EN
Following Kurt Gödel's incompleteness theorem, it should be observed that Keynesianism cannot be fully explained on economic grounds alone. A justified assessment of validity of any model requires that it should be referenced in a wider context. A natural framework for such assessments is provided by the general system's theory. When logical homologies that link separate bodies of science are identified, it is possible to apply concepts and methodology of a more advanced discipline into the approach of the less advanced one. At least nine logical homologies among Keynesianism and the ideas of contemporary natural sciences have been identified so far. The analysis of the non-linear model of business fluctuations (Keynes - Samuelson - Gabisch) indicates that the degree of complexity of any economy is subject to changes in relation to the contemplated control parameters.