In "The ethical dilemma between economics and ecology. Epistemological considerations", relevant aspects in the evolution of economics as a science, and its intrinsic links with the natural sciences, technology, epistemology and ethics are presented. In a journey through classical and neoclassical economics, political economy, economic neoinstitutionalism, and old and new paradigms, such as sustainable development and economic degrowth, their postulates are contrasted with the inescapable Law of Entropy, in order to extract, without prejudice, what has been considered the best of each current of thought. Likewise, the need for an epistemological and paradigmatic synthesis is raised, which rescues the role of ethics in human beings-nature relations, in order to proceed in a truly rational and responsible manner. An alternative model is proposed: the Bioeconomic Model (MBEC), whose pillars are based on ethics and the Law of Entropy.