Pre-Socratic Philosophers Essay

â€Å"Pre-Socratic† is the expression commonly used to describe those Greek thinkers who lived and wrote between 600 and 400 B.C. It was the Pre-Socratics who attempted to find universal principles which would explain the natural world from its origins to man’s place in it. Although Socrates died in 399 B.C., the term â€Å"Pre-Socratic† indicates not so much a chronological limit, but rather an outlook or range of interests, an outlook attacked by both Protagoras (a Sophist) and Socrates, because natural philosophy was worthless when compared with the search for the â€Å"good life.†To give the Pre-Socratic thinkers their full due would require an article of encyclopedic scope. Given that, I have decided to list a number of sites on individual Pre-Socratic thinkers.Anaximander1. Life and SourcesThe history of written Greek philosophy starts with Anaximander of Miletus in Asia Minor, a fellow-citizen of Thales. He was the first who dared to write a treatise in prose, which has been called traditionally On Nature. This book has been lost, although it probably was available in the library of the Lyceum at the times of Aristotle and his successor Theophrastus. It is said that Apollodorus, in the second century BCE, stumbled upon a copy of it, perhaps in the famous library of Alexandria. Recently, evidence has appeared that it was part of the collection of the library of Taormina in Sicily, where a fragment of a catalogue has been found, on which Anaximander’s name can be read. Only one fragment of the book has come down to us, quoted by Simplicius (after Theophrastus), in the sixth century AD. It is perhaps the most famous and most discussed phrase in the history of philosophy.We also know very little of Anaximander’s life. He is said to have led a mission that founded a colony called Apollonia on the coast of the Black Sea. He also probably introduced the gnomon (a perpendicular sun-dial) into Greece and erected one in Sparta. So he seems to have been a much-traveled man, which is not astonishing, as the Milesians were known to be audacious sailors. It is also reported that he displayed solemn manners and wore pompous garments. Most of the information on Anaximander comes from Aristotle and his pupil Theophrastus, whose book on the history of philosophy was used, excerpted, and quoted by many other authors, the so-called doxographers, before it was lost. Sometimes, in these texts words or expressions appear that can with some certainty be ascribed  to Anaximander himself. Relatively many testimonies, approximately one third of them, have to do with astronomical and cosmological questions. Hermann Diels and Walter Kranz have edited the doxography (A) and the existing texts (B) of the Presocratic philosophers in Die Fragmente der Vorsokratiker, Berlin 1951-19526. (A quotation like â€Å"DK 12A17†³ means: â€Å"Diels/Kranz, Anaximander, doxographical report no.17†³).| 2. The â€Å"Boundless† as Principle According to Aristotle and Theophrastus, the first Greek philosophers were looking for the â€Å"origin† or â€Å"principle† (the Greek word â€Å"archà ªÃ¢â‚¬  has both meanings) of all things. Anaximander is said to have identified it with â€Å"the Boundless† or â€Å"the Unlimited† (Greek: â€Å"apeiron,† that is, â€Å"that which has no boundaries†). Already in ancient times, it is complained that Anaximander did not explain what he meant by â€Å"the Boundless.† More recently, authors have disputed whether the Boundless should be interpreted as spatially or temporarily without limits, or perhaps as that which has no qualifications, or as that which is inexhaustible. Some scholars have even defended the meaning â€Å"that which is not experienced,† by relating the Greek word â€Å"apeiron† not to â€Å"peras† (â€Å"boundary,† â€Å"limit†), but to â€Å"perao† (â€Å"to experience,â⠂¬  â€Å"to apperceive†). The suggestion, however, is almost irresistible that Greek philosophy, by making the Boundless into the principle of all things, has started on a high level of abstraction. On the other hand, some have pointed out that this use of â€Å"apeiron† is atypical for Greek thought, which was occupied with limit, symmetry and harmony. The Pythagoreans placed the boundless (the â€Å"apeiron†) on the list of negative things, and for Aristotle, too, perfection became aligned with limit (Greek: â€Å"peras†), and thus â€Å"apeiron† with imperfection. Therefore, some authors suspect eastern (Iranian) influence on Anaximander’s ideas. Anaximenes (d. 528 BCE) According to the surviving sources on his life, Anaximenes flourished in the mid 6th century BCE and died around 528. He is the third philosopher of the Milesian School of philosophy, so named because like Thales and Anaximander, Anaximenes was an inhabitant of Miletus, in Ionia (ancient Greece). Theophrastus notes that Anaximenes was an associate, and possibly a student, of Anaximander’s. Anaximenes is best known for his doctrine that air is the source of all things. In this way, he differed with his predecessors like Thales, who held that water is the source of all things, and Anaximander, who thought that all things came from an unspecified boundless stuff. 