Gaia -- the Earth System
A Beginning --
It is always difficult to know where to begin. One might expect that the best place to begin is the beginning. After all, scientific knowledge constantly builds on what is known before. It should, then, be fairly easy to create a linear course that begins at the beginning -- the first scientific idea, and traces its development to the end or at least the present. I have several problems with this approach. I don't know enough to teach about all scientific knowledge. I don't even know what the first scientific idea was. More importantly, I'm not a very linear person. I don't think in straight lines, and I doubt if very many scientists do. I know that Science (with a capital S) doesn't work that way. Yes, science builds on what was known before, but the new knowledge doesn't just build on the old, it changes it or maybe if we're talking about a scientific revolution, trashes the old ideas all together.As a result I thought I would compromise and start somewhere in the middle with the Trial of Galileo. I like this point in time because Galileo's story, even though it is 400 years old, still has meaning today. The same conflict between scientific and dogmatic knowledge that resulted in Galileo's trial and punishment continues today. For example, when the religious right attempts to prevent the teaching of evolution in high school biology, it is replaying the role of the 16th century Catholic Church by trying to control ideas. Galileo's trial also makes a good beginning because it can be used to help explain what science is and how scientific knowledge is different from other ways of knowing our universe.
First, a couple of asides:
1. This class is intended to be a little different from most introductory science classes. It will not stress vocabulary, although there is no way to learn about science without also learning some of the technical language. Some scientific terms are a shorthand for very complicated processes or ideas. For example, consider the word, gravity. Try explaining why a ball falls without using some form of the word gravity. I might say the mass of the ball is attracted to the center of mass of the Earth and, therefore, moves toward it until it meets a solid object (the ground) that resists its motion. At this point the ball will either bounce or come to rest. Of course in attempting to avoid the use of gravity I introduced additional terminology -- attraction, mass, center of mass, solid, motion, rest. Some of the terms are more familiar than others, but each of these words has a very exact scientific meaning. So by not using the word gravity, I may be introducing new confusion to the problem. It would be a lot simpler just to say the ball falls because of gravity.
Another way in which this class will differ is that it will be built around understanding specific events or ideas or processes that occur in nature. In the first lecture the event is the trial of Galileo. Now, very few events occur in a vacuum and so it is important that you, the student, know the setting in which the event occurs and the rules that govern the actions shaping the event. Usually I will try to give you the background information that you need, although sometimes I'll expect that you already know this background material or have the ability to discover it on your own. For some topics this information will be quite detailed. For example, you'll need to know how the Earth formed and the Laws of Thermodynamics before you can understand both the brilliance of Lord Kelvin's experiment and the mistakes he made. Other topics will require knowledge of geology, meteorology, or oceanography. By the end of the course you should know quite a bit about the Earth and how it works and about the methods that scientists use to explore the Earth and its systems. I especially hope that you will learn to use these tools to think about the world and your place in it.
2. This is a science course. I will, therefore, expect you as an active participant in this class to learn and use both scientific methods and knowledge. I recognize that there are other ways of knowing. The Zen exploration of the inner-self is real and has value, as are strongly held religious beliefs based on faith or church dogma. However, because neither is based on scientific investigation, a process of thought, observation and testing, they are not the subject of this course. If you feel that your beliefs may conflict with your ability to participate successfully in this class, please see me as soon as possible.
Setting the stage:
The end of sixteenth century (the late 1500's) was quite different from the end of the 20th. The European Renaissance, the rebirth of European civilization, was in full swing, bringing many changes to the political and intellectual landscape of the time. One of the great political powers was the Catholic Church, but it's power was being challenged by new ideas. So, as might be expected, it sought to maintain its power through a number of means. One of these was the Inquisition, or the questioning.
The Inquisition gets its name because the Church questioned the faith of an individual using tests that could be quite horrific. Torture was common. And, if one failed the test of faith, the heretic was liable to be burned at the stake in the hopes that the flames of this Earth would provide salvation from the fires of eternal damnation. In Spain the Church and the Crown used the Inquisition to consolidate their power in the newly united country by silencing the political opposition and through confiscation of the wealth of those found lacking in their faith. In the latter regard, the Jews of Spain were a particularly attractive target. They had gained considerable wealth in the 14 centuries since their banishment from Palestine, living in peace with both Moor and Catholic. However, because a Jew could not profess faith in the Catholic God, they were forced to either flee the Inquisition or be burnt at the stake. In either case the Church and the Crown shared the property and wealth they left behind. Queen Isabela used a small part of these gains to finance the expedition of an Italian sailor looking for a new route to the Indies.
Wealth is one avenue to power, but ideas are another. As a result, the Inquisition was equally concerned with controlling thought as it was with money. In ancient Greece, scholars had thought about the world in very scientific ways. That is they asked and tried to answer questions about the world using observation and experimentation. For example, they had not only proven that the Earth was round, they had accurately measured its size. However, the Greek intellectual pursuits were supplanted during the period of Roman rule by technological advance. Science took a back seat to engineering. The Romans were great miners and road builders, but they didn't have many new ideas. And, the Early Christians who eventually became the rulers of Rome were the epitome of anti-intellectuals. There was no need to learn about this world when our only object in being here was to get to the next. In fact it was heretical to do science. To ask questions about the Earth, to try to learn what might make the moon rise and set or why a thrown ball travels a particular path was to offend God. To even attempt to discover the Laws of Nature was seen as an attempt to diminish God because God should not have to obey any Law. Truth and knowledge were revealed through faith and revelation not experimentation. Over the centuries, the Church created a body of knowledge based on revelation and interpretation of the Bible that could not be questioned by members of the church.
