A Collection of Notkers

Notker Balbulus (the Stammerer)

Yesterday's post on cheese included an anecdote about Charlemagne, attributed to Notker the Stammerer. One would think that "Notker" was an unusual name in any day and age, but it turns out to have been very popular—especially at the Abbey of St. Gall. Ekkehard IV (c.980-1056), a monk of St. Gall, continued a chronicle that had been begun by others. Through the Casus sancti Galli (Doings of Saint Gall), we learn about the history of its inhabitants.

Notker the Stammerer (c.840-912) was called "delicate of body but not of mind, stuttering of tongue but not of intellect, pushing boldly forward in things Divine, a vessel of the Holy Spirit without equal in his time" by Ekkehard. He was a prolific writer, but the work he is most known for is a collection of anecdotes about Charlemagne that has been called a "mass of legend, saga, invention and reckless blundering." Supposedly, Notker wrote De Carolo Magno (Concerning Charles the Great) in honor of a visit to St. Gall by Charlemagne's great-grandson, Charles the Fat.* It is riddled with errors, such as when it claims that the Venerable Bede (672-735) devoted a book of his Ecclesiastical History to King Pepin the Short (714-768), who did not become a king until 752; when Bede died, Pepin's grandfather, Charles Martel, was king.

Notker Labeo ("the Thick-Lipped") was a nephew of the Ekkehard clan. He lived from c.950-1022 and had a reputation in the monastery as a voracious reader. He took up translating various philosophical texts into German, for which he was later called Notker Teutonicus ("the German"). When he died, he asked that he be buried in the same clothing he had always worn, to hide the fact that he wore a heavy chain around himself to mortify the flesh.

Notker Physicus, who died in 975, was called thus (according to the Catholic Encyclopedia) because of his very strict discipline. His knowledge of medicine is praised by Ekkehard, and he is probably the same Notker who was called Notarius (notable) who was known at the court of Emperor Otto I for his skill in medicine.

There was a Notker who was a nephew of Notker Physicus, of whom we know little except that he became Abbot of St. Gall in 971 and died 15 December 975. He was considered exceptionally pious.

Yet another Notker (c.940-1008) was the provost of St. Gall and became the Bishop of Liège. He established schools that became famous and drew numerous students. He is responsible for architectural projects, such as St. John's in Liège, designed after the Aachen Cathedral.


*Charles was the son of Louis the German, the son of Louis the Pious.

Time To Talk of Cheese

Cheese-making; molds can be seen on the left.

Warm up some milk, add an acidifying agent, let it cool, drain off the whey to leave the curds, and the result is cheese. We don't know who first made cheese—the best guess is that milk stored in a vessel made from the stomach of a ruminant became cheese accidentally—but it has been around for thousands of years.

The Romans loved cheese—especially fresh goat cheese—and Pliny has much to say about the different kinds from different parts of the Empire. As cheese-making spread—often by the expansion of Roman culture into Europe—local varieties developed due to differences in climate and bacteria.

Cheese was a good addition to the Christian diet, since it was protein-heavy and could be consumed on days when meat was not allowed. A Monk of St. Gall (identified as Notker the Stammerer) wrote a biography of Charlemagne called De Carolo Magno (On Charles the Great), full of glorifying anecdotes. It has a revealing story about the emperor that involves cheese:

Now on that day, being the sixth day of the week, he was not willing to eat the flesh of beast or bird; and the bishop, being by reason of the nature of the place unable to procure fish upon the sudden, ordered some excellent cheese, rich and creamy, to be placed before him. And the most self-restrained Charles, with the readiness which he showed everywhere and on all occasions, spared the blushes of the bishop and required no better fare: but taking up his knife cut off the skin, which he thought unsavoury, and fell to on the white of the cheese. Thereupon the bishop, who was standing near like a servant, drew closer and said, "Why do you do that, lord emperor? You are throwing away the very best part." Then Charles, who deceived no one, and did not believe that anyone would deceive him, on the persuasion of the bishop put a piece of the skin in his mouth, and slowly ate it and swallowed it like butter. Then approving of the advice of the bishop, he said: "Very true, my good host," and he added: "Be sure to send me every year to Aix two cart-loads of just such cheeses." [Book I, Chapter 15]

We cannot say which variety of cheese tickled Charlemagne's palate. Gorgonzola is mentioned in 879, and cheddar around 1500, but we don't know if 9th century Gorgonzola or 16th century Cheddar tasted the same as the varieties we eat today.

