The following is taken from Owen Chadwick’s From Bossuet to Newman.

In July 1601 Father Gaspar Hurtado, of the University of Alcala, defended as thesis for his doctorate a number of propositions: among them, that ‘It is not de fide that a particular person, e.g. Clement VIII, is the successor of St Peter’. The troubles did not ensue until spring 1602, when an informer complained in a series of letters to the Papal Secretary of State, and still more, after 7 March 1602 when a theologian of the Jesuit College at Alcala, Onate, maintained the same thesis in a public act under the presidency of another Jesuit, Luis de Torres. The Jesuits, in a spirit of reverence, carefully refrained from inserting the name of the reigning Pope.

The thesis bears directly upon our problem, the problem of immutability. For it offers a peculiarly interesting question about the nature of the logically implicit and its relation to moral certainty. Is the belief that this man is the Pope simply a particular contained in a universal, as you deduce that this baptism regenerates from the proposition that all baptisms regenerate? If so, you may argue that it is implicitly revealed and therefore de fide. But this is difficult to maintain. For you are not asserting that you believe this Pope to be the successor of St Peter because all popes are the successors of St Peter: that would be a true particular contained in a universal. You are asserting that this individual man is the Pope: and it appears that you cannot secure the proposition without the inquiries of natural reason comparable to those inquiries which are not immediate but inform us after investigation that Cicero was a man. This premise, whatever ‘moral certainty’ might be attached to it, could not claim the immediate certainty which might alone be held to justify the ‘revealed’ inference. The premise depended on the probable, highly probable, fulfilment of a complex series of practical and mental conditions. It was not easy to demonstrate that he who was accepted as Pope had been validly baptized, validly ordained, and canonically elected without simony.

Consequently the Jesuit Fathers did not suppose that they were saying anything startling or original when they presented their public thesis. They did not allow for the atmosphere of theological suspicion and distrust which was then hanging like a mist over Spain. A number of their antagonists accused the Jesuits of doubting whether Clement VIII was Pope. They even supplied a motive for the thesis—the Jesuits believed that the Pope would decide against them upon the doctrine of grace, and were already preparing their future line of retreat. The Jesuits replied, with a becoming firmness, that they had no idea in the world of questioning whether Clement VIII was the Pope. The question was not at all whether this statement was true. The question was whether it was revealed to be true in the original deposit of faith.

The matter was complicated by the opinions of Pope Clement VIII himself. His Papal Secretary of State was that coughing, asthmatic, pock-marked Pietro Aldobrandini of whom Ranke drew so lively a picture. Aldobrandini, a born and effective administrator, appears at first to have been incapable of understanding the theological point, incapable of distinguishing between ‘true’ and ‘revealed to be true’. He was not the only administrator to feel muddled. It is odd, said the Papal Nuncio satirically to the Grand Inquisitor, that after eleven years of pontificate, when even the Turks and the heretics believe Clement VIII to be Pope, there should be doubt only in Spain. Under Aldobrandini’s terrible indictment of the Jesuits, the Spanish Inquisition, obediently but reluctantly, moved into half-hearted action. They imprisoned Ofiate, de Torres and two other Fathers from the College at Alcala, the Rector of the College and the gentle Vasquez himself, one of the most eminent theologians in Spain.

The investigations of the Inquisitors did not run smoothly. None of the theologians whom they consulted would classify the opinion as heretical, even if it were admitted to be scandalous. The Jesuits produced many approved authors who had maintained the doctrine. Better still, they proffered to the papal nuncio the commentary upon St Thomas Aquinas by the Dominican leader Banez, open at the page where Banez had maintained something like the same doctrine. After only a month and a half, on 17 June 1602 the rector of the College and Vasquez were released, and the two others were allowed to return home to a temporary house-arrest.

A little controversy of this sort probably convinces no one. Eminent theologians like Vasquez on the one side or Suarez on the other were unmoved by popular and diplomatic clamour about scandal, they were concerned only with what they conceived to be the nature of revelation. While it is possible that the side of the Alcala theses may not have received as stout a defence as it may have deserved out of a desire to avoid popular misunderstanding, it is certain that both opinions continued to be held. Yet, apart from the incidental excitements, to which all theologians are sometimes liable when misunderstood by their episcopal superiors, there was a real argument about the nature of theological inferences. The papers of the Roman censors show that several theologians thought they perceived an overriding necessity, in a matter so momentous, for an unfailing and absolute certainty. And if this certainty could not (as was at first asserted) be secured by the plea that an inference from one revealed premise and one premise of natural reason was itself revealed, then it must be secured through the infallible authority of the Church which has received this Pope as the Pope.

