FOREGROUND AND BACKGROUND

English common law is based on precedent. The results of any court case establish a principle that must be followed in the future. In theory the legal system should become increasingly rigid, but that is not what happens. Rather than considering themselves bound by previous rulings, judges institute subtle changes to the law. They do so by arguing that the details of particular cases are different from one another, so that what once appeared to be a point of general application actually applies in very specific circumstances (Figs. 5.1 and 5.2).

Prehistorians have taken a similar approach to the Three Age Model. This was devised in the nineteenth century when archaeologists believed that progress was based on technological innovation, so that stone gave way to bronze and bronze to iron. Since that time they have retained the terminology but have changed its connotations. These period divisions are not used in a consistent way. The Neolithic, for instance, is defined by its material culture but also by its economy and systems of belief. Recent work has tended to play down the distinction between that phase and the beginning of the Bronze Age. There are other problems as well. In this book two of the chapters begin halfway through the periods into which the sequence was organised. This procedure reflects the timing of fundamental changes in the prehistoric landscape.