Our ancestors by sacrificing in accordance with the tablets of Solon [laws instituted in the early sixth century] have handed down to us a city superior in greatness and prosperity to any other in Greece so that it behooves us to perform the same sacrifices as they did if for no other reason than that of the success which has resulted from these rites. 5
So, Greek religion acted as mediator of political and social tensions. Transitions could be effected through the use of ritual and difficult decisions made with the help of oracles. Even so, political life was not easy, and in the seventh and sixth centuries in particular there were continual clashes between the old aristocratic elites and the newly wealthy, who had made their money through trade, and the rising peasant classes, increasingly conscious of their own cohesion and power. At the very worst a city would explode into civil war. Thucydides describes one case in 427 in Corfu, which saw a vicious spiral of terror and counter-terror between the ruling classes and “democrats.” In the resultant complete breakdown of order, where, as Thucydides puts it, “fanatical enthusiasm was the mark of a ‘real man,’ ” fathers killed sons, temples were violated by the massacre of those sheltering in them and many committed suicide rather than wait to be killed. “As for the citizens who held moderate views, they were destroyed by both the extreme parties, either for not taking part in the struggle or in envy at the possibility that they might survive.”6 The most sophisticated resolution of conflicts such as these was to be made in fifth-century Athens, where all male citizens came to share in government equally, in the Assembly, as jurors in the law courts and, for those aged over thirty, as administrators. Athenian democracy lasted some 140 years and, despite its exclusion of women and slaves, remains a remarkable political innovation.
It was in this resolution of internal conflicts that a remarkable intellectual development took place. It seems to have been based in an optimistic belief that there were forces that tended to good order.7 One finds such a feeling in the early sixth century B.C. in the verses of the Athenian statesman Solon, who had been charged with resolving a political crisis caused by the economic and social exploitation of a debt-ridden peasantry by the landed aristocracy. He proved to be a pragmatic statesman— it is human beings themselves, not the gods, who must bring peace and good order (the Greek word used is eunomie) to their cities. However, eunomie (who is personified as a daughter of Zeus) is seen as a force in her own right, even if one who works alongside mankind. In Solon’s own words:
Eunomie makes all things well ordered and fitted
and often puts chains on the unjust;
she smooths the rough, puts an end to excess, blinds insolence,
withers the flowers of unrighteousness,
straightens crooked judgements and softens deeds of arrogance,
puts an end to works of faction
and to the anger of painful strife, under her
all men’s actions are fitting and wise.8
In other words, the political world tends towards stability under the auspices of divine forces. The work of the politician lies in shifting the city’s affairs into their natural groove of harmony, and he will be sustained by eunomie in achieving this (“under her all men’s actions are fitting and wise”). However, remarkably and apparently uniquely to the Greek world, a further intellectual leap appears to have taken place; it was appreciated that if the city tended to good order, perhaps the universe, the cosmos, did as well. The natural world was seen to change according to rhythms, of the seasons but also of the movements of the stars, rhythms that appeared to persist in spite of the fragmented and unpredictable nature of everyday life. Only a few years later than Solon, in 585 B.C. in the Ionian city of Miletus on the coast of Asia Minor, the philosopher-scientist Thales is said to have predicted an eclipse of the sun (the eclipse did indeed take place and was independently recorded by the historian Herodotus). For Aristotle, writing some 200 years later, this was truly the moment when Greek philosophy began. An underlying order to the cosmos had been observed, and its movements were assumed to be so regular that future events could be predicted from empirical observations gathered over time.
This single instance was not revolutionary in itself—after all, the Egyptians had been able to work out a calendar based on the regular phases of the moon as early as 2800 B.C. Where Thales and his associates in Miletus went further was to speculate on why the world was as it was. They began to ask major questions. What was the cosmos made of, and why did it move in the way it did? Thales himself suggested that the world may have originated in a single substance, water, and that it rested on a base of water. He was challenged by another Milesian, Anaximander. What then did the water rest on? Anaximander suggested that the apparent stability of the world arose because it was at the centre of equally powerful forces—the Boundless, he called them—that surrounded the world on all sides and from which it had been formed. Just as a city would tend towards harmony, so would the cosmos be held in balance by these surrounding forces. Another Milesian, Anaximenes, suggested that everything came from air. If steam could be condensed into water and water could be frozen into ice, it followed that a single substance could change form dramatically, and perhaps air could be condensed into solid forms. These speculations were bound to be primitive, but they did represent a new way of thinking and, moreover, one in which each thinker was able to use observation and reason to challenge his rivals. So within 150 years of Odysseus’ swim to Phaeacia, rational decision-making had been transformed into something much more sophisticated and universal, what we might call science. Thinking about how the predictable rhythms of the natural world related to the observed chaos of the actual world presented, of course, a daunting challenge. But it was faced as early as 500 B.C. The brilliant Heraclitus (from the city of Ephesus, close to Miletus) believed that the underlying order (the word he used was logos, which will reappear many times in this book) was sustained by continual tensions between different forces. The harmonious city, said Heraclitus, is not one in which everyone lives in peace but one among whose citizens there is constant activity and debate. “Justice,” said Heraclitus, “is strife.” 9
