The article formulates and substantiates the philosophical epistemological principle, which generalizes the principle of complementarity of Bohr to all phenomena of reality. The general complementarity principle is formulated as follows: the rational side of reality and its cognition and its associated irrational side of reality and its cognition are complementary to each other. The general principle of complementarity allows one to search for phenomena of duality in various fields, grouping them according to rational and irrational signs.
The article is devoted to the problem of scientific and philosophical status of complementarity principlef. The author analyzes its explication by N. Bohr and its comprehension by scientists and epistemologists. It is shown that generally, the complementarity principle is a set of ideas, which allows comprehending of specific situation in quantum mechanics. Some of ideas – the role of language of classical physics, the role of macro-instrument, the integrity of scientific experiment, the integrity of micro-object – could be seen as general scientific and epistemological principles. The prohibition of ontologisation of quantum phenomenon, which necessarily leads to contradictions is considered as the semantic core of Bohr’s approach. However, the attempts of its generalization in science and philosophy were not successful. The complementarity postulate is viewed as methodological principle of foundations of quantum mechanics in its Copenhagen interpretation.