Revisiting the Galileo Affair

Recently, in a talk to a small group of Catholic women scientists, I suggested we need to see events in the 17th century from the perspective of 17^th century history and scientific knowledge.

Indeed, from today’s perspective, it may seem completely antiquated not to know that the Earth is orbiting the Sun, and not vice versa. In the early 17th century, though, there were (at least) 4 models of our planetary system:

• the Ptolemaic system (geocentric),
• the Copernican system (heliocentric),
• the Tychonic system (geo-heliocentric), and
• the Keplerian system (heliocentric, elliptic orbits)

The Galileo affair has indeed often been used as an argument that the Catholic Church was hostile to science and that Galileo was a martyr for science, as it were. This timeline article is intended to set the historical record straight. Based on the scientific knowledge of the time, a heliocentric model was not obvious. While heliocentrism ultimately turned out to be right, Galileo could not present the scientific proofs for it, which came much later. Moreover, Galileo ventured into advising theologians how to interpret Scripture, going beyond his position as a scientist.

A timeline representation of the story is available here (click on the image below:)

Justine Siegemund: a midwife with a scientific mind

Today’s Doodle is dedicated to an amazing woman: Justine Siegemund (1636-1705), a midwife and author who had a truly scientific outlook and was a deeply pious Lutheran Christian. She is best known for her influential textbook on midwifery, “Die Kgl. Preußische und Churfürstl. Brandenburgische Hof-Wehe-Mutter” (The Royal Prussian and Electoral Brandenburg Court Midwife), which was first published in 1690 and went through many editions in the following centuries.

Siegemund began practicing midwifery in the early 1660s and quickly gained a reputation as a skilled and compassionate practitioner. She was appointed as a midwife in the Silesian town of Liegnitz (Legnica) and later became the official midwife to the court of the Elector of Brandenburg, delivering more than 6,000 babies in her lifetime.

Niels Steno, the Father of Stratigraphy

On 11 January 1638, Niels Steno was born. He was a Danish anatomist, palaeontologist and geologist. He was ordained a Catholic bishop in 1677 in Italy and moved to the Lutheran part of Germany and died in 1686. Having established the theoretical basis for stratigraphy, he can be called the Father of Stratigraphy.  

In his work on geology “De solido intra solidum naturaliter contento dissertationis prodromus“ (The Prodromus of Nicolaus Steno’s Dissertation Concerning a Solid Body Enclosed by Process of Nature Within a Solid, 1669) Steno describes four of the defining principles of the science of stratigraphy. These were:

• the law of superposition: New layers of sediment are deposited on top of older layers (law of superposition), one can determine relative time sequence by examining the order in which strata appear – “At the time when a given stratum was being formed, there was beneath it another substance which prevented the further descent of the comminuted matter and so at the time when the lowest stratum was being formed either another solid substance was beneath it, or if some fluid existed there, then it was not only of a different character from the upper fluid, but also heavier than the solid sediment of the upper fluid.”

Christopher Clavius SJ: astronomer, mathematician and educator

Christopher Clavius, S.J.  (25 March 1538 – 06 Feb 1612) was a German Jesuit known for his reform of the calendar, and a mathematician and gifted educator. He joined the recently founded Jesuit order in 1555 and was sent to Coimbra, Portugal, to pursue his studies. On 21 August 1560, he observed a sun eclipse, an event which convinced him to devote his life to mathematical and astronomical study. Following this eclipse observation, he went to Italy later in 1560 and studied theology at the Jesuit Collegio Romano in Rome. He was ordained in 1564. He remained at the Collegio Romano were he began teaching mathematics in the year of his ordination. In fact, except for a period in Naples around 1596 and a visit to Spain in 1597, Clavius was to remain Professor of Mathematics at the Collegio Romano for the rest of his life. He continued with his studies in Theology and became a full member of the Jesuit Order in 1575.

in 1579, he was elected as member by Pope Gregory XIII to the commission to oversee the reform of the calendar. The old Julian Calendar had been established by an edict of Julius Caesar in 45 BC.  Because the system of Julian years and leap years did not correspond exactly to the length of the astronomical year, dates of important Christian feasts had gotten out of alignment with the seasons. This commission adopted the ideas for calendar reform of Aloysius Lillius, with some modifications, and in 1582 Pope Gregory XIII promulgated the new calendar. Catholic countries quickly adopted the “Gregorian calendar,” but Protestant and Eastern Orthodox countries only slowly followed. In 1588, it became his role to explain and defend the calendar reform, and he did so in Novi calendarii romani apologia and subsequent works to counter arguments coming from Protestants, but also from astronomers and mathematicians.

