In order to create a good flakey pastry, make effective concrete, fight soil pollution or accomplish any one of our daily tasks, we must discover the right " recipe " ; that is, in order to achieve our goals, we must implement the correct ratio of ingredients and it is only by this correct distribution that we achieve success. Due to people's diverse needs, we must rely on scientists, engineers and craftsmen to discover the right " recipes " in creating eclectic mixtures. Yet the mechanisms used are often so complex that they are impossible to explain scientifically and therefore do not fit in nicely in the physical world and are classified as belonging to the inexplicable world of chaos. Étienne Guyon and Jean-Pierre Hulin show us how we can have a whole new philosophical outlook on daily life.
Étienne Guyon is the director of the École normale supérieure. Jean-Pierre Hulin is the director of research at the National Science Research Council (CNRS).