This article examines the historical transformation of the concept of ethics through a historical-conceptual analysis of key turning points from Classical Antiquity to Modernity. It argues that in classical philosophy, particularly in the works of Plato and Aristotle, ethics was understood as the rational inquiry into the common good and maintained structural autonomy in relation to historical customs and positive normativity. In the context of the Roman republican crisis, Cicero advanced a strategic integration of nature, reason, and law by identifying lex with recta ratio naturae. This politically motivated formulation reduced the conceptual space within which ethics could function as a critical standpoint independent of normative systems. The article further argues that this integration was consolidated in the medieval tradition, especially in Augustine and Thomas Aquinas, and later secularized in modern philosophy by thinkers such as Hobbes and Kant, thereby reinforcing the structural identification of ethics with normativity. Against this background, the article distinguishes between normative autonomy, understood as the primacy of reason over external sources of obligation, and structural autonomy, defined as the logical priority of the inquiry into the common good over the formulation of any rule of conduct. It concludes that recovering this structural distinction is a necessary philosophical condition for reconstituting the rational autonomy of ethics in contemporary debates.
Xiko ACIS (Mon,) studied this question.