Galileo Galilei was familiar with Clavius’s books, and he visited Clavius during his first trip to Rome in 1587. After that they corresponded from time to time about mathematical problems, and Clavius sent Galileo copies of his books as they appeared. Clavius was and remained a defender of the geocentric system although he was impressed by Galilei’s telescopic discoveries as he wrote in 1611, a year prior to his death.

His true and lasting influence was the adoption of rigorous mathematical curricula in Jesuit colleges, at a time when the importance of mathematics in natural science (then called “natural philosophy”) was widely underappreciated. He wrote widely used textbooks and influenced future generations of astronomers and mathematicians.

Image: Christopher Clavius. Line engraving by E. de Boulonois., Wikimedia

Sources:

Thony Christie, A loser who was really a winner.

Christopher Clavius (1537-1612), The Galileo Project

J J O’Connor and E F Robertson, Christopher Clavius

Stephen M. Barr and Andrew Kassebaum, Important Catholic Scientists of the Past, Christopher Clavius (new on the website of the Society of Catholic Scientists)

Thony Christie, Christopher and the calendar

John Ray: Inexhaustible Glory of the Creator

On 17 January 1705, John Ray (1627–1705) died in Black Notley (Essex, England). He was an English naturalist, sometimes referred to as the father of English natural history. He published important works on botany, zoology, and natural theology. His classification of plants in his Historia Plantarum, was an important step towards modern taxonomy. Ray rejected the system of dichotomous division by which species were classified according to a pre-conceived, either/or type system, and instead classified plants according to similarities and differences that emerged from observation.

He was the first to give a biological definition of the term species:

“… no surer criterion for determining species has occurred to me than the distinguishing features that perpetuate themselves in propagation from seed. Thus, no matter what variations occur in the individuals or the species, if they spring from the seed of one and the same plant, they are accidental variations and not such as to distinguish a species… Animals likewise that differ specifically preserve their distinct species permanently; one species never springs from the seed of another nor vice versa”. (History of Plants 1686)

In his time, Natural Sciences and Natural theology were not yet clearly divided. In 1691, he also wrote the book The Wisdom of God in the Works of Creation. It was a treatise on natural theology based upon his botanical and zoological observations that was destined to exert a profound influence many scientists and theologians of the 18th century. He influenced William Paley who clearly, as we would see it today, overemphasized the idea to see God’s direct intervention in every beautiful creature in this world. William Paley’s theological concept was already challenged in his time by theologians like John Henry Newman.

“The treasures of nature are inexhaustible…If man ought to reflect upon his Creator the glory of all his works, then ought he to take notice of them all and not to think anything unworthy of his cognisance.”

—John Ray, English Naturalist (1627–1705), from The Wisdom of God Manifested in the Works of the Creation (London, GB: Samuel Smith, 1691), 130.

Robert Boyle: Book of Nature & Book of Scripture

Robert Boyle (15 January 1627 – 31 December 1691) was an Anglo-Irish chemist and physicist. Considered one of the founders of modern chemistry, his scientific work was animated by a sincere apologetic vein. In addition to scientific works, he also authored moral and theological works that reveal his knowledge of oriental languages and sacred scripture.

Born in Lismore, Ireland, his researches led him to study in continental Europe where he would meet Galileo Galileo. At the age of 27 or 28, he moved to Oxford, and here, and at Gresham College in London, he and his assistant Robert Hooke constructed an air pump, through which they discerned the scaling relation known as Boyle’s law, P ∝ 1/V.

He believed the study of nature and the attributes of God were the noblest aim of life.

