Abstract
Is there an ontological question relative to van Fraassen’s Constructive Empiricism? It seems so, despite this philosophical position, a reference for contemporary Empiricism, presenting itself as an epistemological thesis. It is, furthermore, a very up-to-date matter, as the Dutch philosopher has recently changed his mind about the possibility for us to observe common optical phenomena as the rainbow. This reveals the necessity for a discussion about the concept of phenomena as used by van Fraassen, as Foss stated more than twenty years ago, but also – and this is an intertwined question – about what ontology is assumed by Constructive Empiricism.