Galileo: 350 years later * (1)

Author: Mariano Artigas
Published in: Nuestro Tiempo, nº 343 (January-February 1983), pp. 70-77.
Publication date: January-February 1983 (Updated and illustrated: January 2006)

In 1543 Copernicus died, the Polish canon whose ideas were to have a powerful influence on the systematic birth of modern science. * (2) The same year saw the publication of his On the Revolutions of the Celestial Orbits, in which he set out the extensive mathematical reasoning behind the calculation of the orbits of the planets around the sun * (3) The book began with a foreword by the Protestant theologian Andreas Osiander, warning that Copernicus' heliocentrism - the claim that the sun is at the centre of the world and the earth moves around it - was only a useful mathematical hypothesis, not a statement of reality. The foreword was not actually signed by Osiander, so it gave the impression that it was by Copernicus himself.

Galileo * (4) began to support heliocentrism around 1610 when, having just invented the telescope, he observed phenomena - such as the phases of Venus - that were best explained by this doctrine. * (5) If he had held it as a simple hypothesis, in the style of Osiander, nothing would have happened. But he asserted it as true, and that was the accusation that led to his prosecution.

Paradoxically, today it is often said that all scientific knowledge is conjectural, that is, that scientific theories are mere hypotheses that are subject to experimental test , but that can never be considered as true. What has happened in these 350 years?

The process

Indeed, 350 years ago, on 23 September 1632, Pope Urban VIII ordered Galileo to appear before the Roman Inquisition. In February, the Dialogue on the Two Chief Systems of the World had been published, a work in which Galileo put the arguments for and against heliocentrism into the mouths of three fictitious characters (two deceased friends of Galileo and an ancient philosopher), giving a clear advantage to those in favour. * (6) Galileo could be accused of breaking his word, since in 1616 he had promised Cardinal Bellarmine not to uphold the heliocentric doctrine. Galileo claimed not to have defended it, but it seemed clear that he was not telling the whole truth. He was condemned to ecclesiastical censure and imprisonment. Since he was willing to accept the view held by the court, the censures were pardoned and the imprisonment was commuted to confinement in his villa at Gioiello, where he continued his scientific work until 1642, when he died at the age of 78. * (7)

The trial began on 12 April 1633, and the sentence was read out on 22 June. The heliocentric hypothesis was not discussed, oddly enough. That topic was taken as settled. In fact, the Holy official document had order in 1616 its opinion to a commission of theologians, who replied that to say "that the Sun is at the centre of the world and immobile without local motion is an absurd and false proposition in Philosophy and formally heretical, since it is expressly contrary to the Sacred Scripture", and to say "that the Earth is neither at the centre of the world nor immobile is also an absurd and false proposition in Philosophy and, theologically considered, is at least erroneous in faith". This opinion was never officially published as an act of the Magisterium of the Church. But it served to make Galileo commit himself in 1616 not to defend heliocentrism, and was the basis for the trial of 1633.

The arguments

It is easy to understand, from a philosophical point of view, the motives that led those theologians to their opinion of 1616. It is enough to imagine what one can think about the topic if one uses the data of ordinary experience. To imagine it, one must think of what one knows for oneself, forgetting that one has learned since childhood that the earth revolves around the sun. This was the status of those theologians, and modern astronomy was taking its hesitant first steps: Galileo also had no convincing arguments in favour of the heliocentric hypothesis. For reasoning under those conditions, the new doctrine could seem "absurd and false at Philosophy". However, this did not give the Church cause for concern, as long as the truths of the Christian faith were not affected.

As far as faith is concerned, the reasons of the theologians are included in the opinion. There is an apparent contradiction between the new doctrine and Sacred Scripture. Unfortunately, the theologians were not up to the task on this point. And it was not a difficult question, since the whole tradition of the Church showed that, without detracting from the truth of the Bible, there are facts which are narrated in the language proper to ordinary experience, since God does not intend to reveal to men truths proper to natural science. This subject of interpretation is already found in the most ancient Holy Fathers. As if this were not enough, Galileo himself had clearly and faultlessly recalled how there was no difficulty in interpreting correctly the passages of Scripture which speak of the motion of the Sun and the stillness of the Earth; he had done so in a letter addressed to his disciple Benedetto Castelli, and more extensively in another long letter addressed to Christina, mother of the Grand Duke of Tuscany. It seems clear that various environmental and personal circumstances must have caused him to forget some simple theological principles that would have avoided the process and any other difficulties.

And the story continues

Galileo's trial by no means meant the stagnation of the new science. Shortly afterwards, Newton firmly established the instructions of modern physics. Galileo himself published in 1638, after the trial, one of his major works: Discourses and Demonstrations Concerning Two New Sciences. * (8) The main party harmed by the trial was the Church: even today it is still used by some to unjustly portray the Church as the enemy of progress, with reasoning that has little or nothing to do with historical and theological reality.

