 Schönflies (1906) stuck to a contentual, genetic conception of sets. According to him, sets are generated and, once formed, are conceptually invariant. When a new set is built up, it is added to those that have been used in forming it, without altering their pre-existent structure. So self-membership does not make sense, the universal set does not exist and Russell’s paradox disappears. His view can be seen as hinting at a sort of iterative conception of sets. For Schönflies, the contradictions arise in logic, as opposed to mathematics, and are due to the scholastic nature of logic. He regarded logic as having an unhealthy influence (“unheilvollen Einflüss”) on mathematics (“Für den Cantorismus, aber gegen den Russellismus” is the final motto of Schönflies 1911).