Indifferentism is the belief held by some that no one religion or philosophy is superior to another.
Religious indifferentism is to be distinguished from political indifferentism. Political indifferentism relates to the policy of a State that treats all the religions within its borders as being on an equal footing before the law of the country. Indifferentism is not to be confounded with religious indifference. Indifferentism is primarily a theory disparaging the value of religions; religious indifference designates the conduct of those who, whether they do or do not believe in the necessity and utility of religion, do in fact neglect to fulfill its duties.
Source: Wikipedia
2. Man may, in the observance of any religion whatever, find the way of eternal salvation, and arrive at eternal salvation. (Papal Encyclical, Qui Pluribus, 9 November 1846).
3. Moreover, it is false that the civil liberty of every form of worship, and the full power, given to all, of overtly and publicly manifesting any opinions whatsoever and thoughts, conduce more easily to corrupt the morals and minds of the people, and to propagate the pest of indifferentism. (Papal Allocution, Nunquam Fore, 15 December 1856).