Much of science has in the past ultimately been concerned with trying to find ways to describe natural Systems in terms of numbers. [...]The purpose of this chapter, [...], is to investigate a ränge of Systems that are based on numbers, and to see how their behavior compares with what we have found in other kinds of Systems.

In traditional mathematics, the details of how performed on numbers affect sequences of digits are usually considered quite irrelevant. But what we will find in this chapter is that precisely by looking at such details, we will be able to see more clearly how complexity develops in Systems based on numbers.

And I suspect that in fact the cun it predominance of partial differential equations is in many respects a historical accident - and that had Computer ter.hnnlogy been developed earlier in the history of mathematics, the Situation would probably now be very different.