Thales (625 BC? ~ 547 BC? ) was the first natural scientist and philosopher in ancient Greece and the founder of the earliest philosophy school in Greece-Ionian School.

Ionia includes the islands in the central west coast of Asia Minor (now Turkey) and the central Aegean Sea. From 1200 BC to 1000 BC, the Greek tribe Ionians moved here, hence the name. There, the merchant rule replaced the clan aristocratic politics. The activity of businessmen creates favorable conditions for the free development of ideas. Greece has neither specialized clergy nor dogma that must be followed, which is very helpful for separating science and philosophy from religion.

Miletus is a Greek city-state in Asia Minor on the east coast of the Mediterranean Sea, located at the mouth of the Mendels River. It is the transportation hub of the East and the West and the center of handicrafts, navigation and culture. It is easier to absorb the experience and culture accumulated by ancient oriental countries such as Babylon and Egypt than other places in Greece.

Thales was born in Humily, and his family belonged to the noble class of slave owners, so he received a good education from an early age. Thales was a famous philosopher, astronomer, mathematician and scientist in ancient Greece. He enrolled students, established colleges, and established Miletus School. He was not only a representative of spontaneous materialism at that time, but also an early scientific enlightener.

At that time, the whole society was still in a state of ignorance and backwardness, and people could not understand many natural phenomena. However, Thales always wanted to explore the truth of nature. Because he is familiar with astronomy and mathematics, he is an early scientist in human history, so people call him "the father of science".

Thales was an excellent businessman in his early years. He has been to many eastern countries, learned the knowledge of observing solar eclipse and calculating the distance between ships at sea in Babylon, learned the original idea of Phoenician Inge Hiddinsky to explore the composition of everything, and learned the methods and rules of land survey in Egypt. He also went to Mesopotamia, where he studied mathematics and astronomy. Later, he engaged in political and engineering activities, studied mathematics and astronomy, and turned to philosophy in his later years. He dabbled in almost all fields of human thought and activities at that time and gained a high reputation. He was honored as "the head of the seven sages of Greece". In fact, among the seven sages, only he is a learned scholar, and the rest are politicians.

Observe the eclipse

In astronomy, Thales has done a lot of research. He measured and calculated the diameter of the sun. As a result, he announced that the diameter of the sun is about one twentieth of the diameter of the sun road. This figure is very different from the diameter of the sun measured now. After calculation, he learned that sailing in Ursa minor is much more accurate than sailing in Ursa major, and he told those who sailed. By observing and studying the sun, moon and stars, he determined that 365 days is a year. It was remarkable to make such a discovery without any astronomical observation equipment at that time.

In the field of astronomy, people are more interested in his correct explanation of the cause of the solar eclipse and his prediction of an eclipse to prevent a war.

At that time, the kingdom of Medea and the Chaldeans in the lower reaches of the two river basins jointly captured Nineveh, the capital of Assyria, and the territory of Assyria was divided between the two countries. The Medes occupied most of today's Iran, and prepared to continue to expand westward, but they met with stubborn resistance from the Kingdom of Lydia. The two countries fought fiercely in the area along the Haruz River, and they didn't decide the outcome for five consecutive years.

The war brought disaster to the people, and the people were displaced. Thales predicted that there would be a solar eclipse one day in advance. He threatened that God would fight against the world, and one day he would use the solar eclipse as a warning. At that time, nobody believed him. Later, as expected, on May 28th, 585 BC, when the soldiers of the two countries were in hand-to-hand combat, it suddenly became dark, and the day suddenly turned into night. The warring parties were terrified and immediately stopped fighting and made up. Later, the two countries also exchanged marriages.

The end of the war, of course, has political and economic reasons, and the solar eclipse only played a "medicine" role. But people are more concerned about another important issue. How did Thales predict the solar eclipse?

Later generations made various speculations and textual research, and generally believed that the Sharo cycle discovered by the Chaldeans was applied. A Sharon period is equal to 223 moons, that is, 6585.5438+0 124 days or 18 years and1day (if there is a five-year leap year in between, it is 18 years and 10) The sun and the moon run periodically, so does an eclipse. The solar eclipse must happen on a day in the north. If there is a solar eclipse in the north one day, that is, the day after 18 1, the sun and the moon will return to their original positions, so it is very likely that a similar phenomenon will occur.

But after a period of time, the position of the sun and the moon is only roughly the same, so the place where the eclipse can be seen and the scene of the eclipse may change or even not happen at all. Thales probably knew that there was a solar eclipse on May 18, 603 BC, so he was lucky to guess. Of course, there are some other theories about this matter, and there is no unified conclusion.