Medieval Cookery has a recipe for fresh cheese, and you can find more at the Medieval Cheese Forum.

The Rotating Earth

Nicholas Oresme

While re-examining Aristotle, Jean Buridan used observation and brainpower to anticipate some of the ideas we attribute to Galileo and Newton. He carried his ideas further when he put his mind to the question of the Earth's movement.

For most scholars of the Classical and early Medieval eras, the Earth was fixed, and the Heavens rotated around the Earth once each day. Buridan didn't like this: the Heavens are so much larger than the Earth; why would God design such an inelegant system? Moving the Earth would be easier.

Ptolemy knew this could not be, because if the Earth were rotating, there would be a constant rushing of wind as the air of the atmosphere passed over the land underneath it. Buridan scoffed at this: the atmosphere would be rotating just as the land does. There was no reason to dismiss the idea that Earth rotated daily.

For Buridan, however, empirical evidence was crucial. Of course, his predecessors argued, the Earth clearly does not move; we can see that. Buridan, however, likened the situation to being in a boat on a river. An observer on a second boat that was tied to the bank would see the first boat moving, but if the observer on the second boat could not see the surrounding landscape, then he would not know which of the boats were moving. The problem, Buridan knew, was that without an outside frame of reference, one cannot tell if it is the Earth or the Heavens that is moving. He needed an experiment, and he thought of one.

...and that's when he made his mistake.

Here was his idea: shoot an arrow straight up above your head. If it comes back down where you are standing, then the Earth is stationary. If the Earth rotated under it, then the arrow would come down somewhere off to the side.

He didn't realize that the same property that moves the atmosphere along with the ground would carry the arrow along as well. It would be Buridan's most brilliant student, Nicholas Oresme (c.1325-1382), who would realize and state that the arrow moves along with the Earth and atmosphere. Lacking a way to definitively prove his ideas, however, Oresme would ultimately fall back on the Bible for guidance on this issue.

One Soul To Guide Them All

Averroes (1126-1198) undertook to explain and comment on the works of Aristotle, in an attempt to clarify the Greek philosopher's concepts. One of those concepts was the idea of man's intellect, the debate over which was both stimulating and shocking for the medieval world.

Averroes (in turban); detail, "School of Athens" (Raphael)

Aristotle distinguished between a passive intellect, which is man's predisposition to accept and hold ideas, and an active intellect, which was the agent of analysis and creativity.* The active intellect was an outside force, and the blending or convergence of the external active intellect with the internal passive intellect differed in individuals, which is why we could strive to learn and think and better ourselves intellectually, but we were still different from each other. The connection between active and passive was not the same in each person. This accounted for different and individual personalities.

This was an obvious parallel to Aristotle's Realism: the idea that there exist "universal" abstract concepts—such as "dog"—outside of our direct experience, that allow us to directly experience multiple different dogs with different characteristics (which he called "particulars") and yet understand that they were all dogs.

Averroes explained this further, and created a religious controversy.

If the active intellect was external (and from a divine source) but the less-powerful passive intellect resided in man, and it was the blending of the two that created personality and human intelligence, then what happens at death when the external active intellect is removed? As a divine and lasting and (presumably) unchanging force, it stays as it is, unaffected by its temporary connection to an individual. The human-centered passive intellect dies with the human, the active intellect withdraws, and therefore there is no individual personality that exists anymore.

For Averroes, understanding Aristotle meant that there was no survival after death of a personality. Your personality—what makes you "you"—is gone when you die, and there is no room here for a soul with your personality to exist in an afterlife.

Orthodox Mohammedan theology did not agree with this, nor did Christian theologians such as St. Bonaventure and St. Thomas Aquinas.

