 Chapters four to seven on the parts of the soul place Bacon in the context of the Franciscan and Dominican arguments on the parts of the soul. These chapters show that Bacon was very active in the early debates at Paris in which the unity of substantial form in Aquinas was strongly criticized by the Franciscan School. Bacon is so critical of Aquinas’s position that he deems it heretical. He defends the notion of plurality of forms while strongly arguing for the essential substantial unity of the human being. Bacon also uses his remarks to let the reader know that his study of Perspectiva was undertaken to criticize the common teaching on natural philosophy (including psychology) and medicine at the University of Paris.