In this study the notion of mechanistic entities is analyzed as it has been conceptualized by Hermann Lotze in his article Life. Vital Force (1842), the metaphysical foundation of which has recourse to his Metaphysik (1841) and Logik (1843). According to Lotze, explanations in the sciences are arguments which have a syntactic and a semantic structure—similar to that which became later known as the DN-model of explanation. The syntactic structure is delineated by ontological forms, the semantic by cosmological ones; the (...) latter comprise the preconditions for the construction of appearances in accord with the ontological forms. Mechanisms are embedded into this logical framework by representing the more complex spatio-temporal arrangements of cosmological entities. The coordinated model of a mechanism is a reductive type of explanation. This study also demonstrates how Lotze made use of his concept of mechanisms in order to explain law-like and probabilistic events in organic and inorganic nature, thereby establishing an original ‘oligomeric’ (i. e., a fraction of the parts of a system determines its development) variant of a preformative theory of ontogenesis which anticipates modern concepts of genetic determination. In this context, Lotze alludes to paradigms of dissipative structures. The relevance of these reflections for subsequent theories is shown by contrasting them with Schrödinger’s theory of organisms. Finally, a comparison of some aspects of Lotze’s concept of mechanisms with equivalent aspects of current normative approaches confirms that essential elements of the latter versions can be retrieved in the former one. Above that, Lotze employs the teleological aspect of ontological forms in order to determine the extent of the mechanistic system under consideration. He further differentiates three modal states of mechanisms and includes a concept to explain exceptions or irregularities. The concept of ‘activity’ is strictly excluded from his account and shown to be a metaphysical illusion. (shrink)