Ancient Greek philosophy

The adoption of iron and alphabet provides new opportunities for human society, especially those who engage in maritime trade, or those who directly entered the iron age from barbarism, thus getting rid of the cultural tradition of the Bronze Age to a certain extent and making full use of these opportunities. Lasquin and Phoenicians who migrated westward from Asia Minor and the Middle East to Italy and North Africa were both navigators, but they kept some traditions of the Bronze Age in their homeland, such as observing the livers of animals to make sacrifices to gods for divination. Romans and Hebrews entered civilization in the Iron Age, but they mainly cultivated land, not navigators, so they made no significant contribution to science.

Only the Greeks directly entered the civilization of the Iron Age from the barbaric age, and they were a nation engaged in navigation from the beginning. Greeks have a sense of traveler or geometry about space, which is lacking in the agricultural society that settled in the pre-Greek era and the agricultural society that was later isolated from Greek thought (such as the civilization of China). The ancient Greeks also had knowledge about travelers of different cultures and traditions, which enabled them to absorb the truly valuable parts from each culture and tradition without sticking to any particular culture and tradition.

The first natural philosopher in Greece was Thales of Miletus (about 625-545 BC); The achievements that people owe to him illustrate these situations. It is said that he once went to Egypt on business, gained knowledge of geometry in Egypt, and went to Mesopotamia to study astronomy there. According to legend, he once predicted a solar eclipse, although this prediction was impossible at that time; It is also said that he once proved that the diameter of the circumference divides the circumference into two, which is a well-known fact. Thales undoubtedly heard the legends about creation in Babylon and Egypt, and in these two legends, water was in a primitive chaotic state, because he assumed that everything was produced by water. He imagined that the earth was a cylinder or a disk floating on the water, and the sky was also water, so it rained.

In the philosophy of Thales and other Ionian Greeks, nature became less personified than in the world view of the Bronze Age. Greek philosophers before Socrates tend to remove God from nature and assume that celestial bodies are solid objects, not powerful humanized things. To some extent, their contemporaries, Kbe in Hebrew, Zoroaster in Persia and Sakyamuni in India, also separated God from nature. These religious reformers narrowed down the tasks assigned to God in the Bronze Age. His duty is to rain and ensure a bumper harvest, and to show that God is mainly concerned with people's spiritual happiness. Therefore, old gods has become more abstract and spiritual, just as the Greek world has become more impersonal and materialistic.

Babylonians and Egyptians used to think that water, and later air and land were the main elements of the world. Anaximander, the second militarist philosopher (about 6 1 1-547 BC), added the fourth element fire and assumed that primitive matter existed before the elements were formed. After the four elements are formed by this primitive substance, they are divided into four layers according to the order of soil, water, gas and fire. Fire makes water evaporate, producing land, and water vapor rises to surround the fire with circular tubular clouds. What people see in their eyes is like a celestial body, which is the hole of these pipes, so that we can see the fire inside from the hole. The diameter of the tube containing the sun is about 27 times that of the earth, and the diameter of the tube containing the moon is 18 times that of the earth. The earth itself is a cylinder, and its height is about three times its width. The sky surrounds the earth layer by layer, "like bark", while the earth sits firmly in the center, "because it is the same distance from everything" Anaximander thinks that living things are produced by water, while advanced animals evolved from lower animals: "Living things are produced by wet elements evaporated by the sun. Man is the same as another animal, and that is fish. "

Anaximenes (about 550-475 BC), the third Miletus philosopher, believed that gas or air was primitive substance and described that other elements were composed of air. When the air becomes thin, it becomes fire. His argument is that air is hot when it comes out of the mouth, but it feels cold when it comes out under pressure. Similarly, through the process of condensation, gas first becomes water and then becomes soil. The difference between these elements is only the result of quantitative change, and the elements are only air condensation or thinning to varying degrees.