Heraclitus’ insight that reasoned thought is born within the tensions of the city state is supported by modern research. Geoffrey Lloyd, who has carried out intensive explorations of the background to Greek scientific thinking, traces the origins of a systematic use of reason (without which empirical observations cannot be related to each other) to the intense political debates that raged within the Greek cities. If two factions wished to find a “just” solution to a problem without tearing apart their own city, then at some point there was likely to be a consideration of what was meant by “justice.” There was an incentive to go back to first principles and attempt to define an agreed basis, some kind of axiomatic statement, from which to begin the arguments that could only take place according to rational principles if agreement was to be maintained between the opposing parties. Lloyd argues that this process can be discerned within the fragments of political debate that survive, and, crucially, it was also applied to the study of the natural world. The terminology used supports this. Lloyd shows how a word such as “witness,” as used in the law courts, was the root of the word for “evidence” in scientific discourse, and how the term used for cross-examination of witnesses was adopted to describe the testing of an idea or hypothesis. He also argues that within the city the ability to argue persuasively conferred status, and that this status could be transferred into other areas of intellectual activity.10
So began the great adventure of the Greek speculative tradition. It was not a coherent process. Martin West writes:
Early Greek philosophy was not a single vessel which a succession of pilots briefly commanded and tried to steer towards an agreed destination, one tacking one way, the next altering course in the light of its own perceptions. It was more like a flotilla of small craft whose navigators did not start from the same point or at the same time, nor all aim for the same goal; some went in groups, some
were influenced by the movements of others, some travelled out of sight of each other.11
One important development was the distinguishing and segregation of the process of reasoning itself. The earliest surviving sustained piece of Greek philosophical reasoning comes from the first half of the fifth century, from one Parmenides from the Greek city of Elea in southern Italy. Parmenides attempts to grasp the nature of the cosmos through the use of rational thought alone (in other words, without any reliance on empirical observation). He realizes that no argument can begin unless some initial assumptions are made. His “It is and it is impossible for it not to be” is the assumption with which he starts. As Parmenides, through a goddess who is given the role of developing the argument, works towards his conclusion that all material is a single undifferentiated and unchanging mass, many controversies arise, not least because of the problems in using verbs such as “to be” in a completely new context, that of philosophical reasoning. But what Parmenides did achieve was to show that once basic assumptions and axioms have been agreed upon, reason can make its independent way to a conclusion. However, his conclusion, that it is rationally impossible to conceive of materials undergoing change, seems absurd, and it raises for the first time the question of what happens when observation and reason contradict each other.
A follower of Parmenides, Zeno (who also came from Elea), highlighted this issue in his famous paradoxes. An arrow which has been shot cannot move, says Zeno. How can this possibly be? Because, answers Zeno, it is always at a place equal to itself, and if so it must be at rest in that place. So, as it is always at a place equal to itself, it must always be at rest. In Zeno’s most famous paradox, Achilles, the fastest man on foot, will never catch up with a tortoise, because when he has reached the place where the tortoise was, the tortoise will have moved on, and when he has reached the place to which the tortoise has progressed, it will have moved on yet further. While reason can suggest that Achilles will never catch the tortoise, experience tells us that he will and that he will soon outstrip it. Observation and reason may be in conflict, and the result is a conundrum. The fact that the Greeks recognized such problems yet were not daunted by them is a measure of their growing intellectual confidence.
The next step, then, in this parade of intellectual innovation is to try to isolate the circumstances in which rational argument can be used to achieve certainty without being challenged by what is actually observed by our senses. Here the achievement of Aristotle was outstanding. One of Aristotle’s many contributions to the definition of certainty was the introduction of the syllogism, a means by which the validity of a logical argument can be assessed.12 A syllogism is, in Aristotle’s own words, “an argument in which certain things being assumed [the premises], something different from the things assumed [the conclusion] follows from necessity by the fact that they hold.” What kinds of things can be “assumed”? The famous examples, although not used by Aristotle himself, are “All men are mortal” and “Socrates is a man.” Both premises seem fully tenable. No one has come up with an example of a man who has not died; it is part of the condition of being human. Similarly, anyone who met Socrates would have agreed that he was a man. From these two assumptions could be drawn the conclusion: “Therefore Socrates is mortal.” Aristotle went further, replacing the subjects of the assumptions with letters, so that it follows if all As are B, and C is an A, then C is B. One can substitute any suitable premises to create a valid conclusion. Aristotle goes on to explore the cases where the logic does not work. “A dog has four feet” and “A cat has four feet” are both reasonable assumptions to make from one’s experience of dogs and cats in everyday life, but it does not follow that a cat is a dog, and the student in logic has to work out why this is so. “All fish are silver; a goldfish is a fish; therefore a goldfish is silver” cannot be sustained because the example of a living goldfish would itself show that the premise that “All fish are silver” is not true.
