In the years after the 1905–1907 revolution, Social Democrats operated in the political shadows and turned much of their energy to internal differences of strategy and philosophy. Lenin took the issues of Marxist philosophical orthodoxy on questions of materialist ontology so seriously that he was willing to break off his relationship with one of his most talented comrades, Bogdanov, and create a schism in the diminished Bolshevik ranks. Stalin, then a minor figure in the party leadership, was a moderate in this debate and pushed for reconciliation and unity in the Bolshevik faction.
