Alessandro Giostra






            Jaki’s conception on the science-faith interaction is founded upon a correct definition of those two disciplines as the only way out to avoid misunderstandings. The quantitative nature of the scientific discourse, in which measurements play a key role, rejects any possibility of an unresolvable conflict with faith, whose salvific aim doesn’t involve quantities. Many errors have been committed in the past by some intellectuals who failed to define the respective boundaries of science and faith. Therefore, concordism and the pretension of using science to demonstrate the fallacy of faith are clear methodological mistakes.

            In the history of Western thought Galileo Galilei (1564-1642) is often considered the symbol of the opposition between science and scientific rationality, as many authors paid attention to Galilei’s condemnation in order to highlight a sort of science-faith incompatibility. According to Jaki, Galilei’s case just represents a misunderstanding about the actual contents of those two disciplines. The father of modern science offers Jaki a starting point to highlight various aspects of science, faith and their own relationship. Galilei’s figure is present in all Jaki’s works. More in detail, in 2001 Jaki published a booklet on that issue[1] and he also dedicated a chapter to Galilei in a following work[2].


            Some legends concerning Galilei

            Galilei’s greatness as a scientist is unquestionable, although his own merits have been exaggerated by someone who ignored that he could not demnostrate the terrestrial motion. Moreover, his personal vicissitudes have given some historians of science the opportunity to invent some legends. One of them consists in a marble plaque, in the entrance of the Tower of Pisa, carrying the following inscription:


“By means of experiments on the fall of heavy bodies performed from the top of this Tower, Galileo Galilei established the laws on motion and founded thereby the science of mechanics, anticipating many discoveries of his own and of future learned man”[3].


The origin of that legend forms part of the Racconto Istorico della Vita del Sig.r Galileo Galilei issued by Galilei’s biographer Vincenzo Viviani (1622-1703). In his work Viviani highlights Galilei’s studies on the free falling bodies as follows:


“the velocity of moving bodies of the same material, of unequal weight, moving through the same medium, did not mutually preserve the proportion of their weight as taught by Aristotle, but all moved at the same speed; demonstrating this with repeated experiments from the height of the Campanile of Pisa in the presence of the other teachers and philosophers, and the whole assembly of students”[4].


To tell the truth, that plaque was placed there in occasion of a scientists’ gathering in Pisa in 1883. Moreover, the Latin language renders that inscription a kind of official declaration, able to convince visitors of being in a place where a crucial physical experiment was performed. The misleading character of Viviani’s claim has been easily detached. Unfortunately, the Galileo case is full of legends; it is part, indeed, of an erroneous history of science, founded upon prejudicial doctrines. As a matter of fact, many historians still ignore the investigations carried on by Pierre Duhem (1861-1916), the French scientist and philosopher who discovered the medieval origin of modern science.

The failure to recognize the Christian origin of science is due to a mistaken consideration of science. It would be enough to pay attention to the basic tenets of the Scientific Revolution in order to realize the truth. The process which led to the quantitative description of phenomena and defeated finalistic and pantheistic worldviews did not emerge out of nothing in the XVI-XVII Centuries. It started in the late Scholastic age, when Christian natural philosophers achieved the early quantitative theories of the motion of bodies; their researches were connected with the will to make the Christian theology stronger. Unfortunately many historians are still influenced by legends and deny that evidence:


“The notion that this idea began in the Middle Ages, which so many love to consider the Dark Ages, surely would not please that modern mind that has been conditioned to viewing the relation of science and religion as an incessant warfare between the two. To such minds it is something most unsettling to consider that science may be a chip from the old block, the block being nothing else than medieval Christianity”[5].


Furthermore, the protagonists of the Scientific Revolution believed in a real universe created out of nothing by God and ruled by the same mathematical laws. Except Newton, indeed, whose religious belief consisted in a sort of Unitarianism, “all those in question believed in a saving Birth that once took place in a manger”[6].

            According to another famous legend, Galilei was able to offer a consistent demonstration of the terrestrial motion and his condemnation can be deemed to be a proof of the Church closeness to the scientific rationality. Notwithstanding his achievements, the father of modern science came to a superficial conclusion when he considered the phenomenon of tides as a clear proof of the Copernican theory. His own discoveries through the telescope, announced in March 1610 in the Starry Messenger, were able only to stress the errors of the Ptolemaic cosmology. The rolling of the Medicean Stars around Jupiter clearly showed that the Earth is not the only center of gravitation within the universe, “but it was another thing to assure absolute physical truth on behalf of heliocentrism”[7]. His argument of tides, expressed in the fourth day of the Dialogue on the Two Chief Systems, and the theory of comets stated in the Assayer, represent two grievous mistakes in a very successful scientific career[8]. In opposition to his own experimental method, he aprioristically trusted in the planetary circular paths; thus, he “remained, however, a prisoner of the Aristotelian dichotomy between celestial and terrestrial motions by ascribing a necessarily circular motion to all celestial bodies”[9]. Although his investigations were essential for the rise of modern science, he couldn’t own the basic elements concerning the motion of bodies to overcome the problems due to the terrestrial movement. Because of those problems, indeed, many astronomers had rejected the Copernican theory:


