In the wake of the publication of Forrester's World Dynamics and Meadow's The Limits to Growth-books which in The Netherlands may have received ex- cessive attention from the public at large-the Netherlands Organization for Applied Scientific Research (TNO) established a commission under the chair- manship of the late Professor R. Timman. The commission received the task of trying to find a sound philosophical basis for world modelling and to stimulate the building of models that incorporated those aspects of society which are usu- ally left out of mathematical models because of technical...