“Theory can be very useful as a way of piecing together what is unusual … It can help us interpret what we are finding. It can also lead to dead ends and wasted time and resources.”
Making Bog Bodies Dull
Two Catholic scientists from the 1400’s spent their lives working on a celestial problem using theories based upon the work of Ptolemy from ~150 A.D. and the result was wasted effort. Georg Peurbach and Johann Müller aka Regiomontanus both made immense contributions to geometry. They worked together. Both also expended a great deal of energy on Ptolemaic theories, writing textbooks and looking for better translations of the Almagest, and one can only imagine what they could have done if they had been able to use that intelligence on a better system. The University of Saint Andrew has lovely biographies of both. https://mathshistory.st-andrews.ac.uk/Biographies/Regiomontanus/ AND https://mathshistory.st-andrews.ac.uk/Biographies/Peurbach/
When I first investigated Catholic scientists down through the ages I was struck by how many of the ‘natural philosophers’ (what we think of as scientists) were driven by the need for reform of the Julian calendar. I could say it differently by pointing out that the Church funded many of these scientists, driven by its need for a better calendar. In his book, The Sun in the Church, John Heilbron made the point succinctly, saying the Catholic Church had funded more science down through the ages than any one else.
By the year 325 A.D. it was known that the Julian Calendar was off from the heavenly calendar by three days. The Council Fathers believed that Julius Caesar made a mistake when he started his calendar and they corrected this mistake by changing the calendar by three days. Over the next twelve hundred years, as the daily calendar once again diverged from the heavenly calendar, the Church as an institution was forced to realize that the Julian calendar was flawed. During this time there were long, long, long discussions about how to fix the calendar. According to this immensely detailed article in the Catholic Encyclopedia, besides the Council of Nicaea in 325, the calendar was brought up at the Council of Constance (1414-1418), of Basle (1431), the Fifth of the Lateran (1512-1517), and that of Trent (1545-1563). (https://www.newadvent.org/cathen/09247c.htm)
What this article pointed out, that I hadn’t paid full attention to, was that yes, the days were off, eleven days worth by the time all was fixed, but the cycle of the moon, particularly in reference to the earthly calendar was also not well-understood. Knowing when the full moon would happen was a vital part of the Easter formulation, given as “the first Sunday after the first full moon after the vernal equinox.” Medieval breviaries and missals included a universal calendar, which was supposed to give the date of Easter for hundreds of years ahead. Those dates were often in error.
It’s not easy to predict Easter ahead of time, but it’s easy to see when it’s wrong. Pope Pius V published a perpetual calendar in 1568 which was promptly withdrawn because it was so faulty. I find this particular example remarkable because it was only fourteen years later that the Gregorian calendar was published and it is considered to be accurate for about 3,000 years. The article goes into great depth and detail over the calendar arguments. My favorite lines include…
The consent of the princes had more influence with the pope than the opinion of scientists. To bring about an agreement of the latter was utterly hopeless
the Sorbonne not only rejected the “Compendium” but condemned every change in the calendar…
The Duke of Tuscany forwarded to the pope the judgments of several Florentine mathematicians, no two of which agreed among themselves…
Have a blessed Holy Week. The calendar is trustworthy.
The header image is from the National Gallery of Art. Christ Showing His Wounds to Saint Peter, the Magdalene, and the Good Thief. 15th century German woodcut. No artist. Public domain.
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