 He appears to have enjoyed a favorable reputation, and is described by Bernard of Besse as a professor of great fame for holiness and learning, whose writings were both solid and extremely useful.The main aim of the "Summa de anima" is to set out Jean's position on being and essence in the context of the debate between those who defend the theory that all of created being is composed of matter and form, and those who, like Thomas Aquinas later would, rejected the doctrine which attributed a composite nature to the soul.Jean investigates the soul according to the four Aristotelian causes