AbstractA model of a set of interacting sectors is proposed. Dynamic equations governing the motions of sectoral productions are chosen. A supplementary equation establishing equilibrium of the national budget is obtained. The contradictory effects of technical change on the economic system are studied, as this change destroys employment by replacing men with machines and computers and also creates new sectors and employment. The paper studies a particular case of an economic system in which technical change globally destroys employment. Stimulation of the economic system can be done either by inducement to consumption or by inducement to production. In order to maintain total consumption and production, the paper shows that it is necessary to increase the purchase power of consumers and to create new sectors absorbing a lot of working hours per production unit. To obtain this, good quality products needing a lot of working hours must gradually replace all identical factory products needing less and less working hours.