3.2 Ionian Dawn
Our voyage to the roots of science begins on the shores of the Aegean Sea. Today, the Greek archipelago is mostly known as a destination for tourists. We go there to relax, but many of us also get a strong feeling of being on historic ground by the Mediterranean. The ancient Greeks are associated with wisdom and are said to have laid the foundations of modern civilization, but who were they? Why do we still speak so reverently about them? We know that they were an enterprising, seafaring people that had an intense exchange of goods and culture with other peoples. Those who walked in the ancient docklands of Greece experienced an impressing buzz of foreign languages and new ideas – a cultural draught of rare occurrence.
Maybe it was this diversity that led to a special awakening on the coastlands of Asia Minor a few hundred years before the Common Era (BCE). Here, there were suddenly people who held that everything consisted of tiny building blocks called atoms. A man lived who lived here reasoned that humans must have developed from other animals and thought that life must have occurred spontaneously in the seas. There were people who believed that illnesses were not caused by gods or evil spirits but by natural causes. One of these islanders thought that the earth was a planet orbiting the sun, and not vice versa. Here were people who stated that the world's countries had come about not by intervention by higher powers but by natural, geological processes. Today, we see these ideas as relatively modern but, in reality, they are two and a half millennia old. In the following, which loosely follows the outlines of Farrington [1] and Russell [2], we are going to get to know a few of the persons behind these ideas.
Although the Mesopotamians and Egyptians had developed technology and mathematics to a certain level, what we call the scientific approach first arose in the Greek culture. The older civilizations were agricultural societies with strong central powers. Mathematics and astronomy were used for purely practical purposes, to measure the land and create calendars to facilitate farming. Religion and politics were intimately interwoven and the rulers wanted to be perceived as demi-gods. They had a strong interest in maintaining the prevailing order and religion was an instrument for doing it. The clergy preserved a dogmatic religion. Such societies hardly encourage pioneering thoughts and the questioning of established truths.
The Greek world, by contrast, was not at all as centrally controlled as the older civilizations. The landscape was barren and this made communications difficult. Instead of a central state authority, a large number of autonomous city-states were formed. As people lived from trade there was a strong interest in innovation. The merchants that governed the societies actively supported the technical developments that made business flourish. The cultural exchange also contributed to develop critical thinking. What do you do when you discover that there are two gods who claim to be the ruler of heaven? The Babylonian god Marduk played this role in Mesopotamia, just as Zeus did in Greece. Their differences suggested that they were not the same god with different names. Was one of them just a figment of the human imagination? But if one was, why not both? [3]
Thales counts as the first scientist. That is not just because he acted like an absent-minded scientist: they say that he tripped and fell into a well one evening when he was walking and gazing at the stars. A slave girl is said to have laughed at him for being so concerned with what was in the sky that he did not see what was at his feet. He lived in the sixth century BCE in the town of Miletus on the Aegean coast of what is now Turkey. Besides this anecdote it is his practical and rational attitude towards the world that has given him fame. Both the Egyptian and Babylonian religions imaginatively explained how the world once had arisen from the water. The thought was probably natural, as both countries had literally been conquered from the water. The Babylonians belived that Marduk had bound a rush mat on the water and created the earth on it. Thales also thought that everything had once been water but he left Marduk out of the picture. He held that the world had arisen from the water through a natural process, similar to the silting up of the Nile delta. He describes the world as a disc on the water where we have water on all sides, also above us – where else would the rain come from? [1]
What makes this water hypothesis scientific? The answer lies more in his approach than in his statement. By leaving Marduk out he searches for natural explanations for natural phenomena, and this is what is new and essential. He tells us that things do not happen through the interventions of Zeus or Marduk; it is possible for us humans to understand and explain nature. The water theory may seem bizarre to our modern eyes but is it completely unreasonable? Neither plants nor animals can live without water. Water falls as rain from the skies to the earth and flows via the rivers out to the sea. It can evaporate and become steam, or freeze to ice, so the thought that everything is a circulation of water in different forms seems quite natural. It is not far from the modern view of hydrogen as the origin of all elements. The hydrogen atom is by far the most common one in the universe. When pushed together under unimaginable pressures in the interiors of stars, hydrogen atoms merge into atoms of helium and heavier elements in the nuclear processes that generate the light and heat of the stars. Every element on earth that is heavier than hydrogen – even the atoms in our own bodies – have been spread across the universe by stars that exploded billions of years ago. Our solar system, our earth, and we ourselves are made of this star stuff. Thales’ idea of a single principle behind all matter is certainly not far off.
Thales made trips to Egypt at an early stage; here he learned geometry. He elaborated the Egyptian geometry and, among other things, developed a method for determining the distance to a ship at sea. He realized that it was possible to measure things, even though they were out of reach. We also owe him for another essential development of geometry. The Egyptians already knew that a circle is split into two equal parts by its diameter, but Thales could give a general proof of it. He realized that geometry could be used for more than solving specific problems, it could also be used to obtain general knowledge [1].
He is also famous for predicting a solar eclipse. It is not likely that he had a functioning theory for solar eclipses, so he probably used Babylonian tables and was lucky enough that the eclipse was visible from Greece. At any rate, the eclipse has been dated to 585 BCE and by that we know when he was active [1].