“Galileo, whose telescope surely demolished the Aristotelian world view, failed to provide the theory of motion which the heliocentric system demanded. Galileo was no Newton”[10].


Therefore, while Galileo charged the academics for their rejection of the new astronomy, he was anchored to the past too. As a consequence, he did not take into consideration other solutions:


“Galileo himself could have stolen perhaps the march on Newton, had his jealousy of Kepler not made him slight and ignore the latter’s three laws of planetary motion, all indispensable for Newton”[11].


According to Jaki, the absolute belief in the mathematical language of nature led Galilei to make scientific and theological mistakes, though this fact may appear a heresy to his admirers. Among the most famous passages of Galilei’s works we can find the one forming part of the Dialogue on the Two Chief Systems, in which Galilei distinguishes the extensive knowledge, which is proper of God, from the intensive understanding which is typical of man[12]. In his words Galilei establishes the divine nature of human mathematical understanding, whose necessity had been already declared in the Assayer. The human intensive learning, although inferior to God’s as regards to its dimension and velocity, can be deemed to be absolute as the divine one. Galilei’s vision confirms some basic tenets of the Christian theology, namely the existence of man as the apex of creation and his being made in the image of the Creator. In Jaki’s mind, however, Galilei’s statement highlights his own ‘hubris’ and just the idea of the perfect human knowledge is the reason why Galilei founded his erroneous demonstration of the Copernican Theory only upon the mathematical formalism:


Galileo thought in the Dialogue that man's notion of quantities is as perfect as that of God. So spoke a Platonist, unmindful of his hubris. No wonder that Galileo took the mathematical formalism of the heliocen­tric system for an absolutely demonstrative proof”[13].


Even the affirmation that only the mathematical features of nature deserve to be considered, clearly shows the will to praise his own worldview:


Galileo argued in his Assayer (1623) that only primary qualities were real, whereas secondary qualities (taste, color etc) were mere conventions. He surely did not take the flavor of a glass of Frascati for a mere convention. He hardly took the splendid hues of the Florentine landscape outside his villa in Arcetri for mere subjectivity. He was not the last great scientist to be flagrantly inconsistent”[14] […]The answer he gave, the sharing of all bodies in the moving earth's impetus, was in the right direction, but it was not until Newton that the success of mathematical physics, based on the first law of motion, the law of inertial motion, made those problems appear if not meaning­less at least irrelevant for the purposes of science. None of this could yet be seen clearly by Galileo. Galileo was, however, fully seized with the prospect that he might become the first to prove the physical truth of the Coperni­can system”[15].


            Science and faith

            The failure in finding a valid demonstration of the Copernican astronomy represents the basic point of Galileo’s unfortunate events and the main question pertaining to the science-faith relationship in his vicissitudes. A common error can be detected in the thought of those characters who participated in the Galileo case, namely the fact that they didn’t recognize that ‘impassable divide’[16] between the respective dominions of science and religion. Some factors influenced the Church behavior against Galilei and Jaki laid stress on that situation:


Further, could the Church easily yield to Galileo's championing of Heliocentrism and not provide further fuel to the Protestant charge that Rome was inattentive to the Bible? The Church could have argued, of course, that Luther achieved the dubious distinction of having called Coperni­cus a fool, which the Church never did”[17].


Thus, notwithstanding the impossibility for Galileo to prove the terrestrial motion, the Church committed the epistemological mistake of trusting in concordism. He was right in saying that the Bible is not a scientific book, as the salvific aim of the Christian message does not involve the laws of motion and quantities. Galilei, however, exhibited his own belief in a certain sort of concordism in the final words of his Letter to the Grand Duchess Christina. In that text, indeed, he did not abandon the idea of the absence of scientific contents in the Bible. In any case, he declared that the Copernican Theory, if carefully considered, could agree with some meaning of the Scriptures:


“As for other passages of Scripture which appear to contradict the Copernican position, I have no doubt that, if this position were once known to be true and proven, those same theologians who now, believing it to be false, find such passages incapable of being interpreted in a way compatible with it, would find interpretations for them which would accord with it very well, especially if their understanding of Holy Scripture were combined with some knowledge of astronomy”[18].


