Reference by Occurrence

In the literature on Euler diagrams, both classical and contemporary, it has sometimes been claimed that free rides emerge because of certain “spatial properties” of this system of representation. In this paper, I argue that this claim is insufficient. I show that a variety of Euler diagrams is possible in which the spatial conditions for the emergence of free rides are met but in which free rides do not emerge. This implies that another condition has to be met in order to have free rides, which I call “reference by occurrence” or “occurrence-referentiality”.