Claudius Ptolemy was an influential mathematician, astronomer, astrologer, geographer and also a poet. He was a Greek-Roman citizen and lived in Alexandria, Egypt. Ptolemy was famous for a number of discoveries, out of which the most famous was a theory which expounded that the earth was the center of the universe. The term “geocentric” came to being from this theory. According to him, the earth was the orbital epicenter of all the celestial bodies and that sun, moon, stars and other heavenly bodies revolved around the earth. His achievement was considered paramount during his time and quite a number of astronomers followed it religiously (especially the Greeks), until the 17th century. Later on, the works of Ptolemy evoked more controversies and arguments than any other mathematician or geographer. Many of his theories were proven to be incorrect. However, one must admit he was among the early astronomers and mathematicians who contributed a great deal to mathematics, geography and astronomy.
Most of the facts pertaining to Ptolemy’s life are shrouded in mystery and there is no definitive record regarding his date of birth. Till today, whatever little is known of him comes from his works and some other historical findings. One thing is for sure that he was Greek by birth and was a citizen of Rome and therefore the name, Claudius (Roman), Ptolemy (Greek). He lived in Egypt during a time when the Romans ruled Egypt. Moreover, he is believed to have been born in the town of Ptolemais Hermiou in Thebaid. Several efforts to find the chronicles of Ptolemy’s personal life have gone futile. Ptolemy lives only through his works. Studies reveal that he spent most his life in pursuit of knowledge.
Ptolemy’s major astrological text is the ‘Tetrabiblos Syntaxis’, meaning four books. In this book Ptolemy’s efforts to draw a more rational picture of the astrology of his days are evident. He offered a detailed framework on the subject which helped the practitioners of his time to be able to understand astrology both on scientific and religious grounds. The ‘Tetrabiblos’ is known to have "enjoyed almost the authority of a Bible among the astrological writers for a thousand years or more". It is more of an explanation on the art of astrology and the compilation of astrological beliefs which existed in the era of Ptolemy. It does not delve deep into the details of the practice of astrology. Ptolemy avoided illustrations in the book and mentioned only that information which was both reliable and believable. Basically, he wanted to prove that astronomy is not quite an abstract genre as the general conception was, by outlining its philosophical and explicable sides. The contents were gathered from earlier sources, but what Ptolemy did was he tried to make them seem more logical by putting them in an organized manner. He explained the limits of astrology in a precise manner. He was of the opinion that the circumstances in which a person was raised is more likely to determine his future deeds and even his personality is also affected more by his upbringing than the position of the stars, moon and the sun. Hence, he concluded that astrology is useful in our lives to some extent but should not regulate the course of our lives.
Ptolemy’s reputation came along with his astronomical works. He recorded over 1000 stars, of which 300 were newly found. Also, he was responsible for the formation of the first practical theory of refraction of light. He discussed about the dimensions of the planets with much precision. The ‘Almagest’, an astronomical treatise by Ptolemy is a complete text on the ancient view of astronomy. Ptolemy’s inspiration for the book was the astronomical observations recorded by his predecessors. These observations were already 800 years old when Ptolemy sat to write his book. In this he revealed his vision of the universe by studying the observations of his ancestors. The ‘Almagest’ was considered the Gospel of astronomy by his successors for many centuries throughout medieval Europe. The ancient Greeks were of the opinion that the path of the planets was completely spherical which was disproven by later discoveries which established that the orbits are elliptical. Even Ptolemy held this belief. In his manual Ptolemy clearly followed the steps of Aristotle who propounded that the planets moved in perfect circles in a continuous and uniform motion. Ptolemy’s observation described earth as a spherical object which he argued remains suspended freely in the center of the universe. The stars were fixed bodies attached to a solid exterior of the universe which lay beyond the orbit of Saturn. Most of these studies were based on Aristotle’s philosophy; however, by determining the motions of each of the planets in a detailed manner, Ptolemy offered an original contribution in the field of astronomy. The ‘Almagest’ is one of Ptolemy's early works which offers an in-depth study of the mathematical theory of the motions of the sun, moon, and other planets. He developed a theory which expounded that the planets move in circular ‘epicycles’ along their orbits. His theory was widely accepted during those days.
One of Ptolemy’s most significant works was ‘Geographia’ which consisted of eight books. This again achieved wide approval despite the distortions and shortcomings which were discovered much later. The map which he drew was inaccurate mostly, regarding the world outside the Roman Empire.
Death & Legacy
It is believed that Ptolemy died in around 168 AD. He was more than an astronomer. Till today, he is considered to be an important figure when the history of geography and cartography are recounted. Until Columbus came up with his map of the world, Ptolemy’s map was taken as the principal guide. Even the Ptolemaic view of the universe had dominated science for some centuries as Ptolemy successfully established his findings in the form of a theory and this theory actually worked. He was also able to calculate positions of the planets accurately. Most of his primary works have survived and have been subject to many speculations. Though, many of his theories were corrected in later times, yet he is still respected for his contributions to science.
- Megale Syntaxis tes Astronomias
- Tetrabiblos Syntaxis
- Phaeis aplanon asteron kai synagoge episemaseion