Middle-range nursing theories are necessary for the advancement of the discipline

This article tries to discuss general aspects on models of nursing knowledge, basic elements for its development and practice. First, it shows the importance of the development of knowledge sustained by the practice and the expression of it by means of four knowledge models: empirical or nursing science, ethical, esthetical or nursing art, and personal. A description of each model of knowledge takes place, beginning with the personal one. Its meaning is showed as something basic for the development of ethical and aesthetical models, as it is a condition sine qua non such models are not totally developed or expressed satisfactorily in practice. It presents the discussion on evolution of epistemological questions toward philosophy and ontology. It tries to progress in the knowledge of the self or essence of what is known, to end with a summary on repercussions of knowledge models inclusion in syntax of nursing discipline