ABSTRACT
The purpose of this section is to present a very general orientation for those readers unfamiliar with Kuhn's theory; the two following sections, on Bloom and Derrida, have a similar purpose. Probably in most cases readers who are quite knowledgeable about the topics will be thoroughly acquainted with only one of the three figures, as they do belong to separate specialities. In any case a general orientation makes subsequent detailed and advanced discussions more intelligible.
