mechanics but also special and general relativity, were also criticized on grounds of "idealism". Soviet physicists, such as K. V. Nikolskij and D. Blokhintzev, developed a version of the statistical interpretation of quantum mechanics, which was seen as more adhering to the principles of dialectical materialism. However, although initially planned, this process did not go as far as defining an "ideologically correct" version of physics and purging those scientists who refused to conform to it, because this was recognized as potentially too harmful to the Soviet nuclear program. As Krylov writes on the perils of ideological intrusion into science, "Stalin rolled back the planned campaign against physics and instructed Beria to give physicists some space; this led to significant advances and accomplishments by Soviet scientists in several domains. However, neither Stalin nor the subsequent Soviet leaders were able to let go of the controls completely. Government control over science turned out to be a grand failure, and the attempt to patch the widening gap between the West and the East by espionage did not help. Today Russia is hopelessly behind the West in both technology and quality of life." Sociology After the Russian Revolution, sociology was gradually "politicized, Bolshevisized and eventually, Stalinized". From 1930s to 1950s, the discipline virtually ceased to exist in the Soviet Union. Even in the era where it was allowed to be practiced, and not replaced by Marxist philosophy, it was always dominated by Marxist thought; hence sociology in the Soviet Union and the entire Eastern Bloc represented, to a significant extent, only one branch of sociology: Marxist sociology. With the death of Joseph Stalin and the 20th Party Congress in 1956, restrictions on sociological research were somewhat eased, and finally, after the 23rd Party Congress in 1966, sociology in Soviet Union was once again officially recognized as an acceptable branch of science. Statistics The quality (accuracy and reliability) of data published in the Soviet Union and used in historical research is another issue raised by various Sovietologists. The Marxist theoreticians of the Party considered statistics as a social science; hence many applications of statistical mathematics were curtailed, particularly during the Stalin era. Under central planning, nothing could occur by accident. The law of large numbers and the idea of random deviation were decreed as "false theories". Statistical journals and university departments were closed; world-renowned statisticians like Andrey Kolmogorov and Eugen Slutsky abandoned statistical research. As