Asking Questions

Image from Adelard's translation
of Euclid's Elements of Geometry

Being inquisitive is the first step to learning.* In the early Middle Ages, the presence of many classical authorities circulating in Latin, such as Aristotle and Plato, eliminated the need for inquiry in the opinions of many.

The 12th century saw an influx of more works, many of them Greek writings (preserved by Arabs) or Arab writings. The widening of philosophical and scientific horizons by this wave of knowledge caused many scholars to re-think what had been established.

Adelard of Bath (c.1080-c.1152) was an English philosopher who was in a position to translate into Latin for the first time many of the Greek and Arabic works becoming available to the West. After studying at Tours and teaching at Laon in France, he traveled for seven years through Italy, Sicily, Syria and Palestine. He translated Al-Kwarizmi's astronomical tables and Euclid's Elements of Geometry from Arabic, wrote works on the abacus and on his love of philosophy, and a book called Questiones Naturales (Natural Questions) in which he tackled, in dialogue form, 76 questions about the world. One of his themes is the choice of using reason rather than merely accepting authority.

For what should we call authority but a halter? Indeed, just as brute animals are led about by a halter wherever you please, and are not told where or why, but see the rope by which they are held and follow it alone, thus the authority of writers leads many of you, caught and bound by animal-like credulity, into danger. Whence some men, usurping the name of authority for themselves, have employed great license in writing, to such an extent that they do not hesitate to present the false as true to such animal-like men. [...] For they do not understand that reason has been given to each person so that he might discern the true from the false. [Questiones Naturales, VI]

To be clear: Adelard's science is not ideal: his periodic table of elements contains only four substances, which are mixed in various proportions to create all materials. Some animals see better by day or night because of either white or dark humor in their eyes. We see because an extremely light substance (Plato's "fiery force") is created in the brain, gets out of the brain through the two eyes, swiftly reaches an object and learns and retains its shape, then returns to the brain through our eyes so that we "see" what is in front of us. A mirror, whose surface is smooth, bounces back the fiery force, which on returning to us picks up our image on its way and allows us to see our reflection.

Still, his works were copied and distributed, and influenced much of what was to come. His assertion of reason over blind acceptance of classical authorities was an important milestone in scientific thought. Many of his ideas are seen again in the writings of Robert Grosseteste, Roger Bacon, and Hugh of St. Victor. Once the printing press was perfected, Adelard's translation of Euclid became a standard text for a hundred years.


*One of the followers of this blog is part of a group trying to promote inquiry-based learning in young people. Visit Prove Your World to learn more.

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!

Natural Philosophy

William of Conches (1085-1154), as mentioned yesterday, wrote on Plato's Timaeus. The Timaeus was a popular work or analysis because, for a long time in the Middle Ages, it was the only work of Plato accessible to scholars. Medieval scholars, looking to create a "unified theory" of the world, did not want to reject material from the venerated philosophers of the past—even if they were pagan. Instead, they tried to reconcile earlier writers to Christianity to make a complete picture.

Natural Philosophy—the attempt to explain how the world works—had its own goal of reconciliation: to explain how a world where choice was possible could co-exist with a God who oversaw and was the motivator of everything that happened. There is an idea that science and religion find themselves in conflict because determining physical causes is pointless in a world where God determines everything. The classic example of this is: what should a good Christian do if he becomes ill? Should he visit a priest or a doctor? Is illness a divine punishment for sin, or best understood as a physical failing that can be treated?

In the Middle Ages, of course, the sufferer would not take chances, and would visit both. But men like William of Conches wanted to bring these two sides intellectually into agreement. He recognized that God was the ultimate cause: His omnipotence made him the primary cause that underlies everything in the universe. As a natural philosopher, however, William drew a distinction between this aspect of God and His methods for achieving His aims. There are actions, he said, that are secondary causes.

For instance, if I put a kettle with water on the stove to make tea and turn on the flame, my actions will cause the water to boil. A natural philosopher can examine the boiling water, measure its temperature, gauge the length of time it takes to boil and how active the boiling is, and find uses for boiling water. Those are all secondary causes and effects, however; the primary cause is my desire to make tea and my application of heat. The natural philosopher can learn about heat and water without knowing about my desire for tea. If he observes the water heating several times, he will learn to predict the outcome through his understanding of natural law.

What about miracles? Well, a miracle is an event that we recognize happens that contravenes natural law; in order to recognize a miracle, however, William said we first need to thoroughly understand natural law. By analyzing natural laws, the philosopher does not challenge God's authority; he is analyzing the secondary causes, with the understanding that they are an "additional layer" between God and the world.

Given that miracles are possible, however, does this invalidate our observations of natural law and are reliance on our predictive ability regarding them? For his part, William was very clear: he believed that God was loving and consistent, rather than capricious. The natural laws that God established would remain natural laws forever. The few times we observe something different are either a miracle—an anomaly that we do not have to understand, or merely more information that will enhance our understanding of natural law.