Some notes on systems models and modelling

This paper discusses the basic concepts of models and modelling. The difference in information contents between a model and the real or imagined situation it is intended to represent is pointed out, and the fact that a model should not be divorced from its intended purpose is strongly emphasized. The act of modelling is defined and discussed. It is concluded that even though formalized approaches to modelling (such as the systems approach) exists ; modelling, as well as the use of models, remains very much an art rather than a science.