What encyclical upheld God's sovereignty over the regularity of natural laws?

What encyclical upheld God's sovereignty over the regularity of science?

I believe the encyclical you are looking for is the Encyclical Letter Fides et Ratio on the Relationship between Faith and Reason, by Pope John Paul II.

Fides et ratio is a Papal Encyclical that Pope John Paul II Promulgated on the 14th of September 1998, "On the Relationship between Faith and Reason". In the encyclical, Pope John Paul II addressed the relationship between faith and reason, the first to do so since Pope Leo XIII in 1879, with his encyclical Aeterni Patris. Pope John Paul II described the relationship between faith and reason as 'two wings on which the human spirit rises to the contemplation of truth'.

'This is why I make this strong and insistent appeal—not, I trust, untimely—that faith and philosophy recover the profound unity which allows them to stand in harmony with their nature without compromising their mutual autonomy. The parrhesia of faith must be matched by the boldness of reason.'

In his 1998 encyclical, Pope John Paul II gave an example to the faithful of how to defend faith, without shunning reason. Following and supporting the long tradition of Christian Theology and Philosophy. The Catholic Church has always purported a thesis of harmony between Science and Religion, despite the growing trend of conflict being purported between the two. Through Fides et ratio Pope John Paul II reinforced the Church's stance upon the relationship between Science and The Catholic Church. 'The Church remains profoundly convinced that faith and reason “mutually support each other”; each influences the other, as they offer to each other a purifying critique and a stimulus to pursue the search for deeper understanding.'

'Similarly, fundamental theology should demonstrate the profound compatibility that exists between faith and its need to find expression by way of human reason fully free to give its assent. Faith will thus be able “to show fully the path to reason in a sincere search for the truth. Although faith, a gift of God, is not based on reason, it can certainly not dispense with it. At the same time, it becomes apparent that reason needs to be reinforced by faith, to discover horizons it cannot reach on its own”.'

The relationship between science and the Catholic Church is a widely debated subject. Historically, the Catholic Church has often been a patron of sciences. It has been prolific in the foundation and funding of schools, universities, and hospitals, and many clergy have been active in the sciences. Historians of science such as Pierre Duhem credit medieval Catholic mathematicians and philosophers such as John Buridan, Nicole Oresme, and Roger Bacon as the founders of modern science.1 Duhem found "the mechanics and physics, of which modern times are justifiably proud, to proceed by an uninterrupted series of scarcely perceptible improvements from doctrines professed in the heart of the medieval schools."2 Yet, the conflict thesis and other critiques emphasize the historical or contemporary conflict between the Catholic Church and science, citing, in particular, the trial of Galileo as evidence. For its part, the Catholic Church teaches that science and the Christian faith are complementary, as can be seen from the Catechism of the Catholic Church which states in regards to faith and science:

Though faith is above reason, there can never be any real discrepancy between faith and reason. Since the same God who reveals mysteries and infuses faith has bestowed the light of reason on the human mind, God cannot deny himself, nor can truth ever contradict truth. ... Consequently, methodical research in all branches of knowledge provided it is carried out in a truly scientific manner and does not override moral laws, can never conflict with the faith, because the things of the world and the things of faith derive from the same God. The humble and persevering investigator of the secrets of nature is being led, as it were, by the hand of God despite himself, for it is God, the conserver of all things, who made them what they are.

Catholic scientists, both religious and lay, have led scientific discovery in many fields. From ancient times, Christian emphasis on practical charity gave rise to the development of systematic nursing and hospitals and the Church remains the single largest private provider of medical care and research facilities in the world. Following the Fall of Rome, monasteries and convents remained bastions of scholarship in Western Europe and clergymen were the leading scholars of the age – studying nature, mathematics, and the motion of the stars (largely for religious purposes). During the Middle Ages, the Church founded Europe's first universities, producing scholars like Robert Grosseteste, Albert the Great, Roger Bacon, and Thomas Aquinas, who helped establish the scientific method.

John Paul II on the relationship between the natural sciences and religious belief: five key discourses

From the very beginning of the papacy of John Paul II there has been a reinvigorating view on the relationship between the natural sciences and religious belief. This essay will attempt to explore the veracity of that claim.

Although the views of John Paul II on the relationship of science and faith may be derived from many of his messages, I propose five of his messages as the principal ones in this regard: 1.) the discourse given to the Pontifical Academy of Sciences on 10 November 1979 to commemorate the centenary of the birth of Albert Einstein; 2.) the discourse given on 28 October 1986 on the occasion of the fiftieth anniversary of the Pontifical Academy of Sciences; 3.) the message addressed to the Director of the Vatican Observatory, written on the occasion of the tricentennial of Newton's Principia Mathematica and published as in introduction to the proceedings of the meeting sponsored in 1988 by the Vatican Observatory to commemorate that same tricentennial; 4.) his message on Evolution addressed to the Plenary Session of the Pontifical Academy of Sciences on 22 October 1996; 5.) the encyclical Fides et Ratio, published on 14 September 1998. For the English texts here used see the references below.

