To a first approximation, ontology is concerned with what exists, metaontology with what it means to say that something exists. So understood, metaontology has been dominated by three views: (i) existence as a substantive first-order property that some things have and some do not, (ii) existence as a formal first-order property that everything has, and (iii) existence as a second-order property of existents’ distinctive properties. Each of these faces well-documented difficulties. In this chapter, I want to expound a fourth theoretical (...) option, which unfortunately has remained ‘under the radar.’ This is Franz Brentano’s view, according to which to say that X exists is not to attribute a property at all (first- or second-order), but to say that the correct attitude to take toward X is that of accepting or believing in it. (shrink)