It may be objected, then, that the Church’s definition is a new piece of revelation. If the Church can make an inference ‘supernaturally certain’ when by natural reason it is not more than ‘morally certain’, then the Church is no longer unfolding the inner content of the revelation, is no longer declaring what is (in the strictest logical sense) implicit. She is bringing into the revelation a statement from outside it. She must be adding to, supplementing, the revelation once given by God. Suarez did not shrink from the necessary consequence. He admitted it boldly. A definition by the Church is ‘equivalent’ to the revelation, is a completion or ‘consummation’ of the revelation. It had the same authority and was to be accepted by the assent of fides divina in the same way. And he admitted, even (contrary to the dominant tradition of thought) that an alleged ‘private revelation’ to a Christian individual could become binding upon all the faithful provided that the Church accepted and approved the private revelation.

The thought of Suarez’s successor and critic, Cardinal John de Lugo, showed still more clearly what was happening. In Suarez the belief that the definition of the Church was compensating for the weakness of an unrevealed premise is necessary to his argument, but it is partially concealed. Lugo displayed the consequence, as the only apparent means of avoiding Suarez’s language about ‘equivalence’ to revelation, new revelation. He knew that all Christian tradition denied the possibility of new revelation to the Church. He held that Suarez was therefore wrong in effectively allowing the possibility of new revelation. God reveals nothing which he has not revealed at least’ in confuso’. Yet Lugo stated the same doctrine as Suarez in other, and tautological, words. God does not reveal new truth: but He does reveal that the Holy Spirit guides the Church to correct definitions. There is therefore new truth: and we know it to be true, not because God reveals it immediately, but because He reveals the instrument of defining it to be inerrant. Instead of one revealed premise and one unrevealed premise, there are now two revealed premises, one of which is the proposition ‘that which the Church defines with the assistance of the Spirit cannot be untrue’. The theory of Lugo is like a courteous bow, a raising of the hat in token of respect to the fair lady Immutability whom he was about to abandon to her fate. He need not have been so reluctant to admit Suarez’s wording.

Both Suarez and Lugo tried to safeguard their opinion from the charge that it was against any sound Vincentian theory of an unchanging tradition. They both continued to assert that the apostles knew explicitly all the doctrines which the Church would later draw from the teaching passed from the apostles to the Church implicitly, that the apostles were explicitly aware of such doctrines as the two wills or transubstantiation. They believed that to no Christian was it possible to assert that the Church now knew more of truth than the apostles had received from their Lord. They both contended that definitions were always concerned with defining the true sense of scripture or drawing out its implications or applying the once-given revelation to particular and new contingencies. But, as a fact, they knew enough history to admit that the Church had sometimes defined, though one premise was of natural reason: and if the definition was to be a proclamation that a doctrine was revealed, this could only be secured if the definition in some way overcame the lurking weakness of the natural premise, and therefore it was necessary to postulate that the definition was ‘equivalent’ to the revelation.

The theory lay open to a grave objection from the point of view of the traditionalists, an objection which Lugo himself raised and faced but did not answer. If this particular theory of definitions is true, historical inquiries are superfluous. It is no longer necessary for the ecclesiastical authorities to inquire into what the scripture says explicitly, or what the ancient Church taught and did. There is no longer need to inquire what is tradition. For any rational theory of tradition, some safeguard must be found to show that scripture and tradition do in due measure control or limit what definitions are possible to the Church. The language of Suarez and Lugo provided no such safeguard. Some of their more conservative contemporaries, facing the same difficulty, argued that the Pope was only infallible in definition when he had made due and diligent inquiry into scripture and tradition. Such a restriction was impossible for Suarez and Lugo upon the principles which they had adopted, and their language, however they might assert the unchanging nature of Christian tradition, could offer no safeguard that the tradition was truly unchanging.