The view among many scholars: scientists, philosophers and historians of science, Church historians, etc., of the first two discourses has emphasized the statements made by the Pope concerning the Copernican-Ptolemaic controversy of the 17th century and especially the role of Galileo in those controversies. These statements of the Pope certainly set the stage for a new openness of the Church to the world of science. But they must not be seen myopically but rather against the background of the constant and unflagging efforts of the Pope throughout his papacy to establish a climate of dialogue of the Church with all aspects of modern culture. His role in the drafting of the pastoral constitution of the Second Vatican Council, Gaudium et Spes, well studied by historians of the Council, bears convincing testimony to this. The pastoral concerns of John Paul II dominate his desire to see that the Church is engaged with the modern world and, therefore, with the sciences which constitute an ever increasing role in the definition of modern culture. This is best explored, to my mind, by an investigation of the last three of the five Papal messages listed above. For purposes of an orderly discourse I prefer to postpone the treatment of message (3) until after the treatment of messages (4) and (5).

The message of John Paul II to the Pontifical Academy of Sciences on evolution (4) is characteristic of his openness to dialogue with the sciences. While the encyclical of Pope Pius XII in 1950, Humani Generis, considered the doctrine of evolution a serious hypothesis, worthy of investigation and in-depth study equal to that of the opposing hypothesis, John Paul II states in his message: “Today almost half a century after the publication of the encyclical [Humani Generis], new knowledge has led to the recognition that the theory of evolution is no longer a mere hypothesis” ((4), No. 4, paragraph 2; the English translation of this sentence in Origins is incorrect; the French original is: “nouvelles connaissances conduisent à reconnaître dans la théorie de l'évolution plus qu'une hypothèse”). The sentences which follow this statement indicate that the "new knowledge" which the Pope refers to is for the most part scientific knowledge. He had, in fact, just stated that "the exegete and the theologian must keep informed about the results achieved by the natural sciences". The context in which the message occurs strongly supports this. As the specific theme for its plenary session the Pontifical Academy of Sciences had chosen: The Origin and Evolution of Life, and it had assembled some of the most active researchers in the life sciences to discuss topics which ranged from detailed molecular chemistry to sweeping analyses of life in the context of the evolving universe. Only months before the plenary session of the Academy the renowned journal, Science, published a research paper announcing the discovery that in the past there may have existed primitive life forms on the planet Mars. Furthermore within the previous two years a number of publications had appeared announcing the discovery of extra-solar planets. This ferment in scientific research not only made the plenary session theme very timely, but it also set the concrete scene for the Papal message.

The discussion progresses in the following way: The Church holds certain revealed truths concerning the human person. Science has discovered certain facts about the origins of the human person. Any theory based upon those facts which contradicts revealed truths cannot be correct. Note the antecedent and primary role given to revealed truths in this dialogue; and yet note the struggle to remain open to a correct theory based upon the scientific facts. The dialogue proceeds, in anguish as it were, between these two poles. In the traditional manner of Papal statements the main content of the teaching of previous Popes on the matter at hand is reevaluated. And so the teaching of Pius XII in Humani Generis that, if the human body takes its origins from pre-existent living matter, the spiritual soul is immediately created by God. And so, is the dialogue resolved by embracing evolutionism as to the body and creationism as to the soul? Note that the word "soul" does not reappear in the remainder of the dialogue. Rather the message moves to speak of "spirit" and "the spiritual.”

If we consider the revealed, religious truth about the human being, then we have an "ontological leap", an "ontological discontinuity" in the evolutionary chain at the emergence of the human being. Is this not irreconcilable, wonders the Pope, with the continuity in the evolutionary chain seen by science? An attempt to resolve this critical issue is given by stating that: “The moment of transition to the spiritual cannot be the object of this kind of [scientific] observation, which nevertheless can discover at the experimental level a series of very valuable signs indicating what is specific to the human being” ((4), No. 6, paragraph 2). The suggestion is being made, it appears, that the "ontological discontinuity" may be explained by an epistemological discontinuity. Is this adequate or must the dialogue continue? Is a creationist, interventionist theory required to explain the origins of the spiritual dimension of the human being? Are we forced by revealed, religious truth to accept a dualistic view of the origins of the human person, evolutionist with respect to the material dimension, creationist and interventionist with respect to the spiritual dimension? The message, I believe, when it speaks in the last paragraphs about the God of life, gives strong indications that the dialogue is still open with respect to these questions.

