Hughes Felicité Robert de Lamennais  

The Index Librorum Prohibitorum ("List of Prohibited Books") is a list of publications which the Catholic Church censored for being a danger to itself and the faith of its members. Almost every modern Western philosopher was, or is, included on the list — even those that believed in God, such as Descartes, Kant, Berkeley, Malebranche, Lamennais and Gioberti. That some atheists, such as Schopenhauer and Nietzsche, are not included is due to the general (Tridentine) rule that heretical works (i.e., works that contradict Catholic dogma) are ipso facto forbidden. Some important works are absent simply because nobody bothered to denounce them.