The metaphors used by these Miletus philosophers to explain the structure and changes of the world are very different from the creation stories used by Babylonians and Egyptians to explain the structure and changes of the world. The Greeks never thought that organism reproduction or imperative spells were the origin of creating the world, but used technological process as a metaphor. Anaximenes compared the formation process of elements to the process of making felt: "Clouds are compressed by air like making felt. If clouds are further compressed, they become water." Anaximander believes that the formation of the world is a cooking process, and fire is an active factor. Fire is listed as one of the four elements, which shows that these philosophers are interested in technology, because using fire is not what they are good at, but what chefs, metallurgists and potters are good at.

Philosophers before Socrates, like Babylonians, used metaphors of aggression and revenge. Babylonians once sent Flint out of Mars, explaining that it was God's punishment for Flint because it invaded them. Similarly, anaximander regards the change of elements and the formation of elements on objects as a process of aggression and revenge: "When things become that form, they disappear, which is also reasonable, because they compensate and satisfy each other in time order." So cold in winter offended heat, and heat retaliated against cold in summer. Everything will disappear, because when something is born, it offends the existing things, so it must be retaliated. There is a principle of revenge in the natural process, which is a metaphor derived from the customs and habits of human society, because revenge is often used before due legal procedures appear. For this reason, the ancient meaning of the word "aitia" in Greek is "sin". This view was finally considered that nature, like human society, was replaced by the view of legal rule.

Heraclitus of Eiffel (about 550-475 BC) widely used the idea of revenge as a principle to explain the world order. He imagined that such a principle dominated the movement of celestial bodies, the corresponding changes of elements and all the processes in nature. Revenge is a constantly changing principle, and Heraclitus pays attention to the changing process of nature, not the structural characteristics of the world. He believes that fire is the origin and image of all things, and the burning flame symbolizes the universal and endless phenomena and changes in nature. Fire is the foundation of all things, so behind all qualitative changes in nature, there is a continuity of quantity between objects, which is dominated by a principle similar to that used in commercial transactions: "Everything turns into fire and cremates into everything, just as goods turn into gold and gold turns into goods."

This commercial metaphor, especially the emphasis on the quantitative characteristics of natural phenomena, also contributes to the formation of Pythagoras school and atomic school system; These schools all believe that the units of numbers or discrete particles are the basis of the universe, just as the quantitative units of coins provide the basis for business. It is said that the Pythagorean philosopher Philolaus (about 480-400 BC) once said, "You can see that the power of numbers plays a role not only in ghosts and gods, but also in all human behaviors and thoughts, in all crafts and music."

Pythagoras (about 582-500 BC) was born in Samos Island, but he left his hometown and went to Claughton, a Greek territory in southern Italy, where he established a secret society dedicated to mathematical research and religious cultivation. This association has male and female members with equal status. All property belongs to the public. Even their mathematical discoveries are regarded as the public property of the association, but kept secret from the outside world. But Pythagoras split into scientism and religion in the 5th century BC, and the scientism represented by Philo Routh of Linton published Pythagoras' views.

Pythagoras believes that number provides a conceptual model for the universe, and quantity and shape determine the shape of all natural objects. At first, they thought that numbers were geometric, material and arithmetic entities formed by unit points or particles. They arrange such unit points on the corners of various geometric figures, which are called triangular numbers, square numbers and so on. In this way, in Pythagoras' view, numbers not only have quantity, but also have geometric shapes. It is in this sense that they understand numbers as the forms and images of natural objects.

In mathematics, Pythagoras found their views contradictory. The geometric theorem named after Pythagoras shows that the sum of squares of two sides of a right triangle is equal to the square of the hypotenuse. On some of these triangles, the length of the hypotenuse cannot be measured. One of the simplest examples is an isosceles right triangle, whose hypotenuse is twice the length of one of the other two sides. Pythagoras showed that they could not be represented by integers or several integers. Because they adopted the atomic view of quantity and number, they found themselves facing a difficult situation. There are two solutions to this dilemma, one is mathematical and the other is physical. To solve it mathematically, we must basically give up arithmetic and focus on geometry, because even if we can't express it with a certain number of unit points, we can express it with a fixed length. By solving problems by physical means, atomists give up the numerical properties of Pythagoras' unit point and study the physical properties of unit point instead.

