When Rebellion Becomes Virtue: How the Scientific Method Came to Be

Carlo Rovelli

Feb 28

Thales is traditionally considered one of the Seven Sages of ancient Greece—more or less historical figures recognized and honored by the Greeks as founders of their thought and institutions. Another of the Seven Sages is Solon, contemporary of Thales and Anaximander, the writer of the first democratic constitution of Athens. According to the traditionally accepted dates, Anaximander is only eleven years younger than his illustrious fellow citizen Thales.

We know nothing of the relationship Thales and Anaximander may have had. We don't even know whether the speculations of thinkers such as Anaximander and Thales were private, or whether there was a school in Miletus along the lines of Plato's Academy and Aristotle's Lyceum. These schools brought together teachers and young students, and their activities included public discussions, lessons, and lectures. Texts from the fifth century BCE tell of public debates among philosophers. Did such debates already exist in Miletus of the sixth century BCE?

As I will discuss later, the sixth century in Greece was the first time in human history that the ability to read and write moved beyond a limited circle of professional scribes and became widespread in large sectors of the general population—essentially the entire aristocracy. Any elementary school pupil today knows that learning to read and write isn't easy. It must have been even more challenging during the first centuries of the use of phonetic alphabets, when writing was far less widespread than today.

Someone needed to teach young Greeks how to write and read. I therefore think it is fair to believe that teachers, tutors, and schools must have existed in the major Greek cities of the time, though I have found no confirmation of this point. The combination of teaching and intellectual research that characterizes the philosophical schools of ancient Athens as well as the universities of today might very well have already been established in the sixth century BCE. In other words, I think it is reasonable to suppose that a true school existed in Miletus.

Whether or not such a school existed, it is nonetheless clear that Anaximander's great theoretical speculations were born of and based on Thales's work. The questions they ponder are identical: the search for the arche, the form of the cosmos, naturalistic explanations for earthquakes and other phenomena, and so forth. Thales's influence is clear even in smaller details. Anaximander's Earth is a disk, just like Thales's. The intellectual relationship between Thales and Anaximander is very close. Thales's reflections nourish and give rise to Anaximander's theories. Thales is Anaximander's teacher—figuratively and probably also literally.

Truth is veiled but may be approached by means of a sustained, almost devotional practice of observation, discussion, and reasoning, where mistakes are always possible.

It is important to consider in depth this close relationship of intellectual paternity between Thales and Anaximander, because it represents, in my view, perhaps the most important keystone of Anaximander's contribution to the history of culture.

The ancient world teemed with masters and their great disciples: Confucius and Mencius, Moses and Joshua and the prophets, Jesus and Paul of Tarsus, the Buddha and Kaundinya. But the relationship between Thales and Anaximander was profoundly different from these. Mencius enriched and studied in depth Confucius's thought but took care never to cast doubt upon his master's affirmations. Paul established the theoretical basis for Christianity, far beyond what is in the Gospels, but never criticized or openly questioned the sayings of Jesus. The prophets deepened the description of Yahweh and of the relationship between him and his people, but they most certainly did not start from an analysis of Moses's errors.

Anaximander did something profoundly new. He immersed himself in Thales's problems, and he embraced Thales's finest insights, way of thinking, and intellectual conquests. But at the same time he undertook a frontal critique of the master's assertions. Thales says the world is made of water. Not true, says Anaximander. Thales says the Earth is floating on water. Not so, says Anaximander.

Thales says earthquakes are attributable to the oscillation of the Earth's disk in the ocean upon which it floats. Not so, says Anaximander: they are due to the Earth's splitting open. And he goes on from there. A still‑perplexed Cicero, centuries later, remarks, "Thales holds that all things are made of water But of this he did not persuade Anaximander, though he was his countryman and companion."

Criticism was not absent from the ancient world—far from it. Take the Bible, for example, in which the religious thought of Babylonia is harshly criticized: Marduk is a "false god," his "diabolical" priests are to be stabbed, and so forth. But between criticism and adherence to a master's teaching there was no middle ground. Even in the generations following Anaximander, the great Pythagorean school—decidedly more archaic than Anaximander in this regard—flourished in reverence to Pythagoras's ideas, which could not be questioned. Ipse dixit ("He himself said") is an expression that referred originally to Pythagoras, meaning that if Pythagoras had made an assertion, it must be true.

Halfway between the absolute reverence of the Pythagoreans for Pythagoras, of Mencius for Confucius, of Paul for Jesus, and the rejection of those who hold different views, Anaximander discovered a third way.