Averroes defense against the charge of heresy? That reason forced him to express these thoughts, but that of course he adhered to the truth as explained by his faith.

*Aristotle used the term "intelligences" to refer to the non-physical (divine, or spiritual) forces that moved the celestial spheres. Christian thinkers would later call these "angels."

Nominalism vs Realism

Realism [link]

At the foundation of philosophy is a question: what defines reality? There are several questions that are connected to this. Let us start with: when we say that a lot of different animals are all dogs, to what quality are we referring that makes the Dachsund and the Great Dane both dogs? Is there an essential quality of "dog-ness"? Some universal concept that is inclusive of all dogs, despite the particular differences between breeds?

There it is: universals and particulars.

Realism says that both universals and particulars exist. That is, we recognize that different dogs/houses/trees are those things because, although they have different particulars, there is a universal essence of dogs/houses/trees that exists. Plato and Aristotle were Realists.

Nominalism says that the world is made only of particulars. Things we see are put into categories by our thought processes and our language, not by the existence of some abstract universal. William of Ockham and Jean Buridan were Nominalists.

In the two diagrams shown, we see that in Realism, although John and David have different Particulars, they are defined by their Universal quality as human beings. Nominalism, however, shows John and David only defined by their Particulars. The category of Humanity is created by us. There is no abstract "Humanity" essence that exists independent of John and David.

Nominalism [link]

Getting at the truth produced some fascinating thought experiments. One—The Puzzle of Theseus' Ship—was posed by Plutarch (46-120 CE). The ship of Theseus was preserved in Athens for several generations. As pieces of it decayed, they were replaced with new wood, so that the ship would stay intact. If a thing is based on its particulars, then with the particulars of this ship having changed over the years, is it still Theseus' ship? If there is some universal of Theseus' ship (as Realism says) then it is still his ship. If there are only particulars (as Nominalism says) then it isn't.

British philosopher Thomas Hobbes (1588-1679) took this a step further: if all the removed pieces were assembled into a complete ship, then which is Theseus' ship? Are they both Theseus' ship? He concludes that this would be absurd.

Even the early scholars understood that there were problems with these concepts, and struggled to reconcile the issues. Still, they did their best to understand how reality worked, and how that would help them to understand everything else.

...such as whether we have individual souls. That discussion will take us back to Averroes tomorrow.

The Commentator

Statue commemorating Averroes in Córdoba

Averroes (1126-1198) was born in Córdoba into a family of distinguished jurists and scholars at a time when Islamic culture was flourishing in Spain. He probably would have spent his life as a judge if not for his mentor and friend, the physician Abu Bakr ibn Tufayl, who told him that he should write commentaries on the works of Aristotle. The problem seen by ibn Tufayl was that Aristotle was too obscure either because of the ambiguity of his own writing or the shortcomings of his translators.

Averroes, whose real name was ʾAbū al-Walīd Muḥammad bin ʾAḥmad bin Rušd, embraced the task so thoroughly that, to the West, he became known as "The Commentator." His scholarship was embraced across cultures: Jacob Anatoli translated Averroes' Commentaries into Hebrew. Anatoli's colleague and friend Michael Scot translated some directly into Latin.

He analyzed and promoted most of Aristotle (and Plato's Republic) to the known world, as well as writing dozens of books of his own. So far as we know, he did not have access to original texts—there is no evidence that he knew Greek—and so his commentaries are based on Arabic translations of Aristotle.

Unfortunately for him, his rationalist views often got him into trouble when they came up against Islamic theology (which he had studied extensively). He was, in fact, banished by a caliph to whom he had been the personal physician, because some side remarks in Averroes' writing (such as "that Venus is one of the gods") struck the caliph as blasphemous. Fortunately, Averroes was allowed to return home prior to his death.

One of his most radical ideas, based on Aristotle, was that there were multiple intellects, but only one shared soul for all of mankind. To explain that raises more questions, however, unless first we look at a debate I have been putting off for months. Tomorrow, therefore, we will (finally) discuss Nominalism vs. Realism.

