Abzj proposed, in a fragment established and translated herein, two methods to build a parabolic mirror. The lack of demonstration, particularly for the first method, raises a difficult question of interpretation. To understand this method, O. Neugebauer used, in an unpublished article translated herein, concepts of descriptive geometry. He then eliminated the space construction used, to keep only simple geometrical considerations known by the Greeks. The second interpretation, given by R. Rashed, is based on the geometrical practices of al-Bnhzj from (...) Ibn Sinān seems to support this last interpretation. (shrink)

The study begins with the language employed in and the psychological basis of thought experiments as understood by certain medieval Arabic philosophers. It then provides a taxonomy of different kinds of thoughts experiments used in the medieval Islamic world. These include purely fictional thought experiments, idealizations and finally thought experiments using ingenious machines. The study concludes by suggesting that thought experiments provided a halfway house during this period between a staunch rationalism and an emerging empiricism.