 The ground floor (so to speak) is the atomic level that is occupied by a “multitude” of simple substances. Unlike simple substances at the nominal level of reality that lack the “mode of existence”, simples at the atomic level are real individuals (i.e., complete and determinate, actually existing beings). In addition to the term “simples”, Wolff also refers to these occupants of the atomic level as “elements” and “atoms of nature” (atomi naturae). Atomic elements (as such) are conceived by Wolff to be “unextended points of force” that lack internal motion (motus intestinus) but yet remain in a constant state of change. Each atomic element is defined, or individuated, by its own distinctive internal state and each is considered to be indivisible in-itself. Although later Wolffians, such as Baumeister, would eventually refer to Wolff’s atomic elements as “monads”, there is at least one important respect in which Wolff’s atomic elements are different from Leibniz’s monads (Baumeister 1747: 226). Leibniz conceives monads as simple unextended substances, and hence Leibnizian monads are “windowless” substances that do not interact or influence one another. Wolff’s atomic elements, in contrast, do interact and have real dynamic influence over each  other.[4] 