Abstract
This article first offers a simplified version of a universal ontology, conceived as a general framework for description of the material and mental world. It analyzes the notions of entity, property, relation and temporality and their joint development in terms of relationship between parts and whole or else of emergence of a new entity. It illustrates the preceding principles as concerns economic science, for which the entities are the agents, the goods and the institutions. It then insists on the coupling the latter achieves between physical and psychological properties as well as the reasoning it proposes in terms of equilibrium and more recently learning.