Everything Must Justify Its Existence Before

This line comes from Socialism: Utopian and Scientific (1880), a pamphlet Engels distilled from three chapters of Anti-Dühring at the request of Paul Lafargue. It encapsulates the Enlightenment rationalism that Engels and Karl Marx inherited — the demand that every institution, doctrine, and social arrangement justify itself before the bar of reason rather than appeal to tradition or divine authority. The pamphlet became one of the most widely read socialist texts of the 19th century, translated into more than twenty languages, and served as a primary introduction to Marxist thought for millions of readers.