Abstract
In this paper, I try to argue that both science, as a specific kind of knowledge, and human knowledge in general are activities of constructing models. In the first part, I present my conception according to which scientific models are abstract entities, and that scientific theories may be interpreted as classes of models as abstract replicas of real settings, in which certain laws apply. In the second part, I try to extend that same conception to ordinary human knowledge, particularly to the case of the cognitive activity of classifying objects of experience