“In ‘The Excellency of Theology, Compared with Natural Philosophy’ (1674, written 1665), he noted, ‘The vastness, beauty, orderliness of heavenly bodies; the excellent structure of animals and plants; and other phenomena of nature justly induce an intelligent, unprejudiced observer to conclude a supreme, powerful, just, and good author.’ Boyle had a lifelong passion to educate and Christianize the native populations of Ireland, America, and the Orient. Accordingly, he subsidized various translations of the New Testament, e.g., Arabic, Turkish, et al. In his will, moreover, he left funds for eight annual lectures in a London parish … The last lecture argued in favor of a Divine Providence from the constitution of the universe as demonstrated in the Principia.” [1]

As he had written:

“ …the two great books, of nature and of scripture, have the same author, so the latter does not hinder at all an inquisitive man’s delight in the study of the former.” [2]

References:
[1] Seeger, Raymond J. “Boyle, Christian Gentleman.” The Journal of the American Scientific Affiliation, 37 (Sept. 1985): 183-184.
[2] Robert Boyle, Thomas Birch “The Works of the Honourable Robert Boyle: In Five Volumes”, 1744, The Excellency of Theology, p. 429

Niels Steno: From Scientist to Bishop

On 25 November 1686, Niels Stensen died in Schwerin, at the age of 48. He was a Danish anatomist, palaeontologist and geologist. The mineral stenonite was named in his honour. He was ordained a Catholic bishop in 1677 in Italy and moved to the Lutheran part of Germany.

In October 1666 two fishermen caught a huge female shark near the town of Livorno, and Ferdinando II de’ Medici, Grand Duke of Tuscany, ordered its head to be sent to Steno. Steno dissected the head and published his findings in 1667. He noted that the shark’s teeth bore a striking resemblance to certain stony objects, found embedded within rock formations, that his learned contemporaries were calling glossopetrae or “tongue stones”. Ancient authorities, such as the Roman author Pliny the Elder, in his Naturalis Historia, had suggested that these stones fell from the sky or from the Moon. Others were of the opinion, also following ancient authors, that fossils naturally grew in the rocks. Steno’s contemporary Athanasius Kircher, for example, attributed fossils to a “lapidifying virtue diffused through the whole body of the geocosm”, considered an inherent characteristic of the earth – an Aristotelian approach. Fabio Colonna, however, had already shown in a convincing way that glossopetrae are shark teeth, in his treatise De glossopetris dissertatio published in 1616. Steno added to Colonna’s theory a discussion on the differences in composition between glossopetrae and living sharks’ teeth, arguing that the chemical composition of fossils could be altered without changing their form, using the contemporary corpuscular theory of matter.

Steno’s work on shark teeth led him to the question of how any solid object could come to be found inside another solid object, such as a rock or a layer of rock. The “solid bodies within solids” that attracted Steno’s interest included not only fossils, as we would define them today, but minerals, crystals, encrustations, veins, and even entire rock layers or strata. He published his geologic studies in “De solido intra solidum naturaliter contento dissertationis prodromus”, or “Preliminary discourse to a dissertation on a solid body naturally contained within a solid” in 1669. Steno was not the first to identify fossils as being from living organisms; his contemporaries Robert Hooke, John Ray, and Leonardo da Vinci also argued that fossils were the remains of once-living organisms.

Graphic: Illustration from Steno’s 1667 paper comparing the teeth of a shark head with a fossil tooth. Sources: http://www.inters.org, wikipedia

Ismaël Bullialdus: Theoretical Inverse-Square Law

On 28 September 1605, Ismaël Bullialdus (1605–1694) was born in Loudun, France.

He was a French Catholic priest (raised in a Calvinist family/ ordained a Catholic priest at 26 years old), who worked as a mathematician and physicist, and who is today most remembered as the so-called “finder, not the keeper, of the inverse-square law.”

As noted in the book Gravitation and Cosmology (Wiley & Sons, 1972) by Dr. Steven Weinberg, 1979 Nobel Laureate in Physics, professor at University of Texas at Austin.

“The first suggestion of an inverse-square law may have been made around 1640 by Ismaël Bullialdus (1605–1694). However, it was certainly Newton who in 1665 or 1666 first deduced the inverse-square law from observations.”

Original text:

“Virtus autem illa, qua Sol prehendit seu harpagat planetas, corporalis quae ipsi pro manibus est, lineis rectis in omnem mundi amplitudinem emissa quasi species solis cum illius corpore rotatur: cum ergo sit corporalis imminuitur, & extenuatur in maiori spatio & intervallo, ratio autem huius imminutionis eadem est, ac luminus, in ratione nempe dupla intervallorum, sed eversa.”

