p The modelling of objects and processes is becoming increasingly widespread in contemporary science. Objects and processes even of the most different kind are, in some respects, similar. For example, a geographical map and the terrain which it depicts are similar, and so is a photograph and the original.

p Due to the similarity of various objects it is possible to model, i. e., to reproduce an object (system) with the help of another object which resembles it in some respects. The method of cognition which with the help of one system (natural and, more often than not, artificial or man-made) makes it possible to reproduce another, more complicated system that is the object of study is called scientific modelling, and the system which reproduces this object is called its model. Modelling is a simplified reproduction of the original, but this simplification should not be arbitrary and excessive, otherwise the model will not resemble the original, and no fresh knowledge about the original will be obtained.

p There are two basic classes of models. Material models are material reproductions of objects which are being studied. Such, for example, are electronic models of the nervous system, the heart, kidneys and other organs and tissues of the living organism that are now used in biology and medicine. Ideal models are a totality of reasoning elements—mathematical and other formulas, equations, logical symbols, diverse signs, and so forth. An important place in the class of ideal models is occupied by mathematical models. The similarity of certain qualitative features in various objects makes it possible to investigate them with the help of the contemporary mathematics, particularly mathematical logic, the theory of probabilities, theory of sets and others, and also electronic computers.

p A model is an effective means of scientific cognition. It 179 comes to the assistance of the researcher when the object being investigated cannot be studied directly, because it is too big, too massive or too far away; because it has excessively high or low temperatures and pressures, and toxic or other properties harmful to man; because its direct study may violate its function and even destroy it, and so forth.

p Another merit of modelling is that with its help it is possible to study objects which do not exist as yet, or which are to be created. First a model is made and then, after it undergoes theoretical and experimental tests, the object itself is made on its basis. For instance, the development of new machines, mechanisms, aircraft, buildings, etc., usually pass through the modelling stage.

p Models are used fairly extensively in physics, chemistry, cybernetics and biology, and are gradually making their way into social sciences, particularly economics. They help to improve the organisation and management of the economy and certain social processes. Already today mathematical models are successfully used in solving certain economic problems, for example, the optimum distribution of machine loading, rationalisation of transportation, analysis of requirements with the view to improving the supply of commodities to the population, and others.

HISTORICAL MATERIALISM