ABSTRACT
The aims of this chapter are: to discuss the scope and limitations of the main argument for scientific realism; to spell out some more discriminating criteria for the existence of theoretical entities than this argument provides; and to use these criteria to elaborate and defend a sophisticated realist ontology for science. The ontology of scientific realism is supported by an argument from the best explanation: if the world behaves as if entities of the kinds postulated by science exist, then the best explanation of this fact is that they really do exist. Properly understood and used, this is a good and powerful argument. To determine the scope of the main argument for scientific realism, people must distinguish clearly between those entities that are supposed to be involved in causal processes and those that are not. The main argument for scientific realism requires us to be realists about physical properties and relationships as well as about forces.
