ABSTRACT
The peculiarity of the international system in relation to other types of systems is that it has both of the following attributes: it is non-hierarchic and its units are mutually non-mobile. Systemic explanation of unit behaviour may be relevant also in the international system in special regards or during special conditions. Kenneth Waitz' systemic balance of power theory of international politics is superseded by Stephen Walt's balance of threat theory: the latter can, inter alia, account for the prediction shortcomings of the former. Politicians' use of 'security' should be seen as political language with other purposes than analytical ones. The conception of language and reality as existing independently from each other also implies that theoretical concepts can be defined by the analyst; as distinct from concept essentialism, there is no such thing as the 'real' meaning of a concept. The reality of specific theoretical constructs is easily overshadowed by emotions of a more general nature.
