if cognitive growth presuppose that no element is indissolubly linked a priori to any other, and that everything is open to rethinking, then economic and productive growth requires exactly the same of human activities and hence of human roles. Roles become optional and instrumental. The old stability of the social role structure is simply incompatible with growth and innovation. Innovation means doing new thing, the boundaries of which cannot be the same as those of the activities they replace. No doubt most societies can cope with an occasional re-drawing of job specifications and guild boundaries, just as a football team can experimentally switch from one formation to another, and yet maintain continuity. One change dose not make progress. But what happens when such changes themselves are constant and continuous, when the persistence of occupational change itself becomes the one permanent feature of a social order?