2. Doctrine of Change Given his doctrine that all things are composed of air, Anaximenes suggested an interesting qualitative account of natural change: [Air] differs in essence in accordance with its rarity or density. When it is thinned it becomes fire, while when it is condensed it becomes wind, then cloud, when still more condensed it becomes water, then earth, then stones. Everything else comes from these. (DK13A5) Influence on later Philosophy Anaximenes’ theory of successive change of matter by rarefaction and condensation was influential in later theories. It is developed by Heraclitus (DK22B31), and criticized by Parmenides (DK28B8.23-24, 47-48). Anaximenes’ general theory of how the materials of the world arise is adopted by Anaxagoras(DK59B16), even though the latter has a very different theory of matter. Both Melissus (DK30B8.3) and Plato (Timaeus 49b-c) see Anaximenes’ theory as providing a common-sense explanation of change. Diogenes of Apollonia makes air the basis of his explicitly monistic theory. The Hippocratic treatise On Breaths uses air as the central concept in a theory of diseases. By providing cosmological accounts with a theory of change, Anaximenes separated them from the realm of mere speculation and made them, at least in conception, scientific theories capable of testing. Thales of Miletus (c. 620 BCE – c. 546 BCE) The ancient Greek philosopher Thales was born in Miletus in Greek Ionia. Aristotle, the major source for Thales’s philosophy and science, identified Thales as the first person to investigate the basic principles, the question of the originating substances of matter and, therefore, as the founder of the school of natural philosophy. Thales was interested in almost everything, investigating almost all areas of knowledge, philosophy, history, science, mathematics, engineering, geography, and politics. He  proposed theories to explain many of the events of nature, the primary substance, the support of the earth, and the cause of change. Thales was much involved in the problems of astronomy and provided a number of explanations of cosmological events which traditionally involved supernatural entities. His questioning approach to the understanding of heavenly phenomena was the beginning of Greek astronomy. Thales’ hypotheses were new and bold, and in freeing phenomena from godly intervention, he paved the way towards scientific endeavor. He founded the Milesian school of natural philosophy, developed the scientific method, and initiated the first western enlightenment. A number of anecdotes is closely connected to Thales’ investigations of the cosmos. When considered in association with his hypotheses they take on added meaning and are most enlightening. Thales was highly esteemed in ancient times, and a letter cited by Diogenes Laertius, and purporting to be from Anaximenes to Pythagoras, advised that all our discourse should begin with a reference to Thales (D.L. II.4). 1. The Writings of Thales Doubts have always existed about whether Thales wrote anything, but a number of ancient reports credit him with writings. Simplicius (Diels, Dox. p. 475) specifically attributed to Thales authorship of the so-called Nautical Star-guide. Diogenes Laertius raised doubts about authenticity, but wrote that ‘according to others [Thales] wrote nothing but two treatises, one On the Solstice and one On the Equinox‘ (D.L. I.23). Lobon of Argus asserted that the writings of Thales amounted to two hundred lines (D.L. I.34), and Plutarch associated Thales with opinions and accounts expressed in verse (Plutarch, De Pyth. or. 18. 402 E). Hesychius, recorded that ‘[Thales] wrote on celestial matters in epic verse, on the equinox, and much else’ (DK, 11A2). Callimachus credited Thales with the sage advice that navigators should navigate by Ursa Minor (D.L. I.23), advice which may have been in writing. Diogenes mentions a poet, Choerilus, who declared that ‘[Thales] was the first to maintain the immortality of the soul’ (D.L. I.24), and in De Anima, Aristotle’s words ‘from what is recorded about [Thales]‘, indicate that Aristotle was working from a written source. Diogenes recorded that  Ã¢â‚¬Ëœ[Thales] seems by some accounts to have been the first to study astronomy, the first to predict eclipses of the sun and to fix the solstices; so Eudemus in his History of Astronomy. It was this which gained for him the admiration of Xenophanes and Herodotus and the notice of Heraclitus and Democritus’ (D.L. I.23). Eudemus who wrote a History of Astronomy, and also on geometry and theology, must be considered as a possible source for the hypotheses of Thales. The information provided by Diogenes is the sort of material which he would have included in his History of Astronomy, and it is possible that the titles On the Solstice, and On the Equinox were a vailable to Eudemus. Xenophanes, Herodotus, Heraclitus and Democritus were familiar with the work of Thales, and may have had a work by Thales available to them. A solstice is an astronomical event that happens twice each year when the Sun reaches its highest position in the sky as seen from the North or South Pole. The word solstice is derived from the Latin sol (sun) and sistere (to stand still), because at the solstices, the Sun stands still in declination; that is, the seasonal movement of the Sun’s path (as seen from Earth) comes to a stop before reversing