Even if the eclipse of had been visible to the Near-Eastern astronomers, it is not possible to recognize a pattern from witnessing one event, or indeed, from witnessing two events. One may suggest a pattern after witnessing three events that are separated by equal periods of time, but the eclipse which preceded that of , and which occurred on 6th May , was not visible in Near-Eastern regions. It is quite wrong to say that eclipses repeat themselves with very little change, because each solar eclipse in a particular Saros occurs about 7.
Adding to the difficulty of recognizing a particular cycle is the fact that about forty-two periodic cycles are in progress continuously, and overlapping at any time.
Every series in a periodic cycle lasts about 1, years and comprises 73 eclipses. Eclipses which occur in one periodic cycle are unrelated to eclipses in other periodic cycles. The ancient letters prove that the Babylonians and Assyrians knew that lunar eclipses can occur only at full moon, and solar eclipses only at new moon, and also that eclipses occur at intervals of five or six months.
Recent opinion is that, as early as B. In other recent research Britton has analysed a text known as Text S, which provides considerable detail and fine analysis of lunar phenomena dating from Nabonassar in B. The text points to knowledge of the six-month five month periods.
Britton believes that the Saros cycle was known before B. There is no evidence that the Saros could have been used for the prediction of solar eclipses in the sixth century B. The Babylonian and Assyrian astronomers knew of the Saros period in relation to lunar eclipses, and had some success in predicting lunar eclipses but, in the sixth century B. It is testified that Thales knew that the sun is eclipsed when the moon passes in front of it, the day of eclipse — called the thirtieth by some, new moon by others The Oxyrhynchus Papyri, However, lunar eclipses are not always followed by solar eclipses.
A report from Theon of Smyrna ap. Diogenes Laertius I. Solstices are natural phenomena which occur on June 21 or 22, and December 21 or 22, but the determination of the precise date on which they occur is difficult. It is the reason why the precise determination of the solstices was so difficult. It was a problem which engaged the early astronomers, and more than seven centuries later, Ptolemy acknowledged the difficulty Alm. This suggests that Thales observed the rising and setting of the sun for many days at mid-summer and mid-winter and, necessarily, over many years.
Mount Mycale, being the highest point in the locality of Miletus, would provide the perfect vantage point from which to make observations. Another method which Thales could have employed was to measure the length of the noon-day sun around mid-summer and mid-winter. Again this would require observations to be made, and records kept over many days near the solstice period, and over many years.
Because Thales had determined the solstices, he would have known of the number of days between say, summer solstices, and therefore have known the length of a solar year.
It is consistent with his determination of the solstices that he should be credited with discovering that days comprise a year. It is also a fact that had long been known to the Egyptians who set their year by the more reliable indicator of the annual rising of the star Sirius in July.
Thales may have first gained the knowledge of the length of the year from the Egyptians, and perhaps have attempted to clarify the matter by using a different procedure.
Florida, Following soon after Apuleius, Cleomedes explained that the calculation could be made by running a water-clock, from which the result was obtained: the diameter of the sun is found to be one seven-hundred-and-fiftieth of its own orbit Cleomedes, De Motu circulari corporum caelestium, II. Little credence can be given to the water-clock method for reaching this determination, because there is an inbuilt likelihood of repeated errors over the 24 hour period.
Even Ptolemy, who flourished in the second century A. In his work in geometry, Thales was engaged in circles and angles, and their characteristics, and he could have arrived at his solution to the problem by applying the geometrical knowledge he had acquired.
There is no evidence to support a suggestion that Thales was familiar with measurements by degrees but he could have learnt, from the Babylonians, that a circle is divided into The figure of , which was given by Diogenes for Thales, is double , and this is related to the Babylonian sexagesimal system. To establish the dates of the solstices, Thales probably made repeated observations of the risings and settings of the sun. Of the report from Diogenes Laertius D. Callimachus D. This means only that he recognized the advantages of navigating by Ursa Minor, rather than by Ursa Major, as was the preferred method of the Greeks.
Ursa Minor, a constellation of six stars, has a smaller orbit than does the Great Bear, which means that, as it circles the North Pole, Ursa Minor changes its position in the sky to a lesser degree than does the Great Bear.
Thales offered this sage advice to the mariners of Miletus, to whom it should have been of special value because Miletus had developed a maritime trade of economic importance. In Theaetetus A Plato had Socrates relate a story that Thales was so intent upon watching the stars that he failed to watch where he was walking, and fell into a well. The story is also related by Hippolytus Diels, Dox. If Thales had heard that stars could be viewed to greater advantage from wells, either during day or night, he would surely have made an opportunity to test the theory, and to take advantage of a method that could assist him in his observations.
The possibility that the story was based on fact should not be overlooked. Plato had information which associated Thales with stars, a well, and an accident. Whether Thales fell into a well, or tripped when he was getting in or out of a well, the story grew up around a mishap. The practical skill of land measurement was invented in Egypt because of the necessity frequently to remeasure plots of land after destructive inundations. The phenomena is well described by Herodotus II. Egypt was believed to be the source of much wisdom and reports tell us that many Greeks, including Thales, Pythagoras, Solon, Herodotus, Plato, Democritus, and Euclid, visited that ancient land to see the wonders for themselves.
