Constitutivism and Kantian Constructivism in Ethical Theory: Editorial Introduction Christoph Hanisch 1 & Sorin Baiasu 2 Received: 26 July 2016 /Accepted: 26 July 2016 # Springer Science+Business Media Dordrecht 2016 Abstract The introduction summarizes the main arguments formulated in the six papers of this special issue on Constitutivism and Kantian Constructivism in Ethical Theory. We highlight the unifying theme addressed in the essays, i.e., the question of whether constitutivism is able to fulfill the promise of providing an account of normativity starting from relatively slender assumptions, including the avoidance of realist presuppositions. Keywords Immanuel Kant . Chrisitine Korsgaard . Constitutivism . Constructivism . Practical reason . Agency The ambitious project constitutivism has proposed is that of vindicating the phenom- enon of normativity on the slim basis of an analysis of what agents do, insofar as they count as practically deliberating and as performing actions. The constitutivist claim is that practical normative principles are constitutive of action and agency, and a proper Philosophia DOI 10.1007/s11406-016-9743-6 The six essays in this special issue were initially presented at the European Consortium for Political Research (ECPR) General Conference that took place at the University of Glasgow in September 2014. The papers collected here are revised versions of what was presented and discussed there under the aegis of the ECPR Standing Group on Kantian Political Thought. The final versions are the result of a double-blind peer review and selection process. We want to thank Asa Kasher, Editor in Chief of Philosophia, the authors, and the referees for their contributions and for their patience concerning the editorial proceedings. We are also indebted to the ERC Advanced Grant BDistortions of Normativity^ for supporting our work on this publication project. * Christoph Hanisch hanisch@ohio.edu Sorin Baiasu s.baiasu@keele.ac.uk 1 Department of Philosophy, Ohio University, Ellis Hall, Rm 202, Athens, OH 45701, USA 2 Philosophy Programme, School of Politics, Philosophy, International Relations and Environment, Keele University, Keele ST5 5BG, UK