Jacob Anatoli

Daily Medieval has frequently mentioned the importance of Arabic texts in the transmission of knowledge to Western Europe. Arabic, however, was not a commonly known language, and Arabs did not have a strong presence in Western Europe. Arabic culture often brushed up against Latin culture in the southern Mediterranean, as mentioned Salerno, or when a scholar such as Michael Scot made it a point to learn Arabic. Scot probably had help in the form of Jacob Anatoli.

Jacob ben Abba Mari ben Simson Anatoli (c.1194-1256) grew up in southern France, and gained such a reputation for scholarship that he was invited to Naples by Frederick II, who gathered several other academics to his court, such as Scot and Fibonacci. Anatoli became known for his translations of Arabic texts into Hebrew, and he very likely aided Michael Scot in his Arabic translations. Roger Bacon explains that Scot was aided by a Jew named Andreas, and some scholars believe "Andreas" to be a misunderstanding of "Anatoli."

Of his non-translations, the greatest work is the Malmad ha-Talmidim (the title is a pun, being interpreted either "Teacher of the Students" or "Goad to the Students"). The Malmad shows a wide range of knowledge, incorporating the Old Testament and Jewish commentators, but also the New Testament, Aristotle, Plato, and Averroes. His egalitarian approach to Christian and Muslim matters was refreshing, but Judaism still had special status; he wrote "the Greeks had chosen wisdom as their pursuit; the Romans, power; and the Jews, religiousness." He tells us that a non-Jew who seeks religious Truth should be respected by Judaism and not mocked.

Anatoli extended this intellectual courtesy to Frederick II, incorporating remarks by the emperor in his works. He also mentions a Christian whom Anatoli considers a second master (after Anatoli's own mentor, Samuel ibn Tibbon); this "master" has been equated to Michael Scot.

As for his Arabic translations, Anatoli's crucial contribution was exposing the West to the work of Averroes, one of two Arab scholars (the other was the medical expert Avicenna) whose work is considered fundamental to the Middle Ages.We'll look at Averroes tomorrow.

Defeating Eternity

How long has the universe existed? Has it been around forever? Did it have a beginning? Could it have a beginning? These questions troubled the ancients.

Aristotle in his Physics tried to answer this through reason. Everything that comes into being does so from something that already exists; matter is made from matter, after all. The matter of the universe would have to come into being from some underlying matter; it couldn't come from nothing. For the matter of the universe to come into being, some matter must have existed before it. This statement is ridiculously self-contradictory, and therefore could not be taken seriously. The universe must have always existed.

Others supported Aristotle. Critolaus (c.200-c.118 BCE) couldn't believe that human beings would ever stop simply procreating into eternity. In the Early Medieval Period, Proclus (412-485) produced De Æternitate Mundi (On the Eternity of the World) with 18 proofs.

This belief was about to collide headlong with Christianity, however. The Bible makes it clear that there was a moment of Creation. That being the case, the universe cannot have been eternal.

John Philoponus (490-570) was a prolific and controversial writer who realized that Aristotle needed to be questioned on some things. Although he would be condemned after his death as heretical for interpreting the Trinity as three gods instead of one God, he was known in his lifetime for defending the Biblical necessity of a universe with a starting point. He wrote "Against Proclus" in which he challenged every one of Proclus' arguments. The basis for his argument is simple, and referred to now as the Traversal of the Infinite. If the existence of something relies on the existence of something else prior to it, then you need to account for the existence of the prior thing. That prior thing would rely on the existence of something before that, and so on. You have to have an infinite series of assumptions that something existed before the thing that came afterward, and never actually explain where any of the substances came from. The world could not possibly be infinite, and must have been created by a divine being.

The Ring of Fire vs. The Flood

15th century portrayal of Ptolemy's map

Prior to the Age of Exploration, human beings in the western hemisphere did not attempt to travel long distances by sea and discover distant lands.* This was partially because ships that could handle a very long voyage were not able to be built or provisioned easily for such a journey.** Another reason is that the world was "known" to be shaped so that long voyages were fruitless.

