Abstract
This essay presents a model of a scientific field, as constituted by a domain of objective phenomena and a community of practitioners, interfaced by laboratory instrumentation and machinery. The relations between items in the domain, as well as those between the cognitive tools (concepts, statements, problems, classifications) that shape the practices of the community are postulated to be relations of exteriority, that is, relations that do not determine the identity of what they relate. This move allows the model to avoid holism. The essay then goes on to contrast the proposed model with Kuhn holistic theory of paradigms to highlight its advantages.