The principal thrust of John Paul II’s encyclical Ratio et Fides [(5), which in the twilight of his papacy summarizes his thinking on the relationship of faith and reason, is a plea that we not lose the search for ultimate truth. He writes, for instance: “She [the Church] sees in philosophy the way to come to know fundamental truths about human life. ... I wish to reflect upon this special activity of human reason. I judge it necessary to do so because at the present time in particular the search for ultimate truth seems often to be neglected” ((5), No. 5)

In this search there are various ways of knowing and among them he contrasts philosophy with the natural sciences: “It may help, then, to turn briefly to the different modes of truth. Most of them depend upon immediate evidence or are confirmed by experimentation. This is the mode of truth proper to everyday life and to scientific research. At another level we find philosophical truth, attained by means of the speculative powers of the human intellect” ((5), No. 30). It is clear that philosophy and the natural sciences must each have their autonomy: “St. Albert the Great and St. Thomas were the first to recognize the autonomy which philosophy and the sciences needed if they were to perform well in their respective fields of research” ((5), No. 45).

The encyclical, while its principal focus is not upon the natural sciences, makes a serious attempt to lay the foundations for dialogue. Scientific research, especially in our day, cannot be excluded from the search for ultimate meaning. Today scientists, within their own well determined methodology, are asking such questions as: why is there anything rather than nothing?; is the universe finite or infinite in time and in space?, is the universe fine-tuned to the existence of intelligent life?; did humans come to be through necessary processes, chance processes, or some combination of the two in a universe fecund to allow both processes together to fructify?

The newness in what John Paul II has said about the relationship between science and religion consists in his having taken a position compellingly different than the one he had inherited. This statement is justified in all of the documents referred to, but principally in the third, the message on the occasion of the tricentennial of Newton's Principia Mathematica (3). John Paul II clearly states that science cannot be used in a simplistic way as a rational basis for religious belief, nor can it be judged to be by its nature atheistic, opposed to belief in God. Rather, he says: “Christianity possesses the source of its justification within itself and does not expect science to constitute its primary apologetic. Science must bear witness to its own worth. While each can and should support the other as distinct dimensions of a common human culture, neither ought to assume that it forms a necessary premise for the other. The unprecedented opportunity we have today is for a common interactive relationship in which each discipline retains its integrity and yet is radically open to the discoveries and insights of the other” ([(3), p. M9). He furthermore states: “Science develops best when its concepts and conclusions are integrated into the broader human culture and its concerns for ultimate meaning and value” ((3), p. M13). Nothing could be further from many of the past reactions of the Church, for instance to the anticlericalism of the 17th and 18th centuries, than the following words of John Paul II: “By encouraging openness between the Church and the scientific communities, we are not envisioning a disciplinary unity between theology and science like that which exists within a given scientific field or within theology proper. As dialogue and common searching continue, there will be growth towards mutual understanding and gradual uncovering of common concerns which will provide the basis for further research and discussion” ((3), p. M7).

The newest element in the new view from Rome is the expressed uncertainty as to where the dialogue between science and faith will lead. Whereas the awakening of the Church to modern science in the 20th century led sometimes to a too facile appropriation of scientific results to bolster religious beliefs, Pope John II expresses the extreme caution of the Church in defining its partnership in the dialogue: “Exactly what form that (the dialogue) will take must be left to the future” ((3), p. M7).

This is clearly the newest and most important posture that the modern Church has taken in its approach to science. It is radically new and in complete contrast with previous history. It is diametrically opposed to accusations of atheism, to a posture of antagonism; it is awakened but expectant.

In his message on the occasion of the tercentenary of Newton’s Principia the Pope raises the question: "Can science also benefit from this interchange?" ((3), p. M7). It takes a great deal of courage and openness to ask that question and it does not have a very clear answer. In fact, it is very difficult to see what the benefits to science as such, that is as a specific way of knowing, might be. In the Papal message it is intimated that the dialogue will help scientists to appreciate that scientific discoveries cannot be a substitute for knowledge of the truly ultimate. In what way, however, do scientific discoveries participate, together with philosophy and theology, in the quest for that ultimate? This is a serious and open question. Obviously, the new view of the interaction between science and religious belief does not have all the answers, but it is an invitation to a common quest.

Fides et Ratio has this to say about St. Thomas’ teaching:

The enduring originality of the thought of Saint Thomas Aquinas

43. A quite special place in this long development belongs to Saint Thomas, not only because of what he taught but also because of the dialogue which he undertook with the Arab and Jewish thought of his time. In an age when Christian thinkers were rediscovering the treasures of ancient philosophy, and more particularly of Aristotle, Thomas had the great merit of giving pride of place to the harmony which exists between faith and reason. Both the light of reason and the light of faith come from God, he argued; hence there can be no contradiction between them.

