[Biology yesterday, today and tomorrow].

Throughout the history of the biological disciplines from the 18th to the 20th centuries, there has been a succession of predominating fields of interest: morphology, physiology, genetics, biochemistry, ecology and ethology, while statistics, biometry and computer sciences were developing as powerful means of imposing rigor on research. In all sciences, there is a fundamental empiricism which has often been criticized as prescientific. However, it is unavoidable, especially in biology owing to the unusual wealth and complexity of the facts to be reported. Explaining in the natural sciences first requires the discovery of relationships between facts. Biological explanation has many levels. One of the main avenues leading to true explanation is the multidisciplinary approach, which is in reality an attempt at synthesis. Another characteristic of biological work is the equilibrium between pragmatism and idealism, usually expressed as a balance between application and theory. Both modalities are necessary because of their complementarity. The emergence of ecology demonstrates this duality in the recent past. The equilibrium between theory and application should be decided by the biologists themselves, not by the funding public agencies, although competent administrators are necessary for the welfare of researchers. Applied and theoretical research should be kept separate to a large extent, even though they remain interdependent. In biology, theoretical work has suffered considerable neglect as compared to the situation in physics and chemistry. Biology has few explanatory theories and the few it possesses have often been put forward by physicists in the field of biophysics.(ABSTRACT TRUNCATED AT 250 WORDS)