SummaryThe paper defends a theory of mind according to which certain sorts of acts arereal material relationsand compares this theory to causal theories of reference and perception. All mental acts are dependent for their existence upon the subject (person, organism) whose acts they are. Relational acts are dependent also on intended objects in the world. The relational theory thus implies a rejection of the Cartesian thesis to the effect that we could in principle have exactly the same thoughts even though the objects of these thoughts did not exist. It implies thereby also a rejection of Husserlian phenomenology. Husserľs earlier work on the formal ontology of part, whole and dependence nevertheless provides a framework which can allow a precise formulation of the relational theory