Abū Bakr Muḥammad ibn Yaḥyà ibn aṣ-Ṣā’igh at-Tūjībī ibn Bājja (Arabic: أبو بكر محمد بن يحيى بن الصائغ التجيبي بن باجة), known simply as Ibn Bajja (Arabic: ابن باجة) or his Latinized name Avempace (/ˈeɪvəmpeɪs/; c. 1085 – 1138), was an Arab polymath, whose writings include works regarding astronomy, physics, and music, as well as philosophy, medicine, botany, and poetry.
He was the author of the Kitāb an-Nabāt ("The Book of Plants"), a popular work on botany, which defined the sex of plants. His philosophical theories influenced the work of Ibn Rushd (Averroes) and Albertus Magnus. Most of his writings and books were not completed (or well-organized) due to his early death. He had a vast knowledge of medicine, mathematics, and astronomy. His main contribution to Islamic philosophy was his idea on soul phenomenology, which was never completed.