Measure the height of the pyramid

Thales' epoch-making contribution in mathematics is to put forward the idea of proposition proof. It marks that people's understanding of objective things has risen from experience to theory, which is an unusual leap in the history of mathematics. The significance of introducing logical proof in mathematics lies in: ensuring the correctness of propositions; Reveal the internal relationship between theorems, make mathematics form a strict system and lay the foundation for further development; Make mathematical propositions fully convincing and persuasive.

Proof proposition is the basic spirit of Greek geometry, and Thales is the pioneer of Greek geometry. He evolved Egyptian ground geometry into plane geometry, and discovered some basic geometric theorems, such as "the diameter bisects the circumference", "the base angles of isosceles triangles are equal", "two straight lines intersect and their top angles are equal", "the circumference angles of semicircles are right angles" and "the corresponding sides of similar triangles are proportional", and applied geometric knowledge to practice.

It is said that no one has been able to accurately measure the height of the Great Pyramid of Egypt for more than 1000 years after its completion. Many people made a lot of efforts, but they didn't succeed.

One spring, Thales came to Egypt. People want to test his ability and ask him if he can solve the problem. Thales confidently agreed, but on one condition-Pharaoh must be present. The next day, Pharaoh arrived as promised, and many onlookers gathered around the pyramid. Before Thales came to the pyramid, the sun cast his shadow on the ground. Every once in a while, he lets others measure the length of his shadow. When the measured value is completely consistent with his height, he immediately made a mark on the projection of the Great Pyramid on the ground, and then measured the distance from the bottom of the Pyramid to the projection spire. In this way, he quoted the exact height of the pyramid. At the request of Lao Wang, he explained how to push the principle from "shadow length equals body length" to "tower shadow equals tower height". Which is today's similar triangles theorem.

Everything is aquatic, and everything has spirit.

Thales' philosophy can be summarized in one sentence: "Everything is aquatic, and everything belongs to water". He thinks that the world is water. The seven sages of ancient Greece each had a particularly famous motto. His motto was: "Water is the best".

Thales learned to observe floods from the Egyptians. He has a lot of experience. He carefully read the records of the annual flood and ebb of the Nile and witnessed the phenomenon of the river retreating. He found that every time the flood receded, not only fertile silt was left, but also countless tiny germs and larvae were left in the silt. He combined this phenomenon with the primitive Egyptian myth that God created the universe and came to the conclusion that everything is made of water.

For Thales, water was the first basic element in the world. Egyptian priests claimed that the earth rose from the bottom of the sea, while Thales thought that the earth was floating on the water.

Thales also has a very important point of view that "everything is animistic". According to this theory, even stones are creatures with souls. Thales repeatedly emphasized to Pythagoras, the antithesis of his philosophy, that the whole universe is alive, and it is the soul that makes everything full of vitality. This statement was very popular at that time.

Thales once experimented with magnets and amber and found that these two objects were attractive to other objects, so he thought they had vitality inside, but this life was invisible to the naked eye. From this, Thales concluded that any stone looks cold, hard and lifeless, but it also contains a soul. Until 300 BC, the Stoic philosophers used Thales' experiment to prove that everything in the world was attracted by life.

Legends and anecdotes

1. Thales is a successful businessman. His business life has made him understand the local customs and broadened his horizons.

He used mules to transport salt. Once, a mule slipped into a stream, and part of the salt dissolved, which lightened a lot of burdens. So every time the mule crosses the stream, it rolls. In order to change the bad habit of this animal, Thales changed it to carry a sponge. After sucking water, its weight doubled, and the mule never dared to be lazy again.

There is also a story about doing business. Thales used all kinds of knowledge to foresee the bumper harvest of olives, so he monopolized the oil presses in this area, and things really developed in the direction he expected. He rented the oil press at his own price and gained great wealth.

But he doesn't want to be a rich man, but he wants to answer some people's sarcasm: if you are smart enough, why don't you get rich? He proved by facts that it is more difficult to study astronomy than to get rich.

According to records, Thales once looked up at the astronomical phenomena and accidentally fell into the well. His maid pulled him out and said, "How can you see the land under your feet if you only look up at the sky?" Thales was surprised at such philosophical words.

Thales' humor is not very philosophical. He is interested in "how to live a philosophical and upright life?" The answer is: "Don't do what you hate others to do." This is similar to China's "Don't do to others what you don't want others to do to you" (The Analects of Confucius).

Someone asked, "What is the strangest thing you have ever seen?" His answer is: "Long live the tyrant."

Another question: "What do you want from an astronomical discovery?" The answer is: "when you tell others, don't say it's your discovery, say it's mine." This is my highest reward. "

Plutarch records that Solon visited Thales in Miletus and asked him why he never got married. Thales didn't answer at the time. A few days later, a stranger came to Solon and said that he had been to Athens the day before. Solon asked him about the news there. The man said: the funeral of a young man caused a sensation in the whole city. His father was a powerful man, and his son was not at home when he died, because he had already gone out to travel.