However, there is one aspect of the Galileo process that is not only topical, but of increasing interest. It is the question of the nature of scientific truth. This was the topic chosen for the annual Symposium of the International Academy of Sciences Philosophy held in Brussels in 1981, where it became clear - once again - that this is a complex (more so than it might have seemed to Galileo and his judges) and ideologically loaded topic . Galileo helped to set in motion a powerful machine, modern experimental science, without fully understanding how it works; after three centuries and several decades, we understand the machine better and have perfected it considerably, but its mysteries have not disappeared.

Cardinal Bellarmine asked Galileo to limit himself to speaking as if heliocentrism were only a hypothesis useful for scientific calculations. * (9) The successive progress of science later gave rise to scientistic doctrines, according to which science not only reached the truth, but was the only way to reach it. In the 18th and 19th centuries, the rise of scientism led materialism, mechanism and positivism to claim to be the true Philosophy, supported by science, and the remedy for social ills.

However, the profound transformations in science in the 20th century brought to light the provisional nature of the edifices that had been considered definitive. For example, relativistic mechanics and quantum mechanics showed that Newtonian mechanics had serious limits and that some of its basic concepts had to be modified. This gave rise to the modern Philosophy of science, one of the main features of which is that it stresses the essentially hypothetical or conjectural character of all scientific theory: there would be no place in science for definitive truths, and even the very concept of "truth" is relegated to being a "regulative idea" that directs the research but is never achieved.

So was Bellarmine right?

Science and truth

The answer is clear: no. Science is more than just a useful tool for mastering reality. The scientific research seeks, first and foremost, to know what reality is like, and often succeeds in doing so.

Current science testifies that, in order to know reality, it is often necessary to make use of very complex abstract theories and experimental instruments that provide data that are difficult to interpret. Science is full of hypotheses and conjectures. This is logical, since it seeks to know aspects of reality that are not immediately evident and often escape our senses. But through highly sophisticated procedures, it is wresting ever deeper secrets from reality.

At the same time, the scientific knowledge is always limited and subject to further progress. But this does not mean that it is always conjectural. For example, we know of the existence of many atomic phenomena and their properties, although many other aspects of the atomic world can only be hypothesised.

In general, the canons of truth are identical in ordinary knowledge and in experimental science: direct evidence from observation, conclusions from correct reasoning, indirect evidence from the reliable testimony of others. The same procedures that are used in everyday life to recognise truth are used in science, and it could not be otherwise: the only difference is that the sciences systematically use theoretical and experimental instruments that often go beyond what is used in the ordinary knowledge .

This explains why there can be no real contradiction between the correct conclusions of the sciences and those of ordinary or philosophical reasoning.

It does not seem to be possible to admit, therefore, that the sciences provide only hypotheses or conjectures more or less corroborated by experience, although this view is current in the current Philosophy of science. Conjecturalism, which considers certainty as unattainable by man, attributes to all science and often to the whole of human knowledge characteristics that only apply to certain aspects of that knowledge.

An intellectual fad

Nevertheless, conjecturalism is fashionable. It has been widely disseminated by Karl Popper and his disciples* (10) and, although the Popperian Philosophy has been subject to numerous criticisms, its basic thesis on the conjectural nature of all human knowledge is implicitly or explicitly accepted by many scientists and philosophers today, and continues to spread through the publications of authors as diverse as the German Gerard Radnitzky or the Frenchman and award Nobel laureate François Jacob.

The spread of conjecturalism can be explained as a reaction to the scientistic dogmatism of the past. Man, including the scientist, has become rather cautious in assessing the conclusions of his reasoning, since much knowledge that was once considered definitive has finally proved to be limited and open to revision. There is also an important ideological component: the quest for certainty seems to go hand in hand with fanaticism and intolerance, the real cause of more than a few social ills. Significantly, one of Popper's major works is entitled The Open Society and its Enemies, and many regard it as a solid basis for social rationality.

Conjecturalism may seem plausible because a part of our knowledge, including the great systems of science, has hypothetical aspects. Such systems are usually constructed according to the hypothetico-deductive method: from basic hypotheses, consequences are drawn whose truth one tries to test, but the truth of these is not sufficient to establish with certainty all the claims of the theory. Einstein's relativity, for example, contains well-proven laws along with postulates and statements whose truth is difficult to establish.

But it is clear that not everything knowledge is conjectural. If it were, we could not even make reasonable conjectures or rely on the most palpable evidence, and science itself would collapse at its base.

Conjecturalism is a simplification that distorts the true value of knowledge. And, if one draws its logical consequences, one ends up with logical contradictions and practical inconsistencies. Although Popper harshly criticises theoretical scepticism and ethical relativism, his thesis leads inexorably to both if developed logically.

Science and faith

Today, it seems that the roles of Galileo and the Church have been reversed. In his addresses to researchers, teachers and students, Pope John Paul II has repeatedly insisted on the need to overcome the scepticism and relativism that condition much of today's culture, and he explains how the Christian faith provides the necessary instructions for this. * (11)

Indeed, divine Revelation confirms certain truths that can be discovered by reason: among them, that the Universe is the work of an infinitely intelligent creator God staff ; that this Universe bears within itself and manifests a rational order, the mark of God's wisdom and power; that man has been created by God in his image and likeness, possessing a spiritual soul whose intelligence is capable of penetrating the natural order and of attaining the truth; that man has a divine mandate to dominate the world, so that the knowledge he attains and the resulting mastery of reality are ordered to serve man in the service of agreement with God's plans.

