Hugh MacColl’s Ontological Domains

The most influential approach to the logic of non-existents is certainly the one stemming from the Frege-Russell tradition. One of the most important early dissidents was indeed Hugh MacColl. It is in relation to the notions of existence and arguments involving fictions that MacColl’s work shows a deep difference from the work of his contemporaries. Indeed, MacColl was the first to attempt to implement in a formal system the idea that to introduce fictions in the context of logic amounts to providing a many sorted language. The aim of the paper is to show that MacColl’s ontological domains make sense in the context of a new semantics for fictional operators developed in collaboration with Tero Tulenheimo (Lille3), where fictions are conceived as artifacts