Abstract: In confirmation of the conclusions of Ch. 11, examination of the principal relevant texts from the period 1685–1704 shows that Leibnizian primary matter is not an ultimate substratum or subject of properties, but only an aspect of, and abstraction from, such a subject or substance. Specifically it is the passive principle in the essence or primitive force of an unextended, perceiving substance, and all its operations are aspects of the perceptual operation of the substance.

Keywords: abstraction, aspect, essence, Leibniz, perception, primary matter, primitive force, substance, substratum,