The Egyptians had little to offer in the way of abstract thought. The surveyors were able to measure and to calculate and they had outstanding practical skills.
In Egypt Thales would have observed the land surveyors, those who used a knotted cord to make their measurements, and were known as rope-stretchers. Egyptian mathematics had already reached its heights when The Rhind Mathematical Papyrus was written in about B. More than a thousand years later, Thales would have watched the surveyors as they went about their work in the same manner, measuring the land with the aid of a knotted rope which they stretched to measure lengths and to form angles.
Proclus provided a remarkable amount of intriguing information, the vital points of which are the following: Geometry originated in Egypt where it developed out of necessity; it was adopted by Thales who had visited Egypt, and was introduced into Greece by him. The Commentary of Proclus indicates that he had access to the work of Euclid and also to The History of Geometry which was written by Eudemus of Rhodes, a pupil of Aristotle, but which is no longer extant.
His wording makes it clear that he was familiar with the views of those writers who had earlier written about the origin of geometry. He affirmed the earlier views that the rudiments of geometry developed in Egypt because of the need to re-define the boundaries, just as Herodotus stated. Five Euclidean theorems have been explicitly attributed to Thales, and the testimony is that Thales successfully applied two theorems to the solution of practical problems.
Thales did not formulate proofs in the formal sense. The process Thales used was the method of exhaustion. It seems that Thales discovered only the first part of this theorem for Proclus reported: We are indebted to old Thales for the discovery of this and many other theorems.
For he, it is said, was the first to notice and assert that in every isosceles the angles at the base are equal, though in somewhat archaic fashion he called the equal angles similar Proclus, This theorem is positively attributed to Thales.
Proof of the theorem dates from the Elements of Euclid Proclus, Thales applied this theorem to determine the height of a pyramid. The great pyramid was already over two thousand years old when Thales visited Gizeh, but its height was not known.
He introduced the concept of ratio, and recognized its application as a general principle. It is considered that the general principle in Euclid I. Aristotle was intrigued by the fact that the angle in a semi-circle is always right.
Aristotle described the conditions which are necessary if the conclusion is to hold, but did not add anything that assists with this problem. It is testified that it was from Egypt that Thales acquired the rudiments of geometry. However, the evidence is that the Egyptian skills were in orientation, measurement, and calculation. Herodotus had been told that Thales advised Croesus to divide the river into two parts.
The story is that Thales directed the digging so that the river was diverted into two smaller streams, each of which could then be forded. The story from Herodotus describes a formation similar to an oxbow lake. With both channels then being fordable, Croesus could lead his army across the Halys.
However, Herodotus did not accept that story, because he believed that bridges crossed the river at that time I. There is considerable support for the argument that Croesus and his army crossed the Halys by the bridge which already existed and travelled by the Royal Road which provided the main access to the East. Because of the vast timescale, specific details of just where or when Thales was born are sketchy. Some ancient sources name his parents as Examyes and Cleobuline.
It is possible and likely that his family was of the higher class, and perhaps even wealthy merchants. Some have traced the family of Thales back to an important Phoenician prince. It must be acknowledged, however, that it is possible that Thales was born in Athens and later migrated to Miletus. This was a school of elite philosophers known to have been established in Athens in the time period attributed to the life of Thales.
But Thales was bold enough to go beyond this way of thinking in favor of more logical and rational explanations. Sambursky writes in [ 15 ] :- It was Thales who first conceived the principle of explaining the multitude of phenomena by a small number of hypotheses for all the various manifestations of matter. Thales believed that the Earth floats on water and all things come to be from water.
For him the Earth was a flat disc floating on an infinite ocean. It has also been claimed that Thales explained earthquakes from the fact that the Earth floats on water. Again the importance of Thales' idea is that he is the first recorded person who tried to explain such phenomena by rational rather than by supernatural means. It is interesting that Thales has both stories told about his great practical skills and also about him being an unworldly dreamer.
Aristotle , for example, relates a story of how Thales used his skills to deduce that the next season's olive crop would be a very large one. He therefore bought all the olive presses and then was able to make a fortune when the bumper olive crop did indeed arrive. On the other hand Plato tells a story of how one night Thales was gazing at the sky as he walked and fell into a ditch.
A pretty servant girl lifted him out and said to him "How do you expect to understand what is going on up in the sky if you do not even see what is at your feet". As Brumbaugh says, perhaps this is the first absent-minded professor joke in the West!
The bust of Thales shown above is in the Capitoline Museum in Rome, but is not contemporary with Thales and is unlikely to bear any resemblance to him. References show. Biography in Encyclopaedia Britannica. Diogenes Laertius, Lives of eminent philosophers New York, O Neugebauer, The exact sciences in antiquity Providence, R. S Sambursky, The physical world of the Greeks London, Storia Sci. C R Fletcher, Thales - our founder? W Hartner, Eclipse periods and Thales' prediction of a solar eclipse : Historic truth and modern myth, Centaurus 14 , 60 - D Panchenko, Thales's prediction of a solar eclipse, J.
