The article substantiates the concept of duality in European romanticism, which was associated with the philosophy of the universal universe with its fundamental universal polarity of material and spiritual principles. Russian romanticism took up the baton of European romanticism and actively developed the concept of universal duality. Based on the fiction texts of V. Zhukovsky, K. Batyushkov, and E. Baratynsky, the thesis is proved that the author's intention was to comprehend a series of plot intricacies and paradoxes that were revealed in the structure of a double plot. The external plot outline was a bifurcation and division of all possible images of doubles, while the internal subtext contained the idea of internal unity. Based on the narrative cycle of A. Pogorelsky, the principles of Russian Romanticism's commitment to the concept of duality are revealed based on the fact that it uses the motif of a machine gun, the technique of mirroring, and a fantastic game with the number "two" and its possible meanings. As a result, it is concluded that European and Russian romanticism considered one of the most important authorial tasks to be research and deep immersion in the nature and mental organization of the human personality, which is in a situation of psychological duality.