Roger Bacon: A Franciscan introducing the experimental method


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On 11 June (?) 1292, Roger Bacon (1214–1292) died at Oxford, England.

He was a Franciscan monk who was one of the first to propose mathematics & experimentation as methods of science. Drawing on Latin translations of Aristotle and the writings Arab scientists, he described a repeating cycle of observation, hypothesis, experimentation, and verification. 

His interest in foreign languages and other philosophical traditions began as a student. Reading biblical manuscripts at Paris, he encountered discrepancies in the texts; thereafter, he endeavored to uncover their true meaning and assess their claims against the discoveries of the natural sciences. One biographer notes:

“He is never tired of pointing out the amount of injury done to the spread of knowledge, and to the Church in consequence of the utter neglect of these languages. He frequently reminds his readers that all science was originally revealed to the ancient Hebrews, from whom it descended to the Egyptians and the Greeks… ‘prima tradita est principaliter et complete in lingua Hebraea’ (Opus Tertium, x)… ‘Latini nullum textum composuerunt, scilicet, neque theologiae neque philosophiae… manifestum est necessarium fore Latinis, ut si volunt puro, et sano, et efficaci sapientiae liquore potari, quod in fonte Hebraici sermonis, et Graeci, et Arabici, tanquam in primitivis vasis, discant sapientiam exhaurire’ (Compendium Studii Philosophiae, vii.). He urges, therefore, the study of Hebrew and Greek, as being indispensable to the spread of true knowledge, to the preparation of accurate translations of the works of the ancients…”

Through the writings of Roger Bacon, the Church gave Europe the mindset needed to believe it could study and learn about the natural world through experimentation, rather than reason alone, utilized by the Ancient Greeks.

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Source: Nolan, Edmond & S.A. Hirsch. The Greek Grammar of Roger Bacon and a Fragment of his Hebrew Grammar. (Cambridge, GB: The University Press, 1902), xv-xvi.

Pierre Duhem, an uneasy genius

Pierre Duhem

Pierre Maurice Duhem (9 June 1861 – 14 September 1916) was a physicist, epistemologist, and historian of science. He maintained that the history of science and ideas is important for a correct scientific epistemology. He contributed to a reexamination of the role Christian theology played in the formation of the Western scientific spirit, chiefly through his monumental work “Le système du monde. Histoire des doctrines cosmologiques de Platon à Copernic” (10 volumes), whose publication was completed after his death. Duhem criticized the claims of the mechanist and materialist philosophies, stating that they operated on illegitimate extrapolations from results obtained in physics. He considered metaphysics the field of first principles and of the notions upon which physics is based, while leaving physics the full freedom to formulate its own models and delineations. His principal reflections on the relationships between physics and metaphysics are found in his work “La théorie physique, son objet et sa structure” (1906).

Stanley Jaki wished to increase our knowledge and appreciation for Pierre Duhem, writing the book Uneasy Genius: The Life And Work Of Pierre Duhem” (1984).


The Handkerchief Tree, the Great Panda, and a French Missionary

Davidia involucrata, branche fleurie

In late May/June, the Handkerchief Tree (Davidia involucrate) shows its unique flowers, tight clusters about 1–2 cm across, reddish in color, and each flowerhead wrapped up with a pair of large (12–25 cm), white bracts at the base giving it the aspect of a handkerchief, especially if gently moved by a little breeze. The flowers are lined up along the branches of the tree, giving the tree a spectacular look. Outside this short period of flowering it is a rather unimpressive tree, found in Botanical Gardens and parks, and native to China.

Armand David

It is named “Davidia” after the French Catholic priest and Lazarist missionary David Armand (Père David) who described the tree first and sent a dried specimen to France. Armand (1826-1900) was not only a missionary, but also a great botanist and zoologist. After his education in Bayonne (Basque country) he went to Paris to enter the congregation of the ‘Lazaristes’, who were missionaries. Between 1850 and 1862 he was in a Lazarist cloister near Genua, where he devoted himself to natural sciences. When in 1861 the Paris zoologist Milne-Edwards asked the cooperation of missionaries to collect animals and plants in – then still unexplored – China, the Lazarists sent Armand David to this country.

Once in China he made several large expeditions; in 1866 to Mongolia, in 1868-1870 in central China and Sichuan, and in 1872-1874 in Central and Eastern China. In 1874 he returned to France, where he settled down in the headquarters of the congregation in Paris. He published on his expeditions, and also a large work on the birds of China.

During his travels in China, he collected 13,000 specimens including 189 new plant and animal species, among these the handkerchief tree (Davidia involucrata), the butterfly bush (Buddleja davidii), Lilium davidii, Populus davidiana, as well as thirteen species of rhododendrons, three magnolias, four firs, and four oaks.

Great Panda

In March 1869, Père David discovered the Giant Panda near Baoxing (previously Moupin) in the Sichuan province of China. He wrote: “The young bear is entirely white, except for his four limbs, his ears, and the area around his eyes which are a deep black. Thus, we have here a new species of Ursidae that is very remarkable not only because of its color but also because of the hairiness under its paws.” The animal, which is mostly active at night and lives at an altitude of about 3,000 m in inaccessible areas, was very little known outside the local population. Despite there being a number of depictions of bears in Chinese art starting from its most ancient times, and the bamboo being one of the favorite subjects for Chinese painters, there are no known pre-20th-century artistic representations of giant pandas. It became very famous around the world, including China, only very recently.

