Informatics and AI claim, at least implicitly, that the world is made of objects organized into classes (taxonomies, ontologies...). In this paper, we explore another idea: we structure our material relationships by collecting objects within collections, which are never as static as classes. The notion of collection will appear as an efficient way to articulate organic life and conceptual life throughout a metastable equilibrium, more promising than the intensive categorization traditionaly made in informatics, as far as depicting and managing human experience is concerned.