I have purposely limited myself to a rather brief statement in this introduc tion, in order that the summing up be not misrepresented for the discursive development of the whole. There is something more than mildly dangerous in setting oneself a series of goals in an introduction only to find them happily attained in the conclusion, as if getting from the beginning to the end was simply a question of transition. Of course, the destination of a speculative presentation includes the process of development in such a way that the end is always implicitly the beginning: each configuration simply...