Aristotle’s syllogisms can take us only so far; their premises have to be empirically correct and relate to each other in such a way that a conclusion can be drawn from their comparison. They provide the basis for deductive argument, an argument in which a specific piece of knowledge can be drawn from knowledge already given. The development of the use of deductive proof was perhaps the greatest of the Greeks’ intellectual achievements. Deductive argument had, in fact, already been used in mathematics by the Greeks before Aristotle systematized it. In an astonishing breach of conventional thinking, the Greeks conceived of abstract geometrical models from which theorems could be drawn. While the Babylonians knew that in any actual right-angled triangle the square of the hypotenuse equals the sum of the squares of the other two sides, Pythagoras’ theorem generalizes to show that this must be true in any conceivable right-angled triangle, a major development both mathematically and philosophically. A deductive proof in geometry needs to begin with some incontrovertible statements, or postulates as the mathematician Euclid (writing c. 300 B.C.) named them. Euclid’s postulates included the assertion that it is possible to draw a straight line from any point to any other point and that all right angles are equal to each other. His famous fifth postulate stipulated the conditions under which two straight lines will meet at some indefinite point. (It was the only one recognized as unprovable even in his own day and eventually succumbed to the analysis of mathematicians in the nineteenth century.) Euclid also recognized what he termed “common notions,” truths that are applicable to all sciences, not merely mathematics, such as “If equals be added to equals, the wholes are equal.” These postulates and “common notions” might seem self-evident, but in his Elements, one of the outstanding textbooks in history, Euclid was able to draw no less than 467 proofs from ten of them, while a later mathematician, Apollonius of Perga, was to show 487 in his Conic Sections. As Robert Osserman has put it in his Poetry of the Universe:
In a world full of irrational beliefs and shaky speculations, the statements found in The Elements were proven true beyond a shadow of a doubt . . . The astonishing fact is that after two thousand years, nobody has ever found an actual “mistake” in The Elements— that is to say a statement that did not follow logically from the given assumptions.13
Later mathematicians, such as the great Archimedes (see below, p. 43), were to develop new branches and areas of mathematics from these foundations.
Dealing with the natural world is a much more complex business. It seems to be in a constant state of change—the weather changes, plants grow, wars happen, men die. As Heraclitus had observed, all is in a process of flux. Yet if an underlying order can be assumed and isolated, then some progress can be made. Such progress assumes that the gods do not disturb the workings of the world on pure whim (as they do, for instance, in prescientific thinking—if the gods can intervene to change the course of the stars or the boiling point of water at random, for instance, then nothing is predictable). The next task is to isolate cause and effect, the forces that cause things to happen in a predictable way. One finds an excellent example of this process in the Histories of Herodotus (probably written in the 430s B.C.). Herodotus starts his famous survey of Egypt (book 2) with speculation on the causes of the annual Nile floods. He considers three explanations which, he tells us, others have put forward. One is that the summer winds force back the natural flow of the water, and as they die down a larger volume of water is released in compensation. This cannot be true, he notes, because the floods occur even in years when the winds do not blow. Moreover, no other rivers show this phenomenon. The second explanation is that the Nile flows from an ocean that surrounds the earth. This is not a rational explanation, says Herodotus; it can only be legend. Probably Homer or some other poet (he says somewhat scornfully) introduced the idea. The third explanation is that it is melting snows that cause the floods, but surely, says Herodotus, the further south you go the hotter it gets, as the black skins of the “natives” suggest. Snow would never fall in such regions. He goes on to provide an elaborat
e explanation of his own, based on the sun causing the Nile to evaporate just at a time when rainfall is low, so creating an artificially low volume of water in comparison to which the normal flow is a “flood.” He misses the true cause, the heavy summer rains that run down from the mountains of Ethiopia, but even if he reaches the wrong answer, Herodotus is aware of and consciously rejects mythological explanations. He uses observation and reason to discard some explanations and formulate others. Here is the process of “scientific” thinking at work.14
One of the most famous early “scientific” texts relates to epilepsy. Epilepsy had traditionally been known as “the sacred disease,” because its sudden onset and violent nature suggested an act of the gods, yet in a text attributed to Hippocrates, probably from the early fourth century B.C., the writer states:
I do not believe that the so-called “Sacred Disease” is any more divine or sacred than any other diseases. It has its own specific nature and cause; but because it is completely different from other diseases men through their inexperience and wonder at its peculiar symptoms have believed it to be of divine origin . . . [yet] it has the same nature as other diseases and a similar cause. It is also no less curable than other diseases unless by long lapse of time it is so ingrained that it is more powerful than the drugs that are applied. Like other diseases it is hereditary . . . The brain is the cause of the condition as it is of other most serious diseases...15
Here we have not only the specific rejection of the divine as a cause but a sophisticated attempt based on observation to say something about the real nature of epilepsy, its causes and its cures. It should be stressed, however, that the rejection of divine intervention did not mean a rejection of the gods themselves. The famous Hippocratic oath, which probably dates from the beginning of the fourth century, requires the physician to swear by the gods Apollo, Asclepius and Asclepius’ two daughters, Hygeia and Panacea. It was rather that the sphere of activity of the gods was diminished and there was greater reluctance, at least among intellectuals, to see natural events as caused by them. Alternatively, they could be seen as the forces that set in motion the regularity with which the natural world operates.
The Closing of the Western Mind: The Rise of Faith and the Fall of Reason Page 3