The Galileo Affair: At the Crossroads of Religion and Science

Editor’s note: The following article is an excerpt from Pope John Paul’s recent speech to the Pontifical Academy of Sciences. It addresses the controversial, and much-misunderstood, Galileo condemnation, which is now officially void.

A twofold question is at the heart of the debate of which Galileo was the center. The first is of the epistemological order and concerns biblical hermeneutics. In this regard, two points must again be raised. In the first place, like most of his adversaries, Galileo made no distinction between the scientific approach to natural phenomena and a reflection on nature of the philosophical order, which that approach generally calls for. That is why he rejected the suggestion made to him to present the Copernican system as a hypothesis, inasmuch as it had not been confirmed by irrefutable proof. Such, therefore, was an exigency of the experimental method of which he was the inspired founder.

Second, the geocentric representation of the world was commonly admitted in the culture of the time as fully agreeing with the teaching of the Bible, of which certain expressions, taken literally, seemed to affirm geocentrism. The problem posed by theologians of that age was, therefore, that of the compatibility between heliocentrism and Scripture.

Thus the new science, with its methods and the freedom of research that they implied, obliged theologians to examine their own criteria of scriptural interpretation. Most of them did not know how to do so.

Paradoxically, Galileo, a sincere believer, showed himself to be more perceptive in this regard than the theologians who opposed him. “If Scripture cannot err,” he wrote to Benedetto Castelli, “certain of its interpreters and commentators can and do so in many ways.” We also know of his letter to Christine de Lorraine (1615), which is like a short treatise on biblical hermeneutics.

From this we can now draw our first conclusion. The birth of a new way of approaching the study of natural phenomena demands a clarification on the part of all disciplines of knowledge. It obliges them to define more clearly their own field, their approach, their methods, as well as the precise import of their conclusions. In other words, this new way requires each discipline to become more rigorously aware of its own nature.

The upset caused by the Copernican system thus demanded epistemological reflection on the biblical sciences, an effort which would later produce abundant fruit in modern exegetical works and which has found sanction and a new stimulus in the dogmatic constitution Dei Verbum of the Second Vatican Council.

The crisis that I have just recalled is not the only factor to have had repercussions on biblical interpretation. Here we are concerned with the second aspect of the problem, its pastoral dimension.

By virtue of her own mission, the Church has the duty to be attentive to the pastoral consequences of her teaching. Before all else, let it be clear that this teaching must correspond to the truth. But it is a question of knowing how to judge a new scientific datum when it seems to contradict the truths of faith. The pastoral judgment that the Copernican theory required was difficult to make, insofar as geocentrism seemed to be a part of scriptural teaching itself. It would have been necessary all at once to overcome habits of thought and to devise a way of teaching capable of enlightening the people of God. Let us say, in a general way, that the pastor ought to show a genuine boldness, avoiding the double trap of a hesitant attitude and of hasty judgment, both of which can cause considerable harm.

Another crisis, similar to the one we are speaking of, can be mentioned here. In the last century and at the beginning of our own, advances in the historical sciences made it possible to acquire a new understanding of the Bible and of the biblical world. The rationalist context in which these data were most often presented seemed to make them dangerous to the Christian faith. Certain people, in their concern to defend the faith, thought it necessary to reject firmly based historical conclusions. That was a hasty and unhappy decision.

It is necessary to repeat here what I said above. It is a duty for theologians to keep themselves regularly informed of scientific advances in order to examine, if such be necessary, whether or not there are reasons for taking them into account in their reflection or for introducing changes in their teaching.

If, contemporary culture is marked by a tendency to scientism, the cultural horizon of Galileo’s age was uniform and carried the imprint of a particular philosophical formation. This unitary character of culture, which in itself is positive and desirable even in our own day, was one of the reasons for Galileo’s condemnation. The majority of theologians did not recognize the formal distinction between Sacred Scripture and its interpretation, and this led them unduly to transpose into the realm of the doctrine of the faith a question that in fact pertained to scientific investigation.

In fact, as Cardinal Poupard has recalled, Robert Bellarmine, who had seen what was truly at stake in the debate, personally felt that, in the face of possible scientific proofs that the Earth orbited round the sun, one should “interpret with great circumspection” every biblical passage that seems to affirm that the Earth is immobile and “say that we do not understand, rather than affirm that what has been demonstrated is false.” Before Bellarmine, this same wisdom and same respect for the divine word guided St. Augustine when he wrote,

If it happens that the authority of Sacred Scripture is set in opposition to clear and certain reasoning, this must mean that the person who [interprets Scripture] does not understand it correctly. It is not the meaning of Scripture that is opposed to the truth, but the meaning that he has wanted to give to it. That which is opposed to Scripture is not what is in Scripture, but what he has placed there himself, believing that this is what Scripture meant.

A century ago, Pope Leo XIII echoed this advice in his encyclical Providentissimus Deus: “Truth cannot contradict truth, and we may be sure that some mistake has been made either in the interpretation of the sacred words or in the polemical discussion itself.”

Cardinal Poupard has also reminded us that the sentence of 1633 was not irreformable and that the debate, which had not ceased to evolve thereafter, was closed in 1820 with the imprimatur given to the work of Canon Settele.

From the beginning of the Age of Enlightenment down to our own day, the Galileo case has been a sort of “myth,” in which the image fabricated out of the events was quite far removed from reality. In this perspective, the Galileo case was the symbol of the Church’s supposed rejection of scientific progress or of “dogmatic” obscurantism opposed to the free search for truth. This myth has played a considerable cultural role. It has helped to anchor a number of scientists of good faith in the idea that there was an incompatibility between the spirit of science and its rules of research on the one hand, and the Christian faith on the other. A tragic mutual incomprehension has been interpreted as the reflection of a fundamental opposition between science and faith. The clarifications furnished by recent historical studies enable us to state that this sad misunderstanding now belongs to the past.

From the Galileo affair we can learn a lesson that remains valid in relation to similar situations that occur today and that may occur in the future.

In Galileo’s time, to depict the world as lacking an absolute physical reference point was, so to speak, inconceivable. And since the cosmos as it was then known was contained within the solar system alone, this reference point could only be situated in the Earth or in the sun. Today, after Einstein and within the perspective of contemporary cosmology, neither of these two reference points has the importance they once had. This observation, it goes without saying, is not directed against the validity of Galileo’s position in the debate; it is only meant to show that often beyond two partial and contrasting perceptions there exists a wider perception that includes them and goes beyond both of them.

Another lesson that we can draw is that the different branches of knowledge call for different methods. Thanks to his intuition as a brilliant physicist and by relying on different arguments, Galileo, who practically invented the experimental method, understood why only the sun could function as the center of the world as it was then known, that is to say, as a planetary system. The error of the theologians of the time when they maintained the centrality of the Earth was to think that our understanding of the physical world’s structure was in some way imposed by the literal sense of Sacred Scripture.

In fact, the Bible does not concern itself with the details of the physical world, the understanding of which is the competence of human experience and reasoning. There exist two realms of knowledge, one that has its source in revelation and one that reason can discover by its own power. To the latter belong especially the experimental sciences and philosophy. The distinction between the two realms of knowledge ought not to be understood as opposition. The two realms are not altogether foreign to each other; they have points of contact. The methodologies proper to each make it possible to bring out different aspects of reality.


Blessed John Paul II was the 264th Pope.

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