“All ideologies tend to become reified. Handed down from generation to generation, they end up having a constraining authoritarian form, from which thought can no more free itself. Abstract ideas, principles and concepts are transformed into essences and or forces that are real though invisible and that are obeyed by humans as though they were superior beings.... It is understandable that Medieval Church denounced nominalism .... Its hostility to critical positivism is based on the very same motivation.”

— Paul Szende, Verhüllung und Enthüllung. Der Kampf der Ideologien in der Geschichte (Leipzig: Hirschfeld, 1922), p. 19ff; quoted in Joseph Gabel, Mannheim and Hungarian Marxism, translated by William M. Stein and James McCrate (New Brunswick, NJ: Transaction Publishers, 1991), p. 19.