Eratosthenes (c.276-c.195 BCE) had established in the Classical Era the spherical nature of the Earth through simple and clear experimentation; no one disputed that. (His math on Earth's diameter was probably a little off: the unit of measurement he used probably gave him an Earth 4000 miles larger around than it is.) What was up for debate was the question of what existed "over the horizon."

Aristotle (384-322 BCE), upon whose scholarly shoulders the Middle Ages tried to stand, loved symmetry. It made sense to him that there were five zones (from the Greek word meaning "girdle") around the Earth. The extreme top and bottom were icy cold and uninhabitable. Just inside of them were the temperate zones where humans and animals lived—note: he believed both temperate zones were inhabited. In the middle it was so hot—and clearly, the further south you go from Greece and the Mediterranean the hotter it got—that it was uninhabitable. Pliny (23-79) said that this central zone was so hot that it was actually a ring of fire and was unlivable and impassable, so we would never be able to visit the people living in the southern hemisphere.

Wait, said Christianity. That can't be. The Flood covered the whole world, and when the waters receded, the Ark of Noah came to rest on Mt. Ararat in Turkey, from which all the animals strolled away and repopulated the world. If the ring of fire at the equator is impassable, how can there be animals living beyond it? Worse, if there are people living in the southern temperate region, how are we going to reach them with the Word of God?

Proving that classical scholars did not always agree, Ptolemy presented different problems in geography. His Geography was translated and made available to Western Europe in 1406. His map (depicted above in a 15th century version printed in Ulm) showed that all you had to do was sail far enough south to reach the southern lands in the world, but he also extended the bottom of Africa eastward, enclosing the Indian Ocean. This meant you could not sail to the Indian Ocean and therefore to India, but would forever have to use the Silk Road (and incidentally pay tolls at every border crossing, something sailors get to avoid).

The Age of Exploration changed all this. In 1473, Aristotle was proved wrong with a Portuguese ship exploring the west coast of Africa passed south of the Equator. In 1488, another Portuguese ship sailed around the Cape of Good Hope and reached the Indian Ocean. India and the east were accessible by ship after all, and the Portuguese quickly established those shipping routes.

Ptolemy's Geography was erroneous in another way. He estimated the Earth's circumference at thousands of miles smaller than Eratosthenes. Since no one cared to duplicate Eratosthenes' experiments and determine the distances involved, Ptolemy might have been taken as truth by some. His estimates of the size of a spherical Earth would put Asia thousands of miles closer to Europe by sailing west. With Portugal dominating southern routes to the East, was it Ptolemy's miscalculation that prompted Spain's Columbus to try a bold plan to establish a different and (he thought) shorter route?

*Perhaps some day we'll get to some of the rare cases of accidental discovery of previously unanticipated lands.
**I have been aboard replicas of Columbus' ships; they are frighteningly small considering the journey they made.

William of Ockham

The goal of Daily Medieval is to present a sampling of the infinite array of information about the Middle Ages in small, digestible amounts. It offers a taste of the thousand years of people, events, and ideas that don't get covered in the streamlined history books of standard academic courses. To that end, it tries to avoid those things that people "already know" and focus on the lesser-known lights that shone at the foundation of modern civilization. Sometimes, however, the obscure overlaps the well-known, and I find myself "forced" to write about something or someone that I worry is known well enough that the daily entry won't give the reader anything "new." My goal then becomes to broaden the reader's knowledge in unexpected ways.

Which brings us to William of Ockham. I would be surprised if readers of Daily Medieval had not heard of Occam's (or Ockham's) Razor, a guiding principle that says one should not make more assumptions than absolutely necessary to try to explain something.

William of Ockham (c.1285-1349) was responsible for so much more, however. Believed to have been born in Ockham in Surrey, England, he wrote about metaphysics, logic, theology, politics, and more. All this writing, however, happened when he left Oxford University in 1320 without a degree in theology. The prevailing theory for this unexpected departure is that he would not acquiesce to changing his commentary on the Sentences of Peter Lombard, a common part of the final examination for university students.