direction. The solstices, together with the equinoxes, are connected with the seasons. In many cultures the solstices mark either the beginning or the midpoint of winter and summer. The term solstice can also be used in a broader sense, as the date (day) when this occurs. The day of the solstice is either the â€Å"longest day of the year† (in summer) or the â€Å"shortest day of the year† (in winter) for any place on Earth, because the length of time between sunrise and sunset on that day is the yearly maximum or minimum for that place. Proclus recorded that Thales was followed by a great wealth of geometers, most of whom remain as honoured names. They commence with Mamercus, who was a pupil of Thales, and include Hippias of Elis, Pythagoras, Anaxagoras, Eudoxus of Cnidus, Philippus of Mende, Euclid, and Eudemus, a friend of Aristotle, who wrote histories of arithmetic, of astronomy, and of geometry, and many lesser known names. It is possible that writings of Thales were available to some of these men. Any records which Thales may have kept would have been an advantage in his own work. This is especially true of mathematics, of the dates and times determined when fixing the solstices, the positions of stars, and in  financial transactions. It is difficult to believe that Thales would not have written down the information he had gathered in his travels, particularly the geometry he investigated in Egypt and his measuring of the height of the pyramid, his hypotheses about nature, and the cause of change. Proclus acknowledged Thales as the discoverer of a number of specific theorems (A Commentary on the First Book of Euclid’s Elements 65. 8-9; 250. 16-17). This suggests that Eudemus, Proclus’s source had before him the written records of Thales’s discoveries. How did Thales ‘prove’ his theorems if not in written words and sketches? The works On the Solstice, On the Equinox, which were attributed to Thales (D.L. I.23), and the ‘Nautical Star guide, to which Simplicius referred, may have been sources for the History of Astronomy of Eudemus (D.L. I.23). Pythagoras (c.570—c.495 BCE) The pre-Socratic Greek philosopher Pythagoras must have been one of the world’s greatest persons, but he wrote nothing, and it is hard to say how much of the doctrine we know as Pythagorean is due to the founder of the society and how much is later development. It is also hard to say how much of what we are told about the life of Pythagoras is trustworthy; for a mass of legend gathered around his name at an early date. Sometimes he is represented as a man of science, and sometimes as a preacher of mystic doctrines, and we might be tempted to regard one or other of those characters as alone historical. The truth is that there is no need to reject either of the traditional views. The union of mathematical genius and mysticism is common enough. Originally from Samos, Pythagoras founded at Kroton (in southern Italy) a society which was at once a religious community and a scientific school. Such a body was bound to excite jealousy and mistrust, and we hear of many struggles. Pythagoras himself had to flee from Kroton to Metapontion, where he died. It is stated that he was a disciple of Anaximander, his astronomy was the natural development of Anaximander’s. Also, the way in which the Pythagorean geometry developed also bears witness to its descent from that of Miletos. The great problem at this date was the duplication of the square, a problem which gave rise to the theorem of the square on the hypotenuse, commonly  known still as the Pythagorean proposition (Euclid, I. 47). If we were right in assuming that Thales worked with the old 3:4:5 triangle, the connection is obvious. Pythagoras argued that there are three kinds of men, just as there are three classes of strangers who come to the Olympic Games. The lowest consists of those who come to buy and sell, and next above them are those who come to compete. Best of all are those who simply come to look on. Men may be classified accordingly as lovers of wisdom, lovers of honor, and lovers of gain. That seems to imply the doctrine of the tripartite soul, which is also attributed to the early Pythagoreans on good authority, though it is common now to ascribe it to Plato. There are, however, clear references to it before his time, and it agrees much better with the general outlook of the Pythagoreans. The comparison of human life to a gathering like the Games was often repeated in later days. Pythagoras also taught the doctrine of Rebirth or transmigration, which we may have learned from the contemporary Orphics. Xenophanes made fun of him for pretending to recognize the voice of a departed friend in the howls of a beaten dog. Empedocles seems to be referring to him when he speaks of a man who could remember what happened ten or twenty generations before. It was on this that the doctrine of Recollection, which plays so great a part in Plato, was based. The things we perceive with the senses, Plato argues, remind us of things we knew when the soul was out of the body and could perceive reality directly. There is more difficulty about the cosmology of Pythagoras. Hardly any school ever professed such reverence for its founder’s authority as the Pythagoreans. ‘The Master said so’ was their watchword. On