*This text is only available in German.*

In *Geometry and Monadology* (2007), Vincenzo de Risi discusses the connection between Leibnizian Metaphysics and Geometry. In Chapter 3: *Phenomenology*, De Risi derives necessity of space from the existence of the, inter-related, monads. These spiritual entities are both *receptive* and *expressive*. The spatial world of phenomena consists of those expressions according to the inter-monadic relations. Conversely, plurality of perceptions is just the individuation principle for monads: each monad is determined by their inner and outer perceptions.

We explain de Risi’s Model for expressivity of monads, which is founded on universal algebra. Perceptions and expressions are implemented as relations and homomorphisms. As an advantage this formalization clarifies many key arguments and principles from the *Monadologie*.

After laying the algebraic foundations, we consider the expressive relation between the noumenal world of monads and the phenomenal world of perceptions. We discuss the limits of finite perception as well as material limits of the expressive relation. Finally we compare the results on perceptions gained from the algebraic model with the ones on Leibniz’ theory of knowledge.

Conclusively, we put the foundational thoughts behind this phenomenology in contrast to concurrent metaphysical theories.

De Risi’s Algebraic Model for a Monadic Phenomenology