It has often been noted that a kind of double dynamics char- terizes the development of science. On the one hand the progress in every discipline appears as the consequence of an increasing specialization, implying the restriction of the inquiry to very partial fields or aspects of a given domain. On the other hand, an opposite (but one might better say a complementary) trend points towards the construction of theoretical frameworks of great ge- rality, the aim of which seems to correspond not so much to the need of providing -explanations- for the details accumulated through partial...