Pope Pius XII

"Let no Christian therefore, whether philosopher or theologian, embrace eagerly and lightly whatever novelty happens to be thought up from day to day, but rather let him weigh it with painstaking care and a balanced judgment, lest he lose or corrupt the truth he already has, with grave danger to his faith." --Encyclical Humani Generis ("Concerning Some False Opinions Threatening to Undermine the Foundations of Catholic Doctrine"), 30.