One aim of the physical sciences has been to give an exact picture of the material world. One achievement of physics in the twentieth century has been to prove that that aim is unattainable . . . . There is no absolute knowledge. And those who claim it, whether they are scientists or dogmatists, open the door to tragedy. All information is imperfect. We have to treat it with humility. Bronowski (1973) The Ascent of Man It seems particularly appropriate to us to begin this book with Jacob Bronowski's passionate message firmly in mind. Those who set out to construct numerical models, especially...