[Medicine as a science of actions: consequences for psychiatry].

The need for a theory is grounded on the heterogeneity of medicine: of basic situation, of medical subsystems and of praxis. The relationship between theory and practice in medicine should be considered as a task of theoretical reflection, beyond contexts, application and orientation. As a theory of theories--metatheory--its model lies closer to that of "action sciences" than of "object sciences", considered as paradigmatic forms of medicine. The relevance of these concepts to psychiatry is illustrated on the basis of the influence of behavioral sciences upon biomedicine, whose advancement rests with psychiatry.