The debate is in part about the importance we should attach to a significant (but not radical) development of the written instrument in France between 980 and 1030 or between 1020 and 1060, that is to say, in a country and at a period when it did not yet have the major social role it acquired in the thirteenth century.(3) But the principal disadvantage of the "mutationist
" thesis, in my view, is that it retains notions which are too vague or inappropriate, such as the opposition between public and private, and "feudal society"; it thus invites the peremptory challenge to any idea of medieval society made by the hyper-Romanist "school" (Jean Durliat, Elisabeth Magnou-Nortier, even, to some degree, K.
New species must, therefore, arise by a discontinuous process, which DeVries named "mutation." This could then be acted upon by natural selection within limits, but the mutationists
denied that natural selection could operate in the way envisioned by Darwin.