If we wish to speak of the widening of the idea of causality, we must first specify the exact meaning of this concept, the modification of which is now being considered by many contemporary philosophers and scientists. In order to shed light on the classical concept of causality, it is almost impossible to avoid approaching it from the genetic point of view. Without a historical perspective we have only a very limited understanding of the content of the classical concepts by which this philosophic as well as scientific tradition has been constituted. By showing the deep and tenacious roots of our belief in rigorous determinism, we shall better understand certain types of resistance which today are opposed to any attempt at making determinism more flexible.