Pythagoras believes that the universe can be divided into three parts in the order of nobility and perfection. These three parts are Uranos, or the lower part of the earth and the moon; The universe, or the boundary part with stars as the boundary; Olympos, or the residence of the gods. The earth, celestial bodies and the whole universe are all a sphere, because the sphere is the most perfect of all geometric solids. All kinds of objects in the universe do uniform circular motion, because the circle is a perfect geometric figure, and the slower the celestial body moves, the more noble and sacred its position becomes. The hypothesis that celestial bodies must move in a uniform circular motion has always controlled the principle of astronomical science until modern times, which was explained as follows for the later Greek astronomer, Jimeneus of Rhodes (about 70 BC):

"The Pythagorean school was the first person to study these problems. They put forward the hypothesis that the sun, the moon and the planets move in a uniform circle. They think that taking sacred and eternal celestial bodies as an example, it is not allowed to imagine that their movements are fast or slow, or even stop at the so-called planetary station. Even within the scope of human activities, such irregularities do not conform to the calm behavior of an upper-class person. Even if some rigid requirements in life often force people to be in a hurry or hesitate sometimes, we can't imagine that the immortal nature of stars will make them encounter such opportunities. To this end, they explain the problem of cosmic phenomena according to the assumption of uniform circular motion. "

Pythagoras believes that the sun, the moon and the planets should circle the sky from west to east in their respective periods and rotate in opposite directions every 24 hours, which is unsatisfactory from an aesthetic point of view. In order to overcome this unsatisfactory phenomenon and satisfy the principle that the base star runs faster than your star, Philo Routh imagined that the earth would go around the fire group in the center of the universe along the orbit from west to east every day. It always faces the central fire with the same side when moving, just as the moon always faces the earth with the same side. Greece is on the side of the earth facing away from the central fire. But even on the side facing the fire, the fire is still invisible, because there is something called "anti-earth" between the earth and the fire, which runs as fast as the earth and always covers the fire.

Pythagoras' hypothesis that the earth revolves around the fireball every day shows that the sky moves on the surface of the earth on Sunday, indicating that all the moving celestial bodies in the universe revolve around the central fireball from west to east in the same direction, and their turnover period increases or decreases according to the nobility of the celestial bodies. The earth is the meanest celestial body in the universe, so it revolves around the fire once a day, the moon revolves around the fire once a month, the sun revolves around the fire once a year, the cycle of the planets is longer, and those stars are stationary. This view requires that the stars should change their mutual visual positions between dusk and dawn when the earth runs a fixed journey every day, unless the distance between the stars and the earth is infinite. Pythagoras believes that the distance between the celestial body and the central fire group is directly proportional to the interval between scales, which makes the distance between the star and the earth within a limited range. However, the parallax of stars, that is, the movement of stars relative to the viewing angle, was not observed at that time, so the original Pythagorean world system had to be revised. There is no parallax between stars, which means that the Sunday orbit of the earth around the central fire group is much smaller than previously thought. According to the above meaning, two Pythagorean scholars, Seitas and Ekfentas, were both Syracuse ancients. They all assume that the earth is at the center of the universe and rotates on its axis every day. This view explains the phenomenon that there is no stellar parallax and maintains the main outline of Pythagoras theory.

The Pythagorean school in southern Italy also has its biologists and anatomists. Alker Alcmaeon of Claughton was the first to be famous, and his activity period was about the fifth century BC. It is said that he once discovered the optic nerve connecting the eyes and the brain and the Euclidean tube connecting the ears and the mouth through anatomy. Alkell Mayang believes that man and the whole universe are based on the same design, and man is the epitome of the whole macro world. This view has become a fixed part of Pythagoras' theory.