As we have seen, people were mocking Thales for philosophizing instead of engaging in practical things, but he got even with his mockers. One year his grasp of meteorology told him that the olive harvest would be unusually rich and he hired all the olive presses he could lay hands on. At the time of harvest he let them at his own price, making a round sum of money. It was indeed possible to make money on philosophy, he said, but that was not why he engaged in it [2]. In addition to being a good story, this anecdote tells us something important about the times and the society in which Thales lived. You were supposed to engage in things that were practically useful. A couple of hundred years later the times would have changed to the degree that practical relevance was not even desirable. During Thales’ times slavery had not developed enough for practical work to be despised. Scientists, or natural philosophers as they called themselves, worked with practical things. Many of them were sons of sailors, farmers, and weavers. Those who speculated about the laws of nature based their conclusions on everyday practical experience. Craftsmen, engineers and scientists talked to each other and were often the same persons. Among many other things, these Greeks invented the spirit level, the potter's wheel, bronze casting, and central heating [3]. They knew from experience that Nature follows regular patterns that could be discovered and applied to practical purposes. From their perspective it was sensible to seek natural explanations for natural phenomena and take the gods out of the equation.
Before continuing, it may be appropriate to reflect on what this means. If we say that science is born when humans first try to explain the world without referring to deities, does it mean that there is a deep chasm between religion and science? The answer varies between researchers. It is, perhaps, more constructive to reformulate the question: is it possible to be both religious and a successful scientist? The answer is a resolute yes, because there are plenty of examples of such people. If we choose to see science as an approach for solving certain types of problems it is, naturally, possible to use that approach regardless of one's personal philosophy. It is just as possible for a religious person to do research as it is for an atheist to practice yoga. Believing that there is something beyond the observable, some deeper reason behind the regularities in nature, does not necessarily conflict with the wish to investigate and understand these regularities. But if this something really lies beyond the observable, inaccessible to investigation, it also lies beyond the realm of evidence-based knowledge. Whatever view we take to science, it is important to note that gods and miracles are conspicuous by their absence in scientific theories. Not even deeply religious researchers would dream of explaining their data by the intervention of higher powers.
Our next natural philosopher from Miletus, Anaximander, was a friend of Thales. Just like Thales he reflected over practical things and interpreted Nature starting from everyday observations. He did not agree that water was the first principle because he thought that the basic stuff of all matter could not be one of its forms. He chose to call the first principle “the Boundless”. He imagined the sun, moon, and stars to be made from fire and that they were visible through holes moving along the vault of heaven. Anaximander is also the first person known to think that humans had evolved from other animals. He comes to this conclusion by an amazingly simple and elegant line of reasoning. Since our children are born so helpless that they are not able to survive on their own, he says, there would be no humans today if the first of us had come into this world alone. We must have evolved gradually from animals with more autonomous offspring. He thought that life had originated in the seas and that we were descended from fish. Some of the fish had adopted to a life on land and developed into other animals. He supported this statement with fossils and the observation that sharks feed their young. Surely, this idea is what makes Anaximander urge us not to eat fish. When Bertrand Russell describes this idea he jokingly adds: “Whether our brethren of the deep cherish equally delicate sentiments towards us is not recorded” [2].
The last Milesian that we are going to discuss is Anaximenes. According to him, air is the basic element from which everything is formed. This may not seem like a completely fresh idea but his theory contains something new and interesting. The keywords are condensation and rarefaction – words that describe physical processes. He thinks that air becomes heavier and changes form by condensation. By rarefaction it becomes lighter. Anaximenes is said to have gotten the idea while watching water evaporate and condense. He held that condensation was associated with cold and rarefaction with heat. If you have taken a course in thermodynamics you know that this is, in fact, quite the opposite of the truth, but Anaximenes does not expect us to just accept his statements. He shows us how we can convince ourselves by a simple experiment. Breathe against the back of your hand with wide open mouth. Doesn't this rarefied air feel warm? If you instead form your lips to a small opening and press condensed air through it, the feeling on your hand is cold. Of course, Anaximenes did not know what lies behind this effect. Do you? [1]
There are several more natural philosophers in the Ionian tradition that deserve mentioning. This chapter is much too short to do them justice, but we should at least mention a couple of their ideas. Democritus, from the Ionian colony Abdera in northern Greece, said that on the smallest scale of the world there is some irreducible degree of graininess. To describe this he invented the word atom, meaning something that cannot be split. He maintained that there is nothing else in this world than these indivisible atoms and empty space. Therefore, when we cut through an apple the knife must move through the void between the atoms, otherwise it could not be split. He also said that when a cone is cut in half, the two section surfaces will have somewhat different areas due to the tapered shape. By a similar line of reasoning, Democritus concluded that it must be possible to calculate the volume of a cone by adding a number of very thin plates with diminishing diameter from the bottom to the top. By this he came close to inventing infinitesimal calculus, a central mathematical tool that was key to the revolution in physical theory in Newton's time [3].
Finally, for those who think that Nicolaus Copernicus invented the heliocentric theory, in which the earth revolves with the other planets around the sun, it may be interesting to know that a marginal note of the name Aristarchus in one of his manuscripts reveals that he only rediscovered an idea from antiquity. Aristarchus lived in the third century BCE on the island Samos, near Miletus. Although his original manuscript has been lost, Archimedes tells us in his book the Sandreckoner that Aristarchus advocated the heliocentric view. Though it cannot be ruled out that the idea is even older, Aristarchus appears to be the first to give a full and detailed account of this system [2].