“…We leave open what is the exact nature of both properties (relations) and states. In an ontological perspective, see Section 6, states can be seen as real entities that are part of the world, e.g., facts, instantiations of universals (see Armstrong (1989)) by objects, or tropes (see Daly (1997); Maurin (2014)). In an epistemological perspective, see Section 7, states reduce to observations, i.e., empirical or cognitive classifications of objects under (qualitative Masolo et al / The interplay between models and observations or quantitative) concepts (see Margolis and Laurence (1999)) that result from measurement, testing, perceptive, cognitive, or analytical processes.…”