 Leibniz wants to rule out any kind of causation in which one substance passes something on to the other substance: “The way of influence belongs to that of the common philosophy. However, since it is impossible to conceive of material particles or of species or immaterial qualities that can pass from one of these substances into the other, the view must be rejected” (GP iv, 498f). Early in his career, Leibniz dismisses the physical influx theory of the Scholastic Francisco Suarez as a “barbaric expression … metaphorical and more obscure than what it defines” (Preface to an Edition of Nizolius GP iv, 150). (Whether Suarez actually held the view Leibniz ascribes to him is another matter entirely.) Moreover, the pre-established harmony can achieve the same effect without the metaphysical baggage of “property passing”: “So there will be a perfect accord between all these substances which produces the same effect that would be noticed if they all communicated with each other by a transmission of species or of qualities, as the common run of philosophers imagine” (New System GP iv, 484/L 457f).