Interest as a political, legal and ethical notion

The article observes the origin of the notion “interest” and main directions of its development in political, legal and philosophy theories of ancient and medieval thinkers, which made a long way of evolution and gave birth to various interpretations and concepts. The author pays special attention to ideas of Plato, Aristotle, Claude Andria Helvetia and Niccolo Machiavelli and others, on the role of interests of an individual, society and state in a fair state structure. The conducted analysis shows that interests, which have a biosocial and neuropsychological nature, are characterized by moral and psychological, esthetic, biological, political, economic, legal and other aspects from the point of view of their substantive side. Interest is not always a willed imperative, but in separate cases, it manifests itself in the form of the driving force for an individual as well as the whole state, and reflects diversification of forms and types of social interaction in the trine “individual-society-state”.