Conflict between Church dogma (unquestionable knowledge based on faith) and intellectual pursuit began when Medieval Europe rediscovered the books of the Classical Greek scholars. The search for ideas that had motivated the Greeks caught the attention of the new intellectuals of Europe. One of these was the Italian mathematician, experimenter and teacher, Galileo. For the most part, the Church did not interfere with the intellectual rebirth of the Renaissance. In fact many in the Church were heavily involved in the development of new ideas and many of Europe's leading intellectuals were churchmen.
However, the idea of using observations and experimentation to answer questions was bound to lead to conflict. There would come a point where religious and scientific knowledge would clash simply because dogma is knowledge that cannot be questioned, and science is knowledge that must be questioned. Once the questioning begins there is no turning back because an answer cannot be wished away or made false by decree. Nor is it possible to decree certain topics off limits. The questions that scientists ask and the answers they find are often sparked by chance observation. So science was destined to come into conflict with the Church. It was Galileo who brought the issues to a head.
The Trial of Galileo
Dogma and science fought in the heavens. The Church had incorporated into its dogma an Earth-centered model of the heavens in which the stars, planets, sun and moon circled the Earth on spheres of different radii. This Ptolemaic model worked fairly well. It certainly seemed to fit our common perceptions that the sun rises and sets each day. However, as astronomical observations improved, the model became more and more complex in an effort to match the observations that were being made. Venus and Mercury were especially troubling because they had to circle the Earth on circles that circled the Sun. The complexity of the model led the Polish astronomer, Copernicus, to propose that the Sun, not the Earth was the center of the universe. This idea was much simpler. Each planet, including the Earth, traveled on a simple circular orbit around the Sun. And, while simplicity is often the goal of scientific theories or explanations, in and of itself it is not proof that one model is correct and another wrong.
Convincing evidence came with the invention of the telescope. Galileo seems to have immediately recognized the power of the instrument, both as a practical device for identifying ships at sea and as a scientific tool for improving our view of distant objects in the heavens. Looking at the sun he saw sunspots. Looking at the moon he saw craters. And most importantly looking at Jupiter he discovered that Jupiter had 4 moons that orbited Jupiter not Earth. If you have binoculars, you can see what Galileo saw. Consult an astronomy magazine or Natural History to find out when Jupiter is visible and where it is in the sky. Then on the next cloudless night take a look through the binoculars and you will see not only Jupiter but 3 or 4 small bright points of light. If you look just once you might think they are small stars, but if you look again the next night, you will see that the points have moved closer to or farther away from Jupiter. If you keep track of their positions, you can prove to yourself that they are orbiting Jupiter. The key point was that Jupiter's moons orbited Jupiter not the Earth, evidence that the Earth is not be the center of all motion in the Universe. Using these new observations, Galileo published a support of Copernican theory. The most respected scientist of Europe was saying Church Dogma was wrong, that the perfect knowledge of the Church was imperfect.
It interesting to note that if the Church had held that the Earth-centered universe was a scientific theory, Galileo's discovery need not have been so damaging. Theories are often found to be inadequate. Someone makes an observation that is contrary to what the theory predicts. At this point, science has a choice. It can throw out the whole theory and start over from scratch, or it can make a few changes in the theory -- minor adjustments -- to bring theory back into line with reality. If the theory has proven useful in the past, it is likely that most scientists would prefer to tweak the old theory rather than to discard it entirely. It is also possible that had the Church been stronger, it would not have felt it necessary to try to squash the new observations and ideas. But Protestant revolt in northern Europe and internal political strife weakened the Vatican and so it felt it could not allow the new ideas of Galileo to become common knowledge. If you are going to claim that your knowledge comes from God, you have to get it right the first time. To admit error would be to admit weakness and imperfection.
To solve the problem, the Church tried to put the "genie back in the bottle." Galileo was brought to Rome and showed the devices of the Inquisition. He was then asked to admit that he had made a mistake when he wrote that the Earth was not the center of the Universe. Being a reasonable man, Galileo agreed that he had been in error. Being a proud, perhaps arrogant, man, he no doubt thought he would find a way to circumvent the Church and still publish his ideas. He tried. In a book he created an imaginary debate between a scientist and a cleric (named "Simplicio") about the nature of the Universe. Unfortunately for Galileo the imagined debate was so one sided as to be totally transparent. For his crimes against the Church, Galileo was placed under house arrest and excommunicated. The latter was the more serious punishment for it meant that Galileo would die without hope of salvation. (I have recently read that there is some debate as to whether Galileo was in fact excommunicated. Perhaps, this level of punishment did not happen but reflects an urban myth that is widespread and often repeated.)
The lesson taught was quite effective. If the most respected scientist of his day could be silenced, then there would be no point in doing science. Almost no science was done in Catholic Europe for the next 200 years. Italy and Spain which had been the great political and intellectual powers of the Renaissance were quickly surpassed by the rising powers of France, England, and the Netherlands where freer expression of ideas was allowed.
Reading Question: Why was the Church challenged by Galileo's support for the Copernican model that the Earth revolved around the sun?