the other hand, few schools have shown so much capacity for progress and for adapting themselves to new conditions. Pythagoras started from the cosmical system of Anaximenes. Aristotle tells us that the Pythagoreans represented the world as inhaling ‘air’ form the boundless mass outside it, and this ‘air’ is identified with ‘the unlimited’. When, however, we come to the process by which things are developed out of the ‘unlimited’, we observe a great change. We hear nothing more of ‘separating out’ or even of rarefaction and condensation. Instead of that we have the theory that what gives form to the  Unlimited is the Limit. That is the great contribution of Pythagoras to philosophy, and we must try to understand it. Now the function of the Limit is usually illustrated from the arts of music and medicine, and we have seen how important these two arts were for Pythagoreans, so it is natural to infer that the key to its meaning is to be found in them. It may be taken as certain that Pythagoras himself discovered the numerical ratios which determine the concordant intervals of the musical scale. Similar to musical intervals, in medicine there are opposites, such as the hot and the cold, the wet and the dry, and it is the business of the physician to produce a proper ‘blend’ of these in the human body. In a well-known passage of Plato’s Phaedo (86 b) we are told by Simmias that the Pythagoreans held the body to be strung like an instrument to a certain pitch, hot and cold, wet and dry taking the place of high and low in music. Musical tuning and health are alike means arising from the application of Limit to the Unlimited. It was natural for Pythagoras to look for something of the same kind in the world at large. Briefly stated, the doctrine of Pythagoras was that all things are numbers. In certain fundamental cases, the early Pythagoreans represented numbers and explained their properties by means of dots arrang ed in certain ‘figures’ or patterns. Zeno’s Paradoxes In the fifth century B.C.E., Zeno of Elea offered arguments that led to conclusions contradicting what we all know from our physical experience–that runners run, that arrows fly, and that there are many different things in the world. The arguments were paradoxes for the ancient Greek philosophers. Because most of the arguments turn crucially on the notion that space and time are infinitely divisible—for example, that for any distance there is such a thing as half that distance, and so on—Zeno was the first person in history to show that the concept of infinity is problematical. In his Achilles Paradox, Achilles races to catch a slower runner–for example, a tortoise that is crawling away from him. The tortoise has a head start, so if Achilles hopes to overtake it, he must run at least to the place where the tortoise presently is, but by the time he arrives there, it will have crawled to a new place, so then Achilles must run to this new place, but the  tortoise meanwhile will have crawled on, and so forth. Achilles will never catch the tortoise, says Zeno. Therefore, good reasoning shows that fast runners never can catch slow ones. So much the worse for the claim that motion really occurs, Zeno says in defense of his mentor Parmenides who had argued that motion is an illusion. Although practically no scholars today would agree with Zeno’s conclusion, we can not escape the paradox by jumping up from our seat and chasing down a tortoise, nor by saying Achilles should run to some other target place ahead of where the tortoise is at the moment. What is required is an analysis of Zeno’s own argument that does not get us embroiled in new paradoxes nor impoverish our mathematics and science. This article explains his ten known paradoxes and considers the treatments that have been offered. Zeno assumed distances and durations can be divided into an actual infinity (what we now call a transfinite infinity) of indivisible parts, and he assumed these are too many for the runner to complete. Aristotle‘s treatment said Zeno should have assumed there are only potential infinities, and that neither places nor times divide into indivisible parts. His treatment became the generally accepted solution until the late 19th century. The current standard treatment says Zeno was right to conclude that a runner’s path contains an actual infinity of parts, but he was mistaken to assume this is too many. This treatment employs the apparatus of calculus which has proved its indispensability for the development of modern science. In the twentieth century it finally became clear that disallowing actual infinities, as Aristotle wanted, hampers the growth of set theory and ultimately of mathematics and physics. This standard treatment took hundreds of years to perfect and was due to the flexibility of intellectuals who were willing to replace old theories and their concepts with more fruitful ones, despite the damage done to common sense and our naive intuitions. The article ends by exploring newer treatments of the paradoxes—and related paradoxes such as Thomson’s Lamp Paradox—that were developed since the 1950s. Parmenides (b. 510 BCE) Parmenides was a Greek philosopher and poet, born of an illustrious family about BCE. 510, at Elea in Lower Italy, and is is the chief