Reflections or Dialogicals: Ways for Making up an Ethics. This purpose of this article is to analyze the relationship between reason and ethics in the thoughts of Léon Brunschvicg and Gaston Bachelard. It will demonstrate that although the positions of these two authors have points in common as far as the development of their philosophical trajectories, there are also profound divergences in regards to their ethical conceptions. In affirming the passage from intellectual reason to moral consciousness, the ethical humanism of Brunschvicg takes as foundation a monological conception of reason. In showing that the constitution of ethical principles is modeled after the dialogical nature of the scientific city, Bachelard opts for a conception of reason and ethics that passes thorough a reflection on the path taken by man, a path filled with contradictions, but that it is nonetheless as true as the one established by Brunschvicg.