple of al-Farabi, born in Saragosa. He is remembered mainly for his political philosophy. Unlike al-Farabi, he thought the philosopher could attain the highest point of human wisdom without living in a virtuous city, i.e. while solitary. All existing human society is imperfect, which is why cities need doctors, judges, and so forth, but they also need ‘weeds’ or idiosyncratic thinkers, among which might be those who followed the solitary life of perfection.