**Richard de Rozario**

The Hunt Lab for Intelligence Research, The University of Melbourne, Parkville, VIC 3010, Australia; richard.derozario@unimelb.edu.au

Received: 19 May 2019; Accepted: 15 July 2019; Published: 18 July 2019

**Abstract:** Applied ontology, at the foundational level, is as much philosophy as engineering and as such provides a di fferent aspect of contemporary natural philosophy. A prominent foundational ontology in this field is the Basic Formal Ontology (BFO). It is important for lesser known ontologies, like the trope ontology of interest here, to match to BFO because BFO acts like the glue between many disparate ontologies. Moreover, such matchings provide philosophical insight into ontologies. As such, the core research question here is how we can match a trope ontology to BFO (which is based on universals) and what insights such a matching provides for foundational ontology. This article provides a logical matching, starting with BFO's top entities (continuants and occurrences) and identifies key ontological issues that arise, such as whether universals and mereological sums are equivalent. This article concludes with general observations about the matching, including that matching to universals is generally straightforward, but not so much the matching between relations. In particular, the treatment of occurrences as causal chains is di fferent in the trope ontology, compared to BFO's use of time arguments.

**Keywords:** ontology; BFO; tropes; applied philosophy
