The Causal Interpretation of Quantum Mechanics (CIQM) was in the first place described by historians as a consequence of the growing influence of Marxism among physicists in Western countries. Indeed, during the 1950s, the core of the group of physicists involved in the Causal program around Jean-Pierre Vigier and Louis de Broglie at the Institut Henri Poincaré was mainly constituted either of members or sympathizers of the PCF. Their works were strongly influenced by critics from Soviet Union against the mainstream interpretation of Quantum Mechanics, the so called « Copenhagen » interpretation. Vigier deplored the abandonment of scientific realism in favour of pragmatism he considered in great part responsible for the crisis in fundamental physics, such as the problem of renormalization. They also put the issue of the interpretation of the theory inside the PCF and created a controversy inside the party which raised the relationship between Marxism and science.
The theory was also part of a more global research program linked with contemporary questions in physics. This point is often forgotten which leads to the erroneous conclusion that the motivation of the IHP group was only ideological and, therefore, their activity was out of science. As early as 1957, in collaboration with Japanese physicists, the group proposed a theory for elementary particles and a method of their classification, in a period in where a standard theory was still missing.
This talk will particularly emphasize the close relationship between metaphysical thought and scientific practice, in what I call the putting in equations of scientific realism, through three concrete examples: the demonstration of the Born’s rule within the framework of the CIQM which lead to a general epistemology, proposed by Bohm and Vigier, called the Theory of levels of organization of nature; the model of extended particles and their classification and, as a synthesis, I will specify the non-trivial signification of a maintenance of classical pictures in Quantum Mechanics.