representative of the Eleatic philosophy. He was held in high esteem by his fellow-citizens for his excellent legislation, to which they ascribed the prosperity and wealth of the town. He was also admired for his exemplary life. A â€Å"Parmenidean life† was proverbial among the Greeks. He is commonly represented as a disciple of Xenophanes. Parmenides wrote after Heraclitus, and in conscious opposition to him, given the evident allusion to Hericlitus: â€Å"for whom it is and is not, the same and not the same, and all things travel in opposite directions† (fr. 6, 8). Little more is known of his biography than that he stopped at Athens on a journey in his sixty-fifth year, and there became acquainted with the youthful Socrates. That must have been in the middle of the fifth century BCE., or shortly after it. Parmenides broke with the older Ionic prose tradition by writing in hexameter verse. His didactic poem, called On Nature, survives in fragments, although the Proem (or introductory discourse) of the work has been preserved. Parmenides was a young man when he wrote it, for the goddess who reveals the truth to him addresses him as â€Å"youth.† The work is considered inartistic. Its Hesiodic style was appropriate for the cosmogony he describes in the second part, but is unsuited to the arid dialectic of the first. Parmenides was no born poet, and we must ask what led him to take this new departure. The example of Xenophanes’ poetic writings is not a complete explanation; for the poetry of Parmenides is as unlike that of Xenophanes as it well can be, and his style is more like Hesiod and the Orphics. In the Proem Parmenides describes his ascent to the home of the goddess who is supposed to speak the remainder of the verses; this is a reflexion of the conventional ascents i nto heaven which were almost as common as descents into hell in the apocalyptic literature of those days. The Proem opens with Parmenides representing himself as borne on a chariot and attended by the Sunmaidens who have quitted the Halls of Night to guide him on his journey. They pass along the highway till they come to the Gate of Night and Day, which is locked and barred. The key is in the keeping of Dike (Right), the Avenger, who is persuaded to unlock it by the Sunmaidens.  They pass in through the gate and are now, of course, in the realms of Day. The goal of the journey is the palace of a goddess who welcomes Parmenides and instructs him in the two ways, that of Truth and the deceptive way of Belief, in which is no truth at all. All this is described without inspiration and in a purely conventional manner, so it must be interpreted by the canons of the apocalyptic style. It is clearly meant to indicate that Parmenides had been converted, that he had passed from error (night) to truth (day), and the Two Ways must represent his former error and the truth which is now revealed to h im. There is reason to believe that the Way of Belief is an account of Pythagorean cosmology. In any case, it is surely impossible to regard it as anything else than a description of some error. The goddess says so in words that cannot be explained away. Further, this erroneous belief is not the ordinary man’s view of the world, but an elaborate system, which seems to be a natural development the Ionian cosmology on certain lines, and there is no other system but the Pythagorean that fulfils this requirement. To this it has been objected that Parmenides would not have taken the trouble to expound in detail a system he had altogether rejected, but that is to mistake the character of the apocalyptic convention. It is not Parmenides, but the goddess, that expounds the system, and it is for this reason that the beliefs described are said to be those of ‘mortals’. Now a description of the ascent of the soul would be quite incomplete without a picture of the region from which it had escaped. The goddess must reveal the two ways at the parting of which Parmenides stands, and bid him choose the better. The rise of mathematics in the Pythagorean school had revealed for the first time the power of thought. To the mathematician of all men it is the same thing that can be thought and that can be, and this is the principle from which Parmenides starts. It is impossible to think what is not, and it is impossible for what cannot be thought to be. The great question, Is it or is it not? is therefore equivalent to the question, Can it be thought or not? In any case, the work thus has two divisions. The first discusses the truth, and the second the world of illusion — that is, the world of the senses and the erroneous opinions of mankind founded upon them. In his opinion truth  lies in the perception that existence is, and error in the idea that non-existence also can be. Nothing can have real existence but what is conceivable; therefore to be imagined and to be able to exist are the same thing, and there is no development. The essence of what is conceivable is incapable of development, imperishable, immutable, unbounded, and indivisible. What is various and mutable, all development, is a delusive phantom. Perception is thought directed to the pure essence of being; the phenomenal world is a delusion, and the opinions formed concerning it can only be improbable. Parmenides goes