Even though as a group merchants were inclined to keep to themselves and, jealous as much of their markets as of their privileges, were unwilling either to share the first or to allow the second to be diluted, they always left open the possibility of penetration from outside. Both at the margins of the group and within its inner divisions, there was in effect a two-way process of osmosis unimaginable in the hidebound world of the shop and the workshop. If we look at the destinies of some exceptional figures in this world, it is tempting to imagine a genuine fluidity among social classes. But in reality, all social developments reflect a balance between the natural ossification of all social structures and the dynamism inherent in individuals or the economic climate.
The structural constraints that confined and divided the petite bourgeoisie were not there simply for protection. Because the closing of ranks was seen by those who were the first to be established as an appropriate response to the threats posed by newcomers, the weaver, pewterer, or baker took refuge in a social rigidity that eventually overcame his whole outlook. An inscription scratched with a knife point on the wall of the Palais de la Cité, under the portrait that Enguerran de Marigny, Philip the Fair's minister, had painted of himself on the stairway leading to the great hall, draws the moral from the too rapid rise and subsequent spectacular fall of the great:
Chacun soit content de ses biens,
Qui n'a suffisance n'a rien.