In an address to university students in Cologne on 15 November 1980 ( speech ), John Paul II denounced the "functionalist" conception of science, according to which the concept of "objective truth" is considered useless or meaningless, and science is reduced to a mere instrument for a technique which, in this perspective, is not subject to higher ethical norms. This functionalism ends up making man a victim of his own products: experience in this respect is, unfortunately, all too abundant.

This doctrine, recalled on several occasions by John Paul II, belongs to the perennial teachings of the Church. In fact, it is the same doctrine that was taught at the time of Galileo. Moreover, it was to a large extent the inspiration that guided Galileo and the great founders of modern science, all of them deeply religious, in their work .

It is interesting to mention in this respect a thesis which the historian of science Stanley Jaki has documented extensively in books and essays. * (12). Jaki argues that experimental science found a viable birth in the "cultural matrix" of Christian Europe, where, after centuries of widespread Christian influence, the aforementioned truths about the rationality of the Universe and the human capacity to penetrate that God-caused order were widely held. This climax was not enough to make science successful, but its lack was enough to make it impossible for many centuries. In fact, several ancient cultures, flourishing in many respects, produced only isolated attempts at the scientific-experimental aspect, and Jaki attributes these successive "abortions" of modern science to the lack of the minimum convictions necessary to realise the scientific research .

The convictions and writings of Kepler, Galileo and Newton - to name but a few of the founders of modern science - support Jaki's judgement. Creative science" has always been the work of scientists committed to the above-mentioned convictions in one way or another: at the very least, they have admitted their consequences for the rational foundations of science. It is possible to jump on the bandwagon of science already underway and even make contributions of some value with a pragmatic attitude, but the creative pages of science, which make possible those that follow, are the work of scientists like Faraday, Maxwell, Planck, Einstein or Heinsenberg who, even if on specific occasions they have supported the rational foundations of science, have been able to make a contribution of some value to it, even if on specific occasions they supported a certain positivism, later clearly expressed philosophical convictions which, without being exclusive to Christianity, in fact, thanks to it, came to shape a whole culture which made the birth and systematic development of modern science possible.

Science and the human being

The Church has deplored the lack of understanding of the legitimate autonomy of science in the trial of Galileo: reference letter is explicitly referred to topic in the Constitution Gaudium et Spes of the Second Vatican Council (no. 36, grade 7). John Paul II, in a speech to the Pontifical Academy of Sciences (15 November 1980), repeated this lamentation, referring also to the suffering caused by the trial of Galileo, and pointing out, moreover, that in this matter there are more numerous and more important coincidences between science and faith.

Indeed, the discrepancies could have been avoided if the doctrine of the Church had been correctly applied, and Galileo himself clearly noted this in writing. The coincidences, partly obscured by the course set by the process, have repercussions whose importance is all the more apparent in the present age, as has been pointed out. The Christian faith, which has deeply animated the birth and the development of modern science, is a solid basis for today's great task of refund man's confidence in his reason.

The reaction to the scientistic rationalism that considered human problems solved by science has been an irrationalism that reduces science to a purely technical instrument, and which favours a sceptical and pragmatic mentality in which the great human values are annihilated or simply ignored. The ideological and social consequences are obvious. The humanism that our age needs must include a correct evaluation of human rationality. It is important to realise that truth exists, that it can be attained, and that, although the human knowledge is limited, we can in many cases reach certainty even if we do not exhaust all the content of the truth possessed. It is also important to understand that ordinary knowledge , experimental science, philosophical reflection and supernatural faith are diverse but harmoniously complementary approaches to the one objective truth.

The Catholic Galileo would perhaps be astonished to see how science is sometimes distorted for the benefit of sceptical or materialistic ideologies that are totally alien to him. Scientific progress, today more than ever, reveals to us a truly prodigious natural order which clearly points to the wisdom and power of the Creator and the uniqueness of the human spirit capable of knowing and mastering this rationally ordered nature: this perspective, which inspired the great scientists who launched modern science, is the basis of a humanism urgently demanded by today's civilisation.

Conjecturalism seems to be a natural ally of a sceptical mentality and a liquidation of objective values, although the intention of those who profess it may be otherwise. Alongside it, there is a proliferation of pseudo-scientific doctrines which, claiming to be based on the methods and results of science, often build castles in the air and spread a conceptual confusion for which almost anything can be true if it coincides with one's own preferences. At a distance of 350 years, the trial of Galileo - with what it may have contained of misunderstandings and polemics already overcome - speaks to us of a commitment to truth whose consequences, both positive and negative, are now perhaps more apparent than then, since the theoretical and practical potentialities of Galileo's science have enormous implications for all orders of human life.