Summary — Two recent projects for a pluralism of ecclesial membership. For Eastern Catholics: simultaneous membership to the Catholic and Orthodox Churches through the recognition of the authority of the Bishop of Rome, and the obedience to the Orthodox Patriarch rather than to the Catholic Patriarch. For Western Non-Catholics: simultaneous membership to the Catholic Church through the participation in the Eucharist, and to the Christian Community of origin retaining its respective confessional differences. Both projects are to be considered impracticable for dogmatic reasons. Indiscriminate hospitality and indefinite confessional status (« qualunquismo »). Negative repercussions on the ecumenical movement.