D Panchenko, Thales and the origin of theoretical reasoning, Configurations 1 3 , - Additional Resources show. Subsequently became interested in the religious vocation, thus joining the congregation of the Oratory as a novice, decision it is believed that was influenced by his character and the loss of his parents in the early s.
During the novitiate, Malebranche, concentrated on meditation and spiritual development. After a few years of taciturn life he was ordained a priest in September After being ordained, he devoted himself to the study of various topics.
Practice that was in tune with the principles of the Oratorium, a center in which the religious, in addition to focusing on their religious work, carried out various investigations related to cultural and historical issues. For this same period , he became interested in the life and work of St. Augustine , a religious on which he wrote various works. Also, he studied and interpreted the sacred texts, however, these subjects did not seem to be passionate.
When he read the Treaty of Man he became interested in all the work of the French philosopher, which he studied in detail, deeply analyzing each work. At that time, he studied mathematics, physics, and physiology. Based on this new knowledge, he analyzed the Cartesian and Augustinian works. The first book of the philosopher was The search for truth , a work in which Malebranche delves into the spirit, his relationship with the body and God, emphasizing the importance of the relationship between the spirit and God.
In this criticism of pagan and Christian philosophers, for not delving into these relationships, he also proposes as a task of philosophers to highlight the connection between God and the spirit, an idea that is linked to the occasional doctrine; a short time later he published the other two volumes of the book.
This work delved into topics such as creation, incarnation, divine grace, and human freedom. Given the theme that he dealt with, it was quickly included in the Index. At the end of the s, he wrote and published Entretiens sur la mort , a book that revolved around conversations and ideas about the death of three men, one thinks that life is too short, another that it is too long and the last more spiritual and conscious about the experiences he has had raises that death only expands our minds.
This work is based on the near-death experience the philosopher lived when he became seriously ill. A year later he published the Treatise on the Love of God , as the name implies, this treatise speaks about the love of God, emphasizing how man is drawn to love him and how this produces happiness.
Two years later, he was appointed honorary member of the French Academy of Science, for his contributions in the field of mathematics. His last work was Conversation of a Christian philosopher and a Chinese philosopher , a book in which he deals with themes such as the existence of God and the nature of it, seen from two perspectives. The renowned philosopher and religious died on October 13, , in Paris.
Philosopher, a historian, and British economist considered one of the most relevant figures of the 19th century. Mill was a brilliant and influential scholar. His thinking and the ideas he promoted changed the way in which political theories on human rights and equality were understood, throughout his career, he rejected the actions of the East India Company in the colony.
He was one of the main drivers of utilitarianism, a philosophical theory created by Jeremy Bentham, an economist with whom he worked for several years. Among his most outstanding works are Principles of political economy and Analysis of the phenomena of the human spirit Mill was the father of the renowned philosopher and utilitarian economist John Stuart Mill. In he graduated as a Presbyterian preacher, a profession he practiced on an itinerant basis. At the same time, he started teaching.
While teaching, he became interested in historical and philosophical studies, areas in which he deepened the rest of his life. Towards the beginning of the 19th century, he moved to London, where he served as a journalist. At that time, he published a booklet in which he talked about the corn trade, criticizing the reward given for the export of grain.
The following year, he began to write History of British India , a work in which he delved into the history of India based on the information collected in recent years by English-speaking writers, it consisted of three volumes divided into six books.
In the first book, he deals with the first interactions between Great Britain and India, the second book talks about religion, literature, and culture of ancient India. The third book, talks about the Islamic conquest and the government and the last three deal with the expansion and consolidation of the British government in India, emphasizing the operation of the East India Company, a company that criticized extensively.
In , he came into contact with the economist and philosopher Jeremy Bentham , with whom he shared interests and ideas, becoming allies and fellow students. In the following years Mill adopted the principles of utilitarianism, which he helped spread. He was also editor and writer of the Philanthropist newspaper with William Allen, a publication in which he contributed articles on education, laws, and freedom of the press.
During these years he promoted various reforms that changed the way the colony was governed. At the beginning of the s, he published Principles of Political Economy , a book in which he presented his theory of the salary fund, which is directly related to supplying and demand.
This was further developed by his son, John Stuart Mill. In the following years, he participated in the discussions that led to the foundation of the University of London in Four years later, he published Analysis of the phenomena of the human spirit , a work in which he applied the utilitarian premises to psychology, proposing a theory of the human mind based on the foundations of associationism.
It is necessary to highlight that his work History of British India , written without him visiting the country, created an unfavorable image of India , which was seen by readers as an extremely backward and underdeveloped country. The renowned British scholar and economist died on June 23, , in Kensington, London. Philosopher and economist, founder of the Psychic Research Society, of which he was also president. Sidgwick is one of the most prominent utilitarian philosophers of the 19th century.
The creator of the theory of international values , which he developed in his most recognized work is Principles of political economy Throughout his professional career, he worked as a professor at Trinity College and Knightbridge. In parallel, he conducted various research on ethics, morals, and economics. He was a follower of the ideas of John Stuart Mill and Immanuel Kant , which are reflected in his work.
0コメント