Galilei not only believed in Copernicus’ theory of planetary motion, as he accepted the Copernican view as a whole: astronomy is a mathematical discipline and the literal interpretation of those biblical passages describing the motion of the sun cannot be accepted:


“But if perchance there are certain ‘idle talkers’ who take it upon themselves to pronounce judgment, although wholly ignorant of mathematics, and if by shamelessly distorting the sense of some passage in Holy Writ to suit their purpose, they dare to reprehend and to attack my work; they worry me so little that I shall even scorn their judgments as foolhardy […]  mathematics is written for mathematicians; and among them, if I am not mistaken, my labours will be seen to contribute something to the ecclesiastical commonwealth”[19]. 


Galilei’s vision on the specific mathematical language of science led him to “pointing at the scientific ignorance of some of his theological critics”[20]. Most of the prelates who charged Galilei were not learned astronomers; however, that situation did not imply that the Church as a whole was unable to express a well-founded opinion on that delicate matter. The famous letter by Cardinal Robert Bellarmine (1542-1621) to Paolo Antonio Foscarini (1565-1616) can be deemed to be a document containing the position of both Copernicans and supporters of the traditional cosmology[21]. St. Robert Bellarmine was an exegete and consultor of the Holy Office. Moreover, during his youth he had been teacher of mathematical disciplines in some Jesuit colleges. At the moment of writing that letter, Bellarmine had already left the scientific studies. In any case, he still kept a deep knowledge of astronomy which rendered him able to understand the advantages and disadvantages of the new theory. His awareness was surely enough to realize the lack of a true demonstration of the terrestrial motion. Bellarmine affirmed that if he saw a valid proof of the theory, he would be willing to admit that he did not understand the seemingly contrary biblical texts, but that he was not convinced by Galilei’s arguments. The holes in Galileo’s formulation, indeed, were also apparent to his contemporaries. That is the reason why we can agree with Jaki’s argument upholding Galilei “was unjust in claiming that his judges were devoid of competence”[22].

            In the long history of the Church, some episodes helped in spreading false legends. A typical kind of those science fiction accounts concerns the so called ‘martyrs of science’. In addition to Galilei, Giordano Bruno (1548-1600) is still praised by the Church enemies as a martyr of scientific truth. Actually, Bruno cannot be considered a martyr as he abjured his own theories in order to keep his life. Moreover, he was not a scientist and founded his worldview upon a universal animism which is totally different from the arrangement of modern science. His cosmological works include some errors, and in The Ash Wednesday Supper he rejected the idea of the mathematical understanding of the universe, namely the basic point of the protagonists of modern science, as in his mind only the occult disciplines can reveal the secrets of the world:


But for all that he did not move too much beyond them; being more intent on the study of mathematics than of nature he was not able to go deep enough and penetrate beyond the point of removing from the way the stumps of inconvenient and vain principles, so as to resolve completely the difficult objections, and to free both himself and others from so many vain investigations, and to set attention firmly on things constant and certain[23].


Therefore, it is easy to understand why Galilei is considered a martyr too, above all for being a real scientist, while Bruno was not. Galilei himself contributed to spreading such a belief, because his “complaint was typical of one who, though not plagued with a martyr complex, consid­ered himself a martyr without seeing that he was largely responsible for bringing martyrdom upon himself”[24].



            Jaki considers Galilei an emblematic figure, as his personal events can be deemed to be a synthesis of the main errors due to an erroneous approach to the science-faith relationship.


Let it be recalled that the conflict then was about two philoso­phies. One was riveted in the uniquely great facts of salvation history (of which none was greater than the Babe born in the manger), facts that did not mean to give rules about the quantita­tive appraisal of the facts of the physical world. The other was riveted in assigning much more to quanti­ties than they could ever contain, however much they conveyed”[25].


As regards to the Galileo case, he upholds a position that, although it could seem paradoxical, just comes to the point. Galilei committed a scientific error, even if, from a theological point of view, his position was stronger than Bellarmine’s:


The Galileo-case, if carefully considered, should be a harder pill for them to swallow than it is for the Church. Of little comfort should it seem to them in that classic clash between science and Christian religion, Galileo proved to be a better theologian than Bellarmine and others, whereas the latter had the better of a strictly scientific point: they rightly insisted that Galileo in vain claimed that he had provided an experimental proof of the rotation and orbiting of the earth. It was clear that in doing so he contradicted some of his own statements. Within half a year of the publication of the Dialogue it was shown in print that in presenting the tides as such a proof Galileo merely confused two reference systems, one centered on the earth, the other on the sun. The earth still moved, but not because of the words, "Eppur si muove," which Galileo never uttered. He was not made of the fabric that makes mar­tyrs, whether for science, or preferably for Christ[26].


