Matthieu Fontaine obtained his PhD in Philosophy at the Université Lille 3 – Charles-de-Gaulle (France), in 2013. In his PhD dissertation (supervised by Sh. Rahman), he advocates an artefictual theory of fiction for which he defines a dialogical semantics as well as a formal semantics for relations of ontological dependences. From 2007 to 2010, has taught various topics in philosophy and logic at the faculty of philosophy of Lille. From 2011 to 2013, he has taught logic, argumentation and philosophy of science at the faculty of medicine of Lille. From 2013 to 2015, he has been postdoctoral researcher at the Institute of Philosophical Investigation – National Autonomous University of Mexico, where he worked on the ontology of hypothetical objects and the use of existential conjectures in abductive reasoning with Dr. Ana Rosa Perez-Ransanz and Dr. Atocha Aliseda. Matthieu Fontaine is currently FCT-Post-doc at CFCUL and work on a dialogical logic approach to the use of existential conjectures in abductive reasoning. His researches are also related to ontological and metaphysical matters, in particular about hypothetical and fictional entities. He is interested in Hintikka’s philosophy, too. s editor with Shahid Rahman (Lille, France) and Nicolas Clerbout (Valparaiso, Chile) of the collection « Dialogues and the Games of Logic », College Publications, London.