The specific problems of consent for the mentally incompetent are reviewed. Scientific research is essential to test the validity of present treatments and to develop new ones. The respective roles of the physician and the researcher have to be clearly defined. The vulnerability of psychiatric patients has to be taken into consideration in such a way that some research can be conducted. It is emphasised that the ethical restrictions for research, although highly justified and necessary, are in part responsible for (...) the relatively slow progress in the application of modern neurosciences to psychiatric diseases. (shrink)

Analogy plays a basic part in engineering which is subject to certain limitations, due to the following reasons:— lack of accuracy of the measuring instruments and of computing data; — simplifying assumptions necessary for establishing the mathematic model; — restrictions due to compulsory computation means and time. The basic criterion of engineering knowledge is efficiency. The engineer works thus on successive approximations, each of them corresponding to a more or less appropriate model of the final result. In order to avoid (...) disappointment, it is very important for him to be conscious of the relativity of his knowledge and of the scope of teh successive approximations. This procedure is the same for other fields of knowledge and provides an opportunity to specify the concept of rigour applying to each. It shows the practical, limited and revisable character of any knowledge not springing from metaphysics. (shrink)

RÉSUMÉDifférentes méthodes ?identification des systèmes ont été développées par les informaticiens qui consistent à déterminer à partir de ľobservation des grandeurs ?entrée et de sortie de ce système, les relations de cause à effet qu'il établit entre ces grandeurs.Cet exposé rappelle le principe des méthodes ?identification 〈statique〉 et 〈dyna‐mique〉, et conclut que ces méthodes peuvent être considéréd comme un exemple ?applications des approches définies par la philosophic de ľouverture pour ľacqui‐sition de nouvelles connaissances.