ABSTRACT
Latin Western tradition of natural philosophy built on Aristotelian views, nature's regularity that it occurs always or most of the time was an uncontroversial part of the definition of nature. Voluntarism indeed goes a long way towards explaining the contours of philosophies of seventeenth-century thinkers like Gassendi, but it must be noted that not all voluntarists or nominalists believed in the use of natural philosophy; nor were their natural philosophies identical. Philip Melanchthon wrote two textbooks on natural philosophy that was used widely across Europe: the Commentarius de anima and the Initia doctrinae physicae. Johannes Magirus studied at Padua under Jacopo Zabarella and Archangelus Mercenarius, and took his doctorate in medicine from the University of Marburg in 1585, after which he spent some time at Fritzlar until 1591, when he became the professor of natural philosophy at Marburg. Natural philosophy had been taught continuously at Marburg since 1533.
