“The difficulty in the way of giving an answer is a profound one. Ultimately it is due to the fact that there is no appropriate category in Catholic thought for the phenomenon of Protestantism today (one could say the same of the relationship to the separated churches of the East). It is obvious that the old category of ‘heresy’ is no longer of any value. Heresy, for Scripture and the early Church, includes the idea of a personal decision against the unity of the Church, and heresy’s characteristic is pertinacia, the obstinacy of him who persists in his own private way. This, however, cannot be regarded as an appropriate description of the spiritual situation of the Protestant Christian. In the course of a now centuries-old history, Protestantism has made an important contribution to the realization of Christian faith, fulfilling a positive function in the development of the Christian message and, above all, often giving rise to a sincere and profound faith in the individual non-Catholic Christian, whose separation from the Catholic affirmation has nothing to do with the pertinacia characteristic of heresy. Perhaps we may here invert a saying of St. Augustine’s: that an old schism becomes a heresy. The very passage of time alters the character of a division, so that an old division is something essentially different from a new one. Something that was once rightly condemned as heresy cannot later simply become true, but it can gradually develop its own positive ecclesial nature, with which the individual is presented as his church and in which he lives as a believer, not as a heretic. This organization of one group, however, ultimately has an effect on the whole. The conclusion is inescapable, then: Protestantism today is something different from heresy in the traditional sense, a phenomenon whose true theological place has not yet been determined."