The basis for the theory is how the situation blew up years later. Ockham was summoned to Avignon to appear before Pope John XXII and a committee that would examine his writings. The committee, chaired by John Luttrell (an ex-chancellor of Oxford) found 51 heresies among William's commentary on the Sentences. It is believed that William escaped punishment by appealing to the Holy Roman Emperor (at the time, Louis IV), who was not always on good terms with the pope, saying to him "You defend me with the sword and I will defend you with the pen." In effect, he placed at the disposal of the Emperor his intellectual gifts, which (if this story is true) must have been known to be considerable for this ploy to work.

How did William earn his intellectual reputation? Between leaving Oxford in 1320 and arriving in Avignon in 1324, he spent three years in a Franciscan monastery, writing prolifically. One of the topics he put his mind to was whether priests should be allowed to own property. Franciscans believed priests should live a life of poverty. This put them into conflict with Pope John XXII, so the summons to Avignon and condemnation may have had more to do with that question than his Oxford writings.

Besides challenging the Church's ideas about material wealth, he was also challenging the ideas of people like Thomas Aquinas that reason was sufficient to determine everything we needed to know about the world.

But that's a story for another day.

He Who Would Be Santa

15th century woodcut of Nicholas

In the introduction to Arian Christianity I mentioned how discussion at the Council of Nicaea in 325 became so heated that Bishop Nicholas of Myra slapped Arius' face. Much of what we think we know about Nicholas is difficult to substantiate, but this has not stopped historians from talking about him. In fact, it is the least-documented information we have that has developed his reputation the most.

Nicholas (c.270-6 December 343) was born at Patara, in Asia Minor. As a young man he made a pilgrimage to Egypt and Palestine; upon his return he was made Bishop of Myra, not far from his city of birth. During the reign of the Emperor Diocletian, Nicholas was imprisoned, but freed once the Christian Emperor Constantine came to power.

He attended the first ecumenical council of the new Catholic Church in 325, which was called by Constantine in order to determine the (in)validity of Arianism (see the link above). Nicholas is counted among the numerous men who assembled there, and (as mentioned) became passionate about the debate.

Well, that's the story anyway. There are some lists of participants on which his name is not found, casting doubt on his presence at Nicaea. But his importance to legend is unquestioned. His popularity as a saint in Greece and Russia began early. Emperor Justinian I (483-565) built a church to Nicholas at Constantinople. He was revered in Germany during the reign of Emperor Otto II (955-983).

And you know you're an important person when they dig up your body in order to keep it safe (as monks had done in England with St. Cuthbert). In 1071 the Turks took control of most of Asia Minor. Among other things, this meant losing control of the burial site of Nicholas. Byzantium regained control under Emperor Alexios I Comnenus, but sailors from Bari in southern Italy took it upon themselves to save the saint's bones. They brought the relics to Bari in 1087, where they have remained. (Actually, they brought the major bones, leaving fragments. Venetian sailors during the First Crusade brought the remainder to Venice where they were put in a church. Scientific investigation in the 1990s proved that the bones in Bari and Venice belong to the same man.)

Traditional pawnbroker sign

The chief story of his giving nature—the story that eventually gave rise to the legend of Santa Claus—is about a man with three daughters for whom he did not have enough money for dowries. Without a dowry, marriage was unlikely, and the fear was that they would wind up as prostitutes in order to support themselves. Nicholas passed by on three consecutive nights and each night threw a bag of gold in the window, saving the future of the daughters. Because of this he has been made the patron saint of (besides children and sailors, etc.) pawnbrokers; some think the traditional image of three golden balls for a pawnbroker shop is because of the three bags of gold. A 15th century woodcut now in the British Museum (see image above) shows Nicholas laying three gold balls instead of bags into the girls' bed. (An alternate theory has the three balls connected to the Medici family heraldry.)

His feast day is today, December 6. In some countries, children put their shoes outside their doors on the evening of the 5th, and on the morning of the 6th find chocolate, coins, or trinkets.