Anaximander's reverence for Thales is manifest, and it is clear that Anaximander leans heavily upon Thales's intellectual accomplishments. Still, he does not hesitate to say that Thales is mistaken about this or that matter, or that it is possible to do better. Neither Mencius nor Paul nor the Pythagoreans understood that this narrow third way is the most extraordinary key for the development of knowledge.

In my view, modern science in its entirety is the result of the discovery of this third way. The very possibility of conceiving it can come only from a sophisticated theory of knowledge, according to which truth is accessible, but only gradually, by means of successive refinements. Truth is veiled but may be approached by means of a sustained, almost devotional practice of observation, discussion, and reasoning, where mistakes are always possible. The practice of Plato's Academy is obviously based on this idea. The same is true for Aristotle and his Lyceum. All of Alexandrian astronomy grows out of the continuous questioning of the assumptions made by earlier masters.

Anaximander was the first to pursue this third way. He was the first thinker able to conceive and put into practice what is now the fundamental methodological credo of modern scientists: make a thorough study of the masters, come to understand their intellectual achievements, and make these achievements their own. Then, on the basis of the knowledge so acquired, identify the errors in the masters' thinking, correct them, and in so doing improve our understanding of the world.

Consider the great scientists of the modern era. Isn't this precisely what they did? Copernicus did not simply awaken one fine day and proclaim that the Sun was at the center of our planetary system. He did not declare that the Ptolemaic system was an illustrious bit of nonsense. If he had, he would never have been able to construct a new, effective mathematical representation of the solar system. No one would have believed him, and the Copernican revolution never would have occurred.

Instead, Copernicus was thunderstruck by the beauty of the knowledge reached by Alexandrian astronomy and summarized in Ptolemy's Almagest, and he immersed himself fully in its study. He appropriated Ptolemy's methods and recognized their efficacy; it was in this way, by exploring the nooks and crannies of Ptolemy's work, that he came to recognize its limits and find ways to radically improve it. Copernicus is very much a son of Ptolemy: his treatise De revolutionibus orbium cœlestium is extremely similar in form and language to Ptolemy's Almagest, so much so that one can almost call De revolutionibus a revised edition of the Almagest.

Ptolemy is unquestionably Copernicus's master, from whom he learns everything that he knows and is useful to him. But to move forward, Copernicus must declare that Ptolemy is mistaken—not just in some detail, but in the most fundamental and seemingly best‑argued assumptions of the Almagest. It is simply not true that, as Ptolemy maintains in an ample and convincing discussion at the beginning of the Almagest, the Earth is immobile and at the center of the universe. Einstein and Newton have precisely the same relationship.

It is the triumphant beginning of scientific thought, the earliest exploration of the possible forms that thinking about the world can take.

And this is not just true for the great scientists: countless scientific articles of today have precisely the same relations to the works preceding them. The strength of scientific thinking derives from the continuous questioning of the hypotheses and results obtained in the past—a questioning that, just the same, takes as its point of departure a profound recognition of the knowledge value contained in these past results.

This is a delicate balance to strike, one that is anything but obvious and natural. In fact, as far as I can see, it is unknown in all of the human speculation that has come down to us from the first millennia of recorded history. This delicate process—following and developing the master's path by criticizing the master—has a precise beginning in the history of human thought: the position that Anaximander assumed vis‑à‑vis his master Thales.

Anaximander's novel approach immediately inspired others. Anaximenes, a few years younger than Anaximander, picked up on the idea and, as we have seen, proposed a modified and much richer theory of the arche, or first cause. Once the path of criticism was open, it could not be closed. Heraclitus, Anaxagoras, Empedocles, Leucippus, Democritus: not one of these thinkers hesitated to speak his mind on the nature of worldly things.

Only to an inattentive observer can this variety of viewpoints and crescendo of reciprocal criticisms seem a growing cacophony. Instead, it is the triumphant beginning of scientific thought, the earliest exploration of the possible forms that thinking about the world can take. It is the start of the road that has given us everything, or nearly everything, that we study and know about the world today.

According to a classic thesis, a scientific revolution comparable to the one in the West did not take place in Chinese civilization—despite the fact that for centuries Chinese civilization was in many ways broadly superior to the West—precisely because the master in Chinese culture was never criticized or questioned. Chinese thinking grew by elaborating on and developing established knowledge, never by questioning it.

This seems to be a reasonable thesis, because one can otherwise barely fathom the fact that Chinese civilization, so overwhelmingly great, never managed to understand that the Earth was round until the Jesuits arrived and told the Chinese so. In China, it seems, there was never an Anaximander.

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