Developments in the historiography of science force the historian, interested in the influence a philosophy has on science, to make clear in what scientific aspect he expects to find this effect. The treatment of the issue up to now implied that the decision examine the specific philosophy — an organized way of thinking — as a sensitizing agent of the scientist's mind which enabled him to perceive and recognize a phenomenon. The analysis implied that the mechanism producing the phenomenon, the laboratory habits (theoretical and technological), remained unchanged.