Solon was frightened to disgrace and hurriedly inquired about the young man's name. The man said he didn't remember clearly, but he looked smart and upright. Solon was about to guess that something had happened to his son when Thales smiled and advised, that's why I refused to get married and have children! Even a strong man like you can't stand such a thing. But the news is fictional, don't mind too much.

In the early days of human civilization, there were always some wise men who made achievements in many fields, trying to explain the mysterious nature and teach people who were still in a semi-ignorant state. Aristotle is one of them. In 384 BC, Aristotle was born in northern Greece. His father is a court doctor in the kingdom of Macedonia and has close ties with the Macedonian royal family. It is said that Aristotle was influenced by his family and studied medicine in his early years. 18 years old, came to Athens, the cultural capital of Europe at that time, and studied philosophy under the great philosopher Plato. Plato appreciated Aristotle's talent very much, and Aristotle did learn the wisdom of life from Plato. However, a genius will never completely live in the shadow of another genius. Aristotle and Plato later had philosophical differences. He declared that "Plato is valuable, but truth is more valuable" and finally parted ways with Plato. As a result, when Plato died, Aristotle, the best student, failed to become the leader of his college.

With Plato's burial, the second person who had a great influence on Aristotle appeared, and he was Aristotle's student Alexander. After Aristotle left Athens, he was called by King Philip of Macedonia to teach 13-year-old Prince Alexander. This Alexander is the Alexander the Great who conquered Greece, Egypt in the south and Persia in the east, and led Macedonian soldiers to the Indus Valley. Later generations have always been puzzled. It is strange that a wise philosopher like Aristotle should educate a militaristic military talent instead of a well-educated man who knows books and manners. It seems that Alexander's nature is to kill on the battlefield. Even the best philosopher can't reduce his desire to conquer the world. Education is not everything.

Although the students didn't have the theory that the teacher was brilliant, they let the teacher return to Athens beautifully. After Alexander succeeded to the throne and conquered the Greek city-state, Aristotle returned to Athens, where he established his own school of philosophy-Minstrel. Aristotle likes to teach students all kinds of knowledge while walking in his own school, or discuss problems with visitors. Feeling, exploring and learning from nature is not hard work, but fun. However, in our present campus, dozens of students are locked in dirty classrooms, studying hard day after day and year after year, unable to study happily, not as good as the students more than 2,000 years ago.

At this time, Aristotle was 50 years old. He finally stopped wandering and began to write books. As a tireless writer, Aristotle claimed to have written 150 books, but only about 30 books have been handed down. Even if it is only a small part of his works, we can still see that he involves many fields, such as astronomy, meteorology, philosophy and biology. He was the king of life at that time, and he described the marine life such as octopus, squid and crustacean very accurately. Later generations thought that he was definitely not hearsay, but personally obtained evidence and obtained first-hand information. He described the development process of chicken embryo; He correctly divided whales, dolphins and fish into different kinds; He also described the gastric peristalsis of ruminants and studied the social structure of bees. He also noticed that some sharks gave birth to young sharks directly, which has always been considered "absurd", but Aristotle was finally proved to be right by science.

As an explorer in an unknown field, Aristotle also made many mistakes. For example, he thinks that the sex of a baby depends on the strength of the father. A strong father will have a boy, and a weak father will have a girl. He also believes that some lower organisms are "spontaneous reproduction", that is, they can be born directly from inorganic nature. In the eyes of modern people with basic science education, Aristotle's view is very ridiculous. However, the wise Aristotle had long expected such a scene. He said: "I haven't found any ready-made foundation, and there is no model to copy. I'm taking the first step, so it's just a small step. My readers will understand what I have achieved and forgive what I left to others to complete. " The philosopher knows that his views must be right and wrong, and asks future generations to forgive his unfinished business and his mistakes.

Did future generations forgive him? Why forgive him? Later generations simply deified him. For more than 1000 years after him, Aristotle's thoughts ruled the European scientific community like an emperor. When two scientists are arguing, as long as one of them says, "Aristotle thought so too," the other scientist immediately shuts up. Aristotle's name stands in front of the road in many fields, waiting for people to surpass it. He pointed out the right direction on many roads and the wrong direction on some roads, but later generations followed suit for more than 1000 years. Is this the luck or misfortune of science?

Aristotle didn't know these things. After the news that his student Alexander the Great died in the expedition reached Athens, he immediately fell out of favor and was surrounded by people who opposed him. Socrates, his teacher's teacher, was executed after being tried by "democracy" in Athens. Lessons from the past convinced Aristotle that it was necessary to "prevent the Athenians from committing anti-philosophical crimes again". So Aristotle ran away and his scientific life ended here in 323 BC. A year later, Aristotle's tortuous life came to an end.