on to consider in the light of this principle the consequences of saying that anything is. In the first place, it cannot have come into being. If it had, it must have arisen from nothing or from something. It cannot have arisen from nothing; for there is no nothing. It cannot have arisen from something; for here is nothing else than what is. Nor can anything else besides itself come into being; for there can be no empty space in which it could do so. Is it or is it not? If it is, then it is now, all at once. In this way Parmenides refutes all accounts of the origin of the world. Ex nihilo nihil fit. Further, if it is, it simply is, and it cannot be more or less. There is, therefore, as much of it in one place as in another. (That makes rarefaction and condensation impossible.) it is continuous and indivisible; for there is nothing but itself which could prevent its parts being in contact with one another. It is therefore full, a continuous indivisible plenum. (That is directed against the Pythagorean theory of a discontinuous reality.) Further, it is immovable. If it moved, it must move into empty space, and empty space is nothing, and there is no nothing. Also it is finite and spherical; for it cannot be in one direction any more than in another, and the sphere is the only figure of which this can be said. What is, therefore a finite, spherical, motionless, continuous plenum, and there is nothing beyond it. Coming into being and ceasing to be are mere ‘names’, and so is motion, and still more color and the like. They are not even thoughts; for a thought must be a thought of something that is, and none of these can be. Such is the conclusion to which the view of the real as a single body inevitably leads, and there is no escape from it. The ‘matter’ of our physical text-books is just the real of Parmenides; and, unless we can find room for something else than matter, we are shut up into his account of reality. No subsequent system could afford to ignore this, but of course it was impossible to acquiesce permanently in a doctrine like that of Parmenides. It deprives the world we know of all claim to existence, and reduces it to something which is hardly even an illusion. If we are to give an intelligible account of the world, we must certainly introduce motion again somehow. That can never be taken for granted any more, as it was by the early cosmologists; we must attempt to explain it if we are to escape from the conclusions of Parmenides. Heraclitus (fl. c.500 BCE) A Greek philosopher of the late 6th century BCE, Heraclitus criticizes his predecessors and contemporaries for their failure to see the unity in experience. He claims to announce an everlasting Word (Logos) according to which all things are one, in some sense. Opposites are necessary for life, but they are unified in a system of balanced exchanges. The world itself consists of a law-like interchange of elements, symbolized by fire. Thus the world is not to be identified with any particular substance, but rather with an ongoing process governed by a law of change. The underlying law of nature also manifests itself as a moral law for human beings. Heraclitus is the first Western philosopher to go beyond physical theory in search of metaphysical foundations and moral applications. Anaxagoras (c.500—428 BCE) Anaxagoras of Clazomenae was an important Presocratic natural philosopher and scientist who lived and taught in Athens for approximately thirty years. He gained notoriety for his materialistic views, particularly his contention that the sun was a fiery rock. This led to charges of impiety, and he was sentenced to death by the Athenian court. He avoided this penalty by leaving Athens, and he spent his remaining years in exile. While Anaxagoras proposed theories on a variety of subjects, he is most noted for two theories. First, he speculated that in the physical world everything contains a portion of everything else. His observation of how nutrition works in animals led him to conclude that in order for the food an animal eats to turn into bone,  hair, flesh, and so forth, it must already contain all of those constituents within it. The second theory of significance is Anaxagoras’ postulation of Mind (Nous) as the initiating and governing principle of the cosmos. Democritus ( 460—370 BCE) Democritus was born at Abdera, about 460 BCE, although according to some 490. His father was from a noble family and of great wealth, and contributed largely towards the entertainment of the army of Xerxes on his return to Asia. As a reward for this service the Persian monarch gave and other Abderites presents and left among them several Magi. Democritus, according to Diogenes Laertius, was instructed by these Magi in astronomy and theology. After the death of his father he traveled in search of wisdom, and devoted his inheritance to this purpose, amounting to one hundred talents. He is said to have visited Egypt, Ethiopia, Persia, and India. Whether, in the course of his travels, he visited Athens or studied under Anaxagoras is uncertain. During some part of his life he was instructed in Pythagoreanism, and was a disciple of Leucippus. After several years of traveling, Democritus returned to Abdera, with no means of subsistence. His brother Damosis, however, took