Abduction and the Scientific Realist Case for Properties

Traditionally, many arguments for realism about properties (universals or tropes) rely on a priori claims. The author argues that if we make use of an abductive principle that is commonly employed by scientific realists, a new argument for property realism can be formulated which is based firmly in scientific practice. The abductive principle says that we should believe in the existence of certain theoretical entities if they figure in the best explanation for what scientists observe. The scientific argument for property realism then says (roughly) that the best explanation for various behavioural patterns that physical scientists observe is that microscopic entities (such as electrons) instantiate stable, causally efficacious properties. After presenting the argument, the author defends it against possible objections. More generally, the article provides a case study for how science and metaphysics can work together to generate ontological claims.