On the title page of one of his most renowned works, an eminent historian has placed the following quotation from William Blake : ‘To generalize is to be an idiot. To particularize is the alone distinction of merit.’ Even among contemporary historians, this general attitude towards historical research does not seem to be uncommon. Consequently, since we are about to present an abstract, theoretical model of the open field system, an apology or justification for the approach might be thought in order, for a great many toes will perhaps feel sorely stepped on. However, none will be given, nor is one really necessary. For what is to be understood by ‘generalizing’ or ‘particularizing’ is, of course, a matter of point of reference. What the historian had in mind when selecting the quotation from Blake as a motto was quite probably that, in historical research, general models are easy to come by, but exact explanations for the many variations of history are difficult to achieve. That may be the historian's way of looking at the problem, but it is not necessarily that of the economist. Unless, he would say, there is a theoretical model sufficiently precise as to explain, in a consistent manner, the general phenomenon, various accounts for particular events have not been shown to be relevant, for there is no common theme that has been understood so that the empirical ‘particularization’ can be justified.