Another philosopher influenced by Pythagoras was empedocles of Agrigentan, Sicily (about 500-430 BC). Empedocles thinks that everything is the cooperation of four elements in different proportions, just as all colors are mixed by painters with four different amounts of pigments. The power to combine and separate elements is love and hate, both of which are contained in the inherent nature of elements. Water and soil are unified, because they are both cold, but at the same time they are opposite, because water is wet and soil is dry. Similarly, air and fire are hot, but one is wet and the other is dry. Also, water and air, soil and fire all have the same properties at the same time, but they also have opposite properties.

Empedocles has an eccentric theory about biological evolution, which shows that Pythagoras tends to think in terms of units, even though units do not necessarily have numerical significance. From the beginning, empedocles imagined that all parts of animals and people, such as eyes, legs, arms and heads, wandered independently. These units happened to be combined, partly because of the attraction of love, which gave birth to modern creatures and various monsters. Some have many legs, some are cows, but these are barren, and only those with the necessary survival attributes are left behind:

"Many species of creatures must not continue to reproduce in the past: because any species that exists now has protected and preserved itself through strategy or courage or speed at birth."

Those atomists took the unit's view of nature one step further, expanding from the biological world to the physical world. The early atomists were leucippus of Miletus (about 440 BC) and Democritus of Abdila (about 420 BC), and their contributions were inseparable. They think that everything in the universe is made up of atoms, and atoms are inseparable substances. There are countless atoms in the universe, and they are always moving in the infinite void. They have existed since ancient times, because they can neither be created nor destroyed. Atoms vary in size, shape and possible weight. Atoms rely on their motion in the void (mostly vortex motion) to drive larger atoms to the center of the vortex, where the earth was formed. This large soil atom is interconnected, so its function is limited; They can only jump or vibrate. Fine atoms of water, gas and fire are driven into space, resulting in a swirling motion around the earth. Large atoms outside the earth gather together to form a wet mass, which dries and burns when passing through the vortex. These are celestial bodies. Because the number of atoms is infinite, and the space in which they run is infinite, there are many worlds, some of which are produced and some of which are extinct. Some worlds have no sun and moon, and some worlds have several, but they all have a beginning and an end. Like most Ionian philosophers, democritus thought the earth was a cylinder, not a sphere as Pythagoras thought.

Atomists believe that life developed from primitive clay, so did plants, animals and people. Man is the epitome of the universe because he contains all kinds of atoms. Life and soul are like fire, because they are all made up of small spherical atoms. This kind of atom is often expelled from the human body and absorbed from the air, so when breathing stops, life is over. The atomist's view of the world is completely mechanical; Everything is predetermined-"Everything in the past, present and future must be predetermined". They do not use metaphors such as human purpose, love and struggle or the principle of revenge to explain the activities of the world. In this regard, it is worth mentioning that Prota protagoras, a contemporary of democritus, once put forward the view that criminals should be punished, not for revenge, but to prevent further crimes.

There are three main trends in early Greek medicine. The first, perhaps the earliest, was a temple medicine dedicated to the medical god Schula Bis. The second is the philosophy and medicine of Pythagoras school in southern Italy. The third is the more practical Ionian school of Hippocrates. The works of Hippocrates are the earliest medical documents in Greece, which can be traced back to the fourth century BC. These medical works are not so much written by individuals as collective works of a school, and Hippocrates of Coase (about 460-377 BC) is just an outstanding figure of this school. This school regards medicine as an art or technology, rather than a theoretical science like Pythagoras, although they have also developed their own theories. They founded a theory that the human body has four kinds of body fluids, namely black bile, blood, yellow bile and mucus. When four kinds of body fluids are mixed together, people will be healthy, and when any one comes out, people will get sick. This theory seems to be based on the observation of four substances in blood: one is black blood clot, which represents black bile; A red liquid, equivalent to blood; A yellow flesh, namely yellow bile; A fibrin is related to mucus.