In the midst of his work as a naturalist Father David did not neglect his missionary labours, and was noted for his careful devotion to his religious duties and for his obedience to every detail of his order’s rules. Back in France, he said:

“When I came to China, my great ambition was to share the harsh and meritorious work of the missionaries who, for three centuries, have been trying to win over the vast populations of the Far East to Christian civilization. But all the sciences which have for their object the works of creation tend to the glory of their author; they are praiseworthy in themselves, and holy in their object; to know the truth is to know God.”


Wikipedia: David Armand (English), David Armand (French), Handkerchief Tree, Giant Panda

Cédric Basset, In the Footsteps of Father David

Édouard Robert, Histoire de la Congregation de las Mission, Chapitre XXXV (1936)

Further recommended reading:

Bernard Scott CM, Père Jan Pierre Armand David CM

Francesco Denza and the Carte du Ciel


On 07 June 1834, Francesco Denza (1834-1894) was born in Naples. He was a Barnabite priest, astronomer, and meteorologist who immersed himself in solar spectroscopy and founded what later became the Italian Meteorological Society. He renovated the observation deck of the Vatican Observatory, founded in 1888. Vatican staff members realized that participation in the program ‘to map the sky’ would immediately give their young observatory international recognition. Pope Leo XIII commissioned Father Francesco Denza and Father Giuseppe Lais to attend the Astrographic Congress and enroll the Vatican as one of the participating institutions in the international Carte du Ciel project which made a photographic map of the stars.

Charles De Koninck on traces, fossils and science

Charles de Koninck

Charles de Koninck (July 29, 1906 – February 13, 1965) was a philosopher and professor at the University of Laval, Canada. Schooled in Aristotelian and Thomistic philosophy, he labored to show the compability and complementarity of philosophical knowledge and scientific inquiry.

He taught epistemology (the philosophy of knowing) and natural philosophy, and was named head of the faculty in 1939. He was the director of the department of the faculty until 1956, then again in the year 1964-65. He has published more than 160 academic works.

It is easy to see that traces of the past are most inadequate. We must distinguish the knowable traces from the known ones. Our science of history can only be based on known facts, just as cosmic reality only becomes formal object of physical science when it is measured. Now all this is unquestionably obvious. But let us not forget that it has taken scientists thousands of years to find out that measure-numbers are their object, and that physics must define properties by describing the process of measurement of which they represent the result. Historical research moves between the known and the unknown traces. This research might be called scientific when it is guided by a hypothesis, although in itself it is prescientific.

…. The cooling off of the earth has not only made life possible, it has preserved traces of life in its pleats. It is [at] a certain stage of evolution that nature begin[s] to make documents of life, and preserve it for the mind, that higher form of life. Man and the fossils are not just a coincidence. Life tends to reach itself.

Charles De Koninck, On Philosophy of History

Picture: “Ammonite Replaced by Marcasite”, Cephalopod-Ammonite Photos, R.Weller/Cochise Collegue. Charles de Koninck, The CDK project

Note: We share this text, originally shared on our fb page in 2016. The text is no longer available on the internet.

John Paul II to scientists bear witness to your fidelity to Christ!


On 25 May 2000, on the occasion of the Jubilee of Scientists, Pope John Paul II gave a talk to scientists gathered in St. Peter’s Basilica in the Vatican: “Men and women of learning, be motivated by the desire to bear witness to your fidelity to Christ! At the dawn of the third millennium, the rich panorama of contemporary culture is opening unprecedented and promising prospects in the dialogue between science and faith, as between philosophy and theology. Devote all your energies to developing a culture and a scientific approach which will always let God’s providential presence and intervention be disclosed.”


Nicolaus Copernicus: Knowledge of Creation as Worship to God


copernicus 01.jpgOn 24 May 1543, Nicolaus Copernicus (1473–1543) passed away in Frombork, Poland. He was a Polish mathematician and physicist.

A quote attributed to Copernicus (in multiple sources):

“To know the mighty works of God, to comprehend His wisdom and majesty and power, to appreciate in degree the wonderful working of His laws, surely all of this must be a pleasing and acceptable mode of worship to the Most High, to whom ignorance cannot be more grateful than knowledge.”

In 1533, Copernicus’ heliocentric system was explained to Pope Clement VII (1478–1534) and two cardinals by Johann Widmanstetter (1506–1557). According to historians, the Pope was so pleased with the work that he gave Widmanstetter a valuable gift as a sign of his gratitude.

Near his death, he turned his work On the Revolutions of the Celestial Spheres in for publication, in which he maintained the simplicity and mathematical coherence of the heliocentric system. The introduction to his work, written after his death by Osiander, emphasized (probably against Copernicus’ wishes) that the work was merely a mathematical exercise on the part of the author.