Pope Pius X
Pascendi Dominici Gregis §15
Pascendi Dominici Gregis: On the Doctrines of the Modernists
15 But this doctrine of experience is also under another aspect entirely contrary to Catholic truth. It is extended and applied to tradition , as hitherto understood by the Church, and destroys it. By the Modernists, tradition is understood as a communication to others, through preaching by means of the intellectual formula, of an original experience . To this formula, in addition to its representative value, they attribute a species of suggestive efficacy which acts both in the person who believes, to stimulate the religious sentiment should it happen to have grown sluggish and to renew the experience once acquired, and in those who do not yet believe, to awake for the first time the religious sentiment in them and to produce the experience . In this way is religious experience propagated among the peoples; and not merely among contemporaries by preaching, but among future generations both by books and by oral transmission from one to another. Sometimes this communication of religious experience takes root and thrives, at other times it withers at once and dies. For the Modernists, to live is a proof of truth, since for them life and truth are one and the same thing. Hence again it is given to us to infer that all existing religions are equally true, for otherwise they would not live.
Source: Pascendi Dominici Gregis (Vatican.va)