Early Life (Great Lives from History: The Ancient World, Prehistory-476)
Very little is known about the life of Ptolemy (TOL-uh-mee). He was born in Egypt at the end of the first century c.e., but his birth date and birth place and his life thereafter are subjects of speculation. It is thought that he might have been born in the Grecian city of Ptolemais Hermii in Upper Egypt and that he might have lived to the age of seventy-eight. It has been suggested that he studied and made astronomical observations, staying for more than half of his life among the elevated terraces at the temple of Serapis in Canopus near Alexandria, where pillars were erected with the results of his astronomical discoveries engraved on them. He was probably the descendant of Greek or Hellenized ancestors and obtained Roman citizenship as a legacy from them.
Much more is known about the age in which Ptolemy lived. It was a century during which Rome ruled the Mediterranean world and during which four successive Roman emperors, Trajan, Hadrian, Antoninus Pius, and Marcus Aurelius, built roads and bridges, opened libraries and colleges, and maintained Rome’s power and peace. It was a time when educated men spoke Greek as well as Latin, when Athens was still honored for its cultural traditions, when Marcus Aurelius wrote his Tōn eis heauton (c. 171-180; Meditations, 1634) in Greek, and Greek was still the language of science and the arts.
Ptolemy, who probably used the libraries at Alexandria, was strongly influenced by a...
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Life’s Work (Great Lives from History: The Ancient World, Prehistory-476)
Some historians maintain that Ptolemy merely plagiarized from Hipparchus; others have said that Ptolemy superseded Hipparchus and made the work of the earlier scientist superfluous. In fact, it could be said that Ptolemy immortalized Hipparchus by acknowledging the debt he owed to his distant predecessor and by frequently quoting from him.
Whatever historical assessment is more correct, there is no doubt that Ptolemy’s work in astronomy alone lasted for more than fourteen hundred years, until the great scientific achievements of Nicolaus Copernicus (1473-1543) and Johannes Kepler (1571-1630). Ptolemy used new instruments or improved on old ones to make his observations. In the Mathēmatikē syntaxis (c. 150 c.e.; Almagest, 1948), one of his most significant books, he utilized the mathematical methods of trigonometry to prove that Earth was a sphere and went on to postulate that the heavens were also spheres and moved around an immobile Earth in the center of the solar system. He dealt with the length of the months and the year and the motion of the sun; he covered the theory of the moon; and he figured out the distance of the sun, and the order and distances of the planets, from Earth. Much of this was not new, not original; the Almagest was essentially a restatement of astronomical knowledge available three hundred years earlier. Yet Ptolemy was able to synthesize that scientific information into a system and to expound it in...
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Significance (Great Lives from History: The Ancient World, Prehistory-476)
It would be unreasonable to expect great scientific breakthroughs during the second century c.e., and they did not happen. What did occur was the gradual advancement of knowledge to which Ptolemy contributed. Not only did Ptolemy write the Almagest and the Geography, adding new and significant materials to those of his predecessors, but he also attempted to illuminate the science of optics and the art of music. In the first case, although little was known about the anatomical and physiological structure of the eye, he devised a table of refraction, and his book reveals that he understood that a ray of light deviates when it passes from one medium into another of a different density. He addressed the role of light and color in vision, with various kinds of optical illusions and with reflection. Ptolemy’s volume on music theory, known as the Harmonika (second century c.e.; Harmonics, 2000), covers the mathematical intervals between notes and their classification. He propounded a theory that steered a middle ground between mathematical calculations and the evidence of the ear. Observation was again a guiding principle of his art as well as his science.
Other work on mechanics, dimensions, and the elements was done but has not survived. What did survive had great influence on the Arabic science of astronomy, led to the rise of European astronomy, and influenced the work of Copernicus himself in the fifteenth century. The...
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Further Reading (Great Lives from History: The Ancient World, Prehistory-476)
Barker, Andrew. Scientific Method in Ptolemy’s “Harmonics.” New York: Cambridge University Press, 2001. This study illuminates not only the Harmonics but also Ptolemy’s observational methods in general.
Grasshoff, Gerd. The History of Ptolemy’s Star Catalog. New York: Springer-Verlag, 1989. A careful study of the relationship between Ptolemy’s work and that of Hipparchus, showing that charges of plagiarism are anachronistic and based in a misunderstanding of Ptolemy’s scientific objectives.
Irby-Massie, Georgia L., and Paul T. Keyser. Greek Science of the Hellenistic Era: A Sourcebook. New York: Routledge, 2001. Chapters cover the main scientific disciplines in the Hellenistic era, providing a historical and scientific context for Ptolemy’s work in many fields.
Ptolemy. Harmonics: Translation and Commentary. Translated by Jon Solomon. New York: Brill Academic Publishers, 2000.
Ptolemy. Ptolemy’s “Almagest.” Translated by G. J. Toomer. 1984. Reprint. Princeton, N.J.: Princeton University Press, 1998.
Ptolemy. Ptolemy’s “Geography.” Translated by Alexander Jones and J. Lennart Berggren. Princeton, N.J.: Princeton University Press, 2000.
Ptolemy. Tetrabiblos. Translated by F. R. Robbins. Loeb Library. Cambridge, Mass.: Harvard University Press, 1980. For students and readers who may want to sample the...
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