The article presents the brief version of one of the chapters of an unpublished book by V.B. Iordansky (1929 - 2010), who was a prominent specialist in the sphere of scientific research of international relations. What is nationalism? Is it a deviation in social development, or is it a “necessary evil”, inseparable from the existence of any single people? What is the role, what is the meaning of peoples’ traditions and customs for national self-consciousness in modern world? In search for answers to these questions the author considers the problem from the culturological and from the psychological points of view.