Final Exams

Early copy of the Sentences

In the Middle Ages, The Bible was recognized as the most important book in existence. No book was more discussed and commented upon. Many of the commentaries themselves, such as those of the Early Church Fathers, became only slightly less significant objects of study. The Early Church Fathers did not always agree, however, which led to confusion, and (if you weren't careful in your reading and expounding on what they said) to heresy. Into this dilemma stepped Peter Lombard.

Peter Lombard (c.1095-1160) was born in Italy. He studied at Reims and Paris, and taught for ten years in the cathedral school at Notre Dame where he would have met some of the greatest theologians of the time. He was ordained by 1156, and was made bishop of Paris in 1159.

At some point he found time to write. Although he wrote commentaries of his own, his great work was the Libri Quatuor Sententiarum (Four Books of Sentences), in which he attempted to cover the entirety of biblical scholarship and knowledge by laying out passages from the Bible with relevant commentary from the Early Church Fathers and others. He tries to show where there is agreement among the commentators; where there is disagreement, he tries to reconcile the opposing viewpoints.

The four books covered the Trinity, Creation (and the world), Christ and salvation, and the Sacraments. The Sentences became the standard theology textbook for the next 400 years, and formed the basis for understanding the Bible and Christianity.

Because of the fundamental position the Sentences takes in theology, it was at the center of most theological study. Therefore, students were given a simple task: write your own commentary on the Sentences of Peter Lombard. Your masters would read your commentary to see if you understood the Bible and its learned analyses properly. If you did not, you were told to correct your commentary. If you corrected your commentary, all was well and good. If you decided that you were right and that you should argue with your masters, you ran the risk of (at the very least) not having your degree conferred, or (at worst) being declared heretical.

...and that's what one of the most famous medieval thinkers—the one whose name everyone today knows—did, and it got him expelled from Oxford University.

But that's a story for another day.

Pre-Inertia

Expositio & questiones manuscript

Jean Buridan (c.1300-c.1361) was a University of Paris scholar who was not afraid to tackle some of the big scientific and philosophical issues of the day. That meant, in some cases, taking a critical look at one of the most revered figures in science and philosophy, Aristotle. Buridan, like William of Ockham (c.1288-c.1348),  believed in the observable reality around him, and believed that observation of the world was the key to understanding it. Challenging Aristotle could be risky, but as more and more scholars observed the world around them, they realized that Aristotle's theories needed amendment. He wrote Expositio & questiones (Expoition and questions) to analyze Aristotle's work.

For example, Aristotle believed that an object set in motion—let's say, a rock thrown by a human hand—continues to move after it has left the hand because there must be some continuous external force exerted on it. He theorized that, in the same way a hand swished through water creates little eddies and swirls in the water around it, so the rock's movement is continued by eddies and currents of the air. If there were no movement in the medium that helped carry the rock forward, he believed, the rock would stop its forward course (and presumable drop the the ground). The currents eventually faded, allowing the rock to end its forward flight.

Buridan was not satisfied with this. Building on the work of others (such as John Philoponus and Avicenna, both of whom deserve their own entries some day), he believed that there must be a property in the rock itself that accounts for its action once it has left the motive force of the hand. He called this property of the object impetus (from Latin impetere, literally "to rush toward, to attack").

The property or quality of impetus was clearly changeable. To hurl a heavy rock required you to give it more impetus than to hurl a pebble. Also, impetus was obviously used up over time, allowing the rock to cease its movement and fall. He also explained that a falling object gained impetus the longer it fell (are you paying attention, Galileo?). Unlike Aristotle, who believed that the medium of air in which the object moves helps it along, Buridan saw the air as resistance, causing the object to use up its impetus.

He expanded this theory by looking up. A question had bothered some philosophers for ages: why don't the planets slow down? Will they move forever? Buridan extrapolated his theory to say that a thrown rock in a vacuum would experience no resistance and its impetus would last indefinitely. If the planets were moving in a vacuum...

Well, actually, he couldn't go that far. He agreed with Aristotle that a vacuum couldn't exist in space, since there was no container to keep matter from rushing into the empty area. If above our atmosphere were filled with quintessence, however, Aristotle's "fifth element" that was pure, unchangeable, and frictionless, then the impetus imparted to the planets by whatever initial agency would continue to move forever! The idea of an eternal universe was supportable by science!