Translated at MacTutor History Archives:

“As for the power by which the Sun seizes or holds the planets, and which, being corporeal, functions in the manner of hands, it is emitted in straight lines throughout the whole extent of the world, and like the species of the Sun, it turns with the body of the Sun; now, seeing that it is corporeal, it becomes weaker and attenuated at a greater distance or interval, and the ratio of its decrease in strength is the same as in the case of light, namely, the duplicate proportion, but inversely, of the distances [that is, 1/d²].”

Referenced:
—Weinberg, Steven. Gravitation and Cosmology: Principles and Applications of the General Theory of Relativity. (Hoboken, NJ: John Wiley & Sons., 1972), 13.
—Bullialdus, Ismaël. Astronomia Philolaica. (1645), Bk I, Ch. XII.
— O’Connor, John J. and Roberson, Edmund F. “Ismael Boulliau,” The MacTutor History of Mathematics Archive.

Marin Mersenne: Communication is Key

On 1 September 1648, Marin Mersenne (1588-1648) died in Paris. A French philosopher, physicist, and ordained priest, he acted as a liason between a number of the scientists and thinkers of his time, such as Fermat, Gassendi, and Pascal. He defended Descartes and Galileo against criticism from theologians and fought against pseudo-sciences such as astrology and alchemy. Mersenne is also remembered today thanks to his association with the Mersenne primes. The Mersenne twister, named for him, is frequently used in computer engineering, and in related fields such as cryptography. However, Mersenne was not primarily a mathematician; he wrote about music theory and other subjects. He edited works of Euclid, Apollonius, Archimedes, and other Greek mathematicians. But perhaps his most important contribution to the advance of learning was his extensive correspondence (in Latin) with mathematicians and other scientists in many countries. He also performed extensive experiments to determine the acceleration of falling objects by comparing them with the swing of pendulums, reported in his Cogitata Physico-Mathematica in 1644. He was the first to measure the length of the seconds pendulum, that is a pendulum whose swing takes one second, and the first to observe that a pendulum’s swings are not isochronous as Galileo thought, but that large swings take longer than small swings.

Further recommended reading:
Andrew Kassebaum, Marin Mersenne: A Priest at the Heart of the Scientific Revolution, on Strangenotions

Christian Huygens: from microscopy to astronomy

Christiaan Huygens

On 8 July 1695, Christiaan Huygens (1629–1695) passed away at The Hague. A mathematician, physicist, and astronomer, he was also interested in philosophy and humanistic studies. In his mechanistic conception of light and gravitation he was inspired by Descartes’ thought. He knew Blaise Pascal with whom he corresponded about mathematical problems. He grappled with problems in plane geometry, optics, wave theory, and collision. He designed microscopes and telescopes and discovered Saturn’s rings, which Galilean observations had not yet been able to decipher.

Among others, Dutch physicist Christian Huygens introduced the concept of Entrainment in 1666 after he noticed that the pendulums of two clocks mounted on a common board had become synchronized, and his subsequent experiments duplicated this phenomenon. He termed this effect as “odd sympathy”. The two pendulum clocks synchronized with their pendulums swinging 180° out of phase (in opposite directions), but the in phase states were also observed. It is theorized that entrainment occurs because small amounts of energy are transferred between the two systems when they are out of phase in such a way as to produce negative feedback. As they assume a more stable phase relationship, the energy transfers are gradually reduced to zero. Within other topics of physics, Huygens’ theory of entrainment is related to the resonant coupling of harmonic oscillators, which also gives rise to sympathetic vibrations.

Entrainment has been used as a term to describe the process of mode locking of coupled driven oscillators, which is the process whereby two interacting oscillating systems, which have independent and different periods, assume a common period, which might be not only synchrony, but also other phase relationships. In general, the system with the greater frequency slows down, and the other speeds up. A 2002 study of Huygens’ observations demonstrated that his observation of an antiphase stable oscillation was somewhat fortuitous, noting that there are other possible stable solutions, including a stationary state where a clock stops running. Mode locking between driven oscillators can be demonstrated in labs by using mechanical metronomes on a common, easily movable surface. It is believed that many biological systems utilize such mode locking, including in the proper operation of pacemakers and other biological rate processes.

Sources: inters.org; wikipedia.
Painting: Christiaan Huygens by Bernard Vaillant (1632 – 1698)