Kant was on a roll. He turned to writing his professorial thesis or habilitationsschrift, the Physical Monadology (1756).  Have established the fundamentality of “the between” for both free events and mechanical causality (and their compatibility), Kant then turns to discuss what the “between” means with regard to the structure of matter—the physical manifestation of forces. Material things are extended—they take up space. The terminal units of nature must be point-entities, for if they weren’t, they would be further divisible and not be the final constituents.  Ontology suggests that spatial objects consist of final elements. Logic requires that final elements are indivisible, hence points. Geometry warns that points never fill a volume, regardless how many are used. So how can points make up the spatial things in nature? On the matrix-level, what happens “between” the points?