In another recent issue Jaki expressed the same idea with the following words:


“The reason was the failure of Galileo and his ecclesiastical judges to see and ponder in its enormous weight the difference between numbers and all other words. Had this been done by Galileo he would have given a different twist to his concern to save the Church from ignoring Copernicus. His ecclesiastical judges might also have perceived what was really wrong with Aristotle’s science”.


The same kind of mistake is made by those students who believe that the condemnation of the heliocentric theory shows the fallacy of the papal infallibility:


Then it was the fortune of the Church that the scientific proof of a given (helio­centric) arrangement of the physical world was very incomplete even if one considers that scientific proofs can never be absolut­ely complete. It was still a fortune for the Church that it was not Paul V but a Cardinal, Bellarmine, who handed down the judgment against heliocen­trism. The difference meant that papal infallibility escaped by the skin of its teeth, so to speak, from its being compromised”[27].


The Galileo case has been useful to the Church in order to avoid committing the same error again. It should be, however, a warning to those scientists who ignore the difference between the specific contents of science and and ethics. The ethical dimension cannot be confused with the truth of a scientific law, and it should constantly monitor the effects of scientific applications:


the Vatican can come into conflict with science only by making a declaration about the arrangement of bodies, either of molecules or of galaxies. This is most unlikely to happen in view of the lesson of the Galileo case. Another Galileo case, a very un-Galilean, is in the making because too many scientists claim that what is feasible and useful is necessarily ethical. They therefore clamor for the freedom of scientific research unfettered by old-fashioned ethical norms”[28].




[1] S.L. Jaki, Galileo Lessons, Real View Books, Kinfolk 2001.


[2] Jaki, Questions on Science and Religion, Real View Books, Kinfolk Court 2004, pp. 93-108..


[4] “le velocità de' mobili dell'istessa materia, disegualmente gravi, movendosi per un istesso mezzo, non conservano altrimenti la proporzione delle gravità loro, assegnatagli da Aristotele, anzi che si muovon tutti con pari velocità, dimostrando ciò con replicate esperienze, fatte dall'altezza del Campanile di Pisa con l'intervento delli altri lettori e filosofi e di tutta la scolaresca”. Galileo Galilei, Opere, Edizione Nazionale a cura di Antonio Favaro, Giunti Barbera, Firenze 1890-1909,vol. XIX, p. 606.


[5] Jaki, Questions on Science and Religion, Real View Books, Pinckney 2004, p. 187.

[6] Jaki, The Savior of Science, cit., p. 54.


[7] Jaki, Galileo Lessons, cit., p. 11.


[8] The best exposition of Galilei’s theory on tides can be found in: W.R. Shea, Galileo's Intellectual Revolution, New York and Macmillan, London 1972.

[9] Jaki, Cosmos and Creator, Scottish Academic Press, Edinburgh 1980, p. 30.


[10] Jaki, The Mirage of Conflict between Science and Religion, Real View Books, New Hope 2009, p. 1.

[11] Ibidem, p. 49.

[12] G. Galilei, Selected Writings, new translations by William R. Shea and Mark Davie, Oxford University Press, Oxford 2012, pp. 228-230.

[13] Jaki, Galileo Lessons, cit., p. 26.

[14] Ibidem, p. 26.


[15] Jaki, Ibidem, p. 10.

[16] That subject is typical of Jaki’s works and it is mainly expressed in The impassable divide or the separation between science and religion, Real View Books 2008.

[17] Jaki, Galileo Lessons, cit., 21.


[18] Galilei, Selected Writings, cit., p. 93.

[19] N. Copernicus, On the Revolutions of the Heavenly Spheres, translated by C.G. Wallis, in Great Books of the Western World, Britannica Great Books, Vol. 16, Chicago 1952, p. 507.

[20] Jaki, Galileo Lessons, cit., p. 13.

[21] Galilei, Opere, cit., vol. XI, pp. 171-172.


[22] Jaki, Galileo Lessons, cit., p. 17.


[23] G. Bruno, The Ash Wednesday Supper, translated by S.L. Jaki, First Dialogue, available at

[24] Jaki, Galileo Lessons, cit., p. 17.

[25] Ibidem, p. 29.

[26] Jaki, Christ and Science, Real View Books, Royal Oak 2000, pp. 24-25.

[27] Jaki, Galileo Lessons, cit., p. 27.

[28] Ibidem, p. 31.