Buridan's Ass

Buridan's Ass is the name given to a paradox: that a hungry and thirsty ass placed exactly in the middle between water and hay will be unable to choose because neither choice is preferable or closer; he will therefore die of thirst and hunger. The paradox is named for Jean Buridan (c.1300-c.1361), who studied and taught at the University of Paris. He had a reputation for being a bright and charismatic figure who had a way with the ladies, but that last part might have been spread by his detractors.

But Buridan, who wrote several works including answers to puzzles such as the liar paradox, never discussed the dilemma of the ass; he might have, because it had been around for hundreds of years.

Aristotle mocked the paradox in his De Caelo (On the Heavens). There was an idea circulating that one could explain the unmoving nature of the Earth simply because it was round and centered among all that existed, and therefore all forces acted upon it equally, maintaining an equilibrium. Aristotle mocked this idea by saying it was as ridiculous as if to say that "a man, being just as hungry as thirsty, and placed in between food and drink, must necessarily remain where he is and starve to death." Other early philosophers commented in this dilemma as well.

Why did it get ascribed to Buridan? In his works, he does consider that a rational choice could not be made by a rational person between two equally good options:

Should two courses be judged equal, then the will cannot break the deadlock, all it can do is to suspend judgement until the circumstances change, and the right course of action is clear.

This was just a "thought experiment" for him, however. He did not believe this would in fact lead to total inaction: he believed in a moral determinism that would lead one to a choice, even though that choice or preference might come through an unknowable thought process. Later writers mocked him by laying the burden of the ass paradox on him.

Buridan and Aristotle would cross paths on another issue, however: when a thrown object leaves the hand of the thrower, what keeps it moving? Aristotle had a theory that was clung to by many for centuries. Buridan had a different idea, one that anticipated Newton by about 300 years.

But that's a story for another day.

A Byzantine Princess

Anna Comnena in Byzantine mosaic

Anna Comnena (1083-1153) was the daughter of an emperor (Alexios I), the wife of a Caesar, and the mother of a Grand Duke. For many princesses in history, that would have been a sufficient claim to fame. For Anna, however, these were merely incidental facets of her life; she was so much more than a link in a dynastic chain.

For one thing, like most Byzantine royal children, she was well-educated in history and literature, rhetoric, and the sciences such as astronomy and math. Medicine was to become her specialty, however: her father established a hospital in Constantinople where she taught medicine and treated patients, including her father in his final days. Her fame was known to Sir Walter Scott, who said of her:

During his latter days, the Emperor was greatly afflicted with gout, the nature of which has exercised the wit of many persons of science as well as of Anna Comnena. The poor patient was so much exhausted that, when the Empress was talking of most eloquent persons who should assist in the composition of his history, he said, with a natural contempt of such vanities, 'The passages of my unhappy life call rather for tears and lamentation than for the praises you speak of.' [Sir Robert of Paris]

Whether we can trust Scott's characterization of the Emperor's attitude toward his biography—and whatever her reputation for medicine—what is true is that Anna is best known to us for a fifteen-volume history of her times. True, it was begun by her husband, Nikephorus Bryennius, who was calling it Materials for History, but Anna turned it into an encomium for her father and his ancestors and finished it (as it has come down to us in history) as The Alexiad. Although she was not an eye-witness to much of what she describes, and is surely using hearsay (and filtering through her personal lens that saw her father in a better light), it is still the definitive first-hand work on that period in Byzantine history.

A rare example of political and military history produced by a woman, one of the insights it offers is the Byzantine horror at the masses of Western Europeans come on Crusade to disturb the peace of the Eastern Mediterranean. Although she wrote it decades after the fact, she would have seen the Latin armies approaching, and watched the siege of Constantinople in 1097, when her husband (at 14, she was already married) defended the walls of the largest city in the world against Godfrey of Bouillon (c.1060-1100), before Godfrey went on to conquer Jerusalem.

She also believed that she should have been empress and tried to make it so, but that's a story or another day.