In their essay which appeared in 1972 in Models in Paleobiology, Stephen Jay Gould and Niles Eldredge, introducing the theory of punctuated equilibrium, stressed the fact that no scientific theory develops as a simple and logical extension of facts and of patiently recorded observations, and that the particular vision of the world that the scientist adheres to is able to influence, even unconsciously, the way in which data are collected, selected and then interpreted. Scientists, being aware of the existence of an intrinsic problem of prejudice in their scientific research activity, know that, in order to produce original and innovative ideas, it is fundamental to try to revolutionise their research image, to look at reality in a new light, to read data with alternative viewpoints.