More radically, Thomas recognized that nature, philosophy's proper concern, could contribute to the understanding of divine Revelation. Faith therefore has no fear of reason, but seeks it out and has trust in it. Just as grace builds on nature and brings it to fulfilment, so faith builds upon and perfects reason. Illumined by faith, reason is set free from the fragility and limitations deriving from the disobedience of sin and finds the strength required to rise to the knowledge of the Triune God. Although he made much of the supernatural character of faith, the Angelic Doctor did not overlook the importance of its reasonableness; indeed he was able to plumb the depths and explain the meaning of this reasonableness. Faith is in a sense an “exercise of thought”; and human reason is neither annulled nor debased in assenting to the contents of faith, which are in any case attained by way of free and informed choice.

This is why the Church has been justified in consistently proposing Saint Thomas as a master of thought and a model of the right way to do theology. In this connection, I would recall what my Predecessor, the Servant of God Paul VI, wrote on the occasion of the seventh centenary of the death of the Angelic Doctor: “Without doubt, Thomas possessed supremely the courage of the truth, a freedom of spirit in confronting new problems, the intellectual honesty of those who allow Christianity to be contaminated neither by secular philosophy nor by a prejudiced rejection of it. He passed therefore into the history of Christian thought as a pioneer of the new path of philosophy and universal culture. The key point and almost the kernel of the solution which, with all the brilliance of his prophetic intuition, he gave to the new encounter of faith and reason was a reconciliation between the secularity of the world and the radicality of the Gospel, thus avoiding the unnatural tendency to negate the world and its values while at the same time keeping faith with the supreme and inexorable demands of the supernatural order”.

Pope John Paul II’s words in his Conclusion are very revealing:

Finally, I cannot fail to address a word to scientists, whose research offers an ever greater knowledge of the universe as a whole and of the incredibly rich array of its component parts, animate and inanimate, with their complex atomic and molecular structures. So far has science come, especially in this century, that its achievements never cease to amaze us. In expressing my admiration and in offering encouragement to these brave pioneers of scientific research, to whom humanity owes so much of its current development, I would urge them to continue their efforts without ever abandoning the sapiential horizon within which scientific and technological achievements are wedded to the philosophical and ethical values which are the distinctive and indelible mark of the human person. Scientists are well aware that “the search for truth, even when it concerns a finite reality of the world or of man, is never-ending, but always points beyond to something higher than the immediate object of study, to the questions which give access to Mystery”.

Pope Pius IX, First Vatican Council, dogmatic constitution Dei Filius on faith & reason, canons on God the Creator of all things:

Canon 5. If any one confess not that the world, and all things which are contained in it, both spiritual and material, have been, in their whole substance, produced by God out of nothing; or shall say that God created, not by his will, free from all necessity, but by a necessity equal to the necessity whereby he loves himself [e.g., a logical necessity]; or shall deny that the world was made for the glory of God: let him be anathema.

Cf. also Pope St. Pius X, Pascendi Dominici Gregis ¶¶16-17.

Addressing your specific questions:

Yes, St. Thomas Aquinas's philosophy and theology has great authority in the Catholic Church, as testified by numerous popes; his Summa Theologica was even placed on the altar, alongside the Bible, at the Council of Trent!

The notion of a physical law is explained very well in ch. 10 "Physical Laws" of The Physical System of St. Thomas (1893) by G. M. Cornoldi, S.J.

The Catholic physicist Pierre Duhem (1861-1916) describes modern physics's narrower conception of "physical law" in Aim & Structure of Physical Theory (La théorie physique: Son objet, sa structure 1906) pt. 2, ch. 4.
_{On how more modern philosophers of science conceive physical laws, cf. Aristotle's Revenge (2018), §3.3 "How the laws of nature lie (or at least engage in mental reservation)" by Thomist philosopher Ed Feser.}

Neither definition turns the laws of physics into logical necessities. God is free to create however He chooses (as long as it does not imply a contradiction); cf. Summa Contra Gentiles II ch. 23 "That God does not act by natural necessity".

Ancient Greek philosophers didn't distinguish theology from natural philosophy, thinking that the universe was an extension of God (pantheism). This led to believing that the universe (and its laws) could only be one way. Catholics believe that God and the universe are distinct, so theology (the study of God) and natural philosophy (the study of the physical world) are distinct disciplines, too; this freed ancient thought from its closed-minded dogmatism, enabling science to progress and not be "stillborn" (as physicist and theologian Stanley L. Jaki, O.S.B. calls pre-Christian-era science in Savior of Science).

See also Fr. Jaki's Miracles & Physics and St. Thomas's Summa Contra Gentiles, lib. 3 cap. 101 on the three types of miracles, miracles being "works that are sometimes done by God outside the usual order assigned to things".