him in. According to the law of Abdera, whoever wasted his patrimony would be deprived of the rites of burial. Democritus, hoping to avoid this disgrace, gave public lectures. Petronius relates that he was acquainted with the virtues of herbs, plants, and stones, and that he spent his life in making experiments upon natural bodies. He acquired fame with his knowledge of natural phenomena, and predicted changes in the weather. He used this ability to make people believe that he could predict future events. They not only viewed him as something more than mortal, but even proposed to put him in control of their public affairs. He preferred a contemplative to an active life, and therefore declined these public honors and passed the remainder of his days in solitude. Credit cannot be given to the tale that Democritus spent his leisure hours in chemical researches after the philosopher’s stone — the dream of a later age; or to the story of his conversation with Hippocrates concerning Democritus’s supposed madness, as based on spurious letters. Democritus has been commonly known as â€Å"The Laughing Philosopher,† and it is gravely related  by Seneca that he never appeared in public with out expressing his contempt of human follies while laughing. Accordingly, we find that among his fellow-citizens he had the name of â€Å"the mocker†. He died at more than a hundred years of age. It is said that from then on he spent his days and nights in caverns and sepulchers, and that, in order to master his intellectual faculties, he blinded himself with burning glass. This story, however, is discredited by the writers who mention it insofar as they say he wrote books and dissected animals, neither of which could be done we ll without eyes. Democritus expanded the atomic theory of Leucippus. He maintained the impossibility of dividing things ad infinitum. From the difficulty of assigning a beginning of time, he argued the eternity of existing nature, of void space, and of motion. He supposed the atoms, which are originally similar, to be impenetrable and have a density proportionate to their volume. All motions are the result of active and passive affection. He drew a distinction between primary motion and its secondary effects, that is, impulse and reaction. This is the basis of the law of necessity, by which all things in nature are ruled. The worlds which we see — with all their properties of immensity, resemblance, and dissimilitude — result from the endless multiplicity of falling atoms. The human soul consists of globular atoms of fire, which impart movement to the body. Maintaining his atomic theory throughout, Democritus introduced the hypothesis of images or idols (eidola), a kind of emanation from external objects, which make an impression on our senses, and from the influence of which he deduced sensation (aesthesis) and thought (noesis). He distinguished between a rude, imperfect, and therefore false perception and a true one. In the same manner, consistent with this theory, he accounted for the popular notions of Deity; partly through our incapacity to understand fully the phenomena of which we are witnesses, and partly from the impressions communicated by certain beings (eidola) of enormous stature and resembling the human figure which inhabit the air. We know these from dreams and the causes of divination. He carried his theory into practical philosophy also, laying down that happiness consisted in an even temperament. From this he deduced his moral principles and prudential maxims. It was from Democritus that  Epicurus borrowed the princi pal features of his philosophy. Empedocles (c.492—432 BCE) Empedocles (of Acagras in Sicily) was a philosopher and poet: one of the most important of the philosophers working before Socrates (the Presocratics), and a poet of outstanding ability and of great influence upon later poets such as Lucretius. His works On Nature and Purifications (whether they are two poems or only one – see below) exist in more than 150 fragments. He has been regarded variously as a materialist physicist, a shamanic magician, a mystical theologian, a healer, a democratic politician, a living god, and a fraud. To him is attributed the invention of the four-element theory of matter (earth, air, fire, and water), one of the earliest theories of particle physics, put forward seemingly to rescue the phenomenal world from the static monism of Parmenides. Empedocles’ world-view is of a cosmic cycle of eternal change, growth and decay, in which two personified cosmic forces, Love and Strife, engage in an eternal battle for supremacy. In psychology and ethics Empedocles was a follower of Pythagoras, hence a believer in the transmigration of souls, and hence also a vegetarian. He claims to be a daimà ´n, a divine or potentially divine being, who, having been banished from the immortals gods for ‘three times countless years’ for committing the sin of meat-eating and forced to suffer successive reincarnations in an purificatory journey through the different orders of nature and elements of the cosmos, has now achieved the most perfect of human states and will be reborn as an immortal. He also claims seemingly magical powers including the ability to revive the dead and to control the winds and rains.