Augustine — further railed against astrology in his influential treatise City of God, and astrology gradually disappeared from Western Europe until the Middle Ages. Medieval Arabic and Jewish Astrology During its decline in the West, astrology was preserved by Arabic schools in the Middle East and in Spain with the rise of Islam in the seventh century and the conquering of Spain by the Moors. Using Ptolemy's. Almagest as a guide, Arab astronomers and astrologers created observatories and refined tables of naked-eye star observations and charts with a high degree of precision and accuracy.
Ulugh Beg's — observatory was built in Samarkland in central Asia, and his work there lead to the creation of a table of 1, stars.
The Toledan Star Tables, prepared by Moorish astronomer al-Zarqali — , became the model for the Alfonsine Tables, which were translated and prepared under the sponsorship of Spanish King Alfonso X — and became the standard charts for astrologers and astronomers. Jewish medieval thinkers such as the twelfth-century polymath Rabbi Abraham Ibn Ezra — also combined cabbalistic studies with astronomical knowledge to produce treatises of astrology. Ibn Ezra's works reveal an attitude towards astrology in Judaism that was more liberal than it was in Christianity.
Many early thinkers asserted that astrology and religion did not conflict. With the recovery of the works of ancient Greek philosophers and the creation of medieval universities in the twelfth century, the study of astronomy and astrology experienced a revival in Western Europe. Theologians were especially careful to condemn forms of astrology that were incompatible with the Catholic Church's doctrines—especially the tenet that people are free to choose the Christian life.
Rather, from the twelfth century onwards, theologians accepted the Ptolemaic form of astrology in which astrological influences were only probable, as well as subject to the inscrutable will of God. The Aristotelian teaching that the processes of earthly change depended upon the stellar spheres, however, was accepted by church scholars like Thomas Aquinas c.
The division between fatalistic judicial astrology and probable natural astrology continued in fourteenth- and fifteenth-century texts. Astrology as a set of beliefs about physical influences in the cosmos was permissible, but astrology as the art of casting horoscopes or determining propitious moments continued to be a source of controversy. The most influential text attacking astrology was Italian philosopher Pico della Mirandola's — Disputations against Divinatory Astrology, published in , which condemned the denial of free will that Mirandola saw in current astrological practice.
Despite these growing attacks on judicial astrology, astrology continued to be practiced. Medieval and early modern physicians had to be proficient in astrology to bleed and make diagnoses. Court astronomers were also astrologers, predicting the course of events for their rulers and publishing them in official almanacs. The invention of the printing press in the fifteenth century saw the widespread publication of ephemeris tables, which were tables of data that delineated planetary positions necessary for astrological prediction.
The great conjunction of Saturn and Jupiter in a conjunction is two or more planets situated closely together, generally within an orb of eight degrees was widely publicized, and some continental scholars saw it and other conjunctions as explanations for universal historical events.
Popular astrological works consisted largely of phlebotomy advice, or leechdoms under which astrological sign to undergo a course of bloodletting via leeches or trepanning drilling a hole in the skull to expel bad humors—as well as weather predictions. Often these texts contained interrogations and elections derived from Arabic astrology.
Interrogations were rules guiding astrologers, which answered certain questions, such as those concerning the discovery of a thief, a lost treasure, or the wealth of a prospective bride. Elections determined the propitious moment for undertaking any act of daily life, such as the start of a journey, or the commencing of a business deal.
Beginning in the sixteenth century, particularly in Protestant universities, some scholars believed astrology should be a major scholarly discipline. Scholars tried to establish astrology as a science and as a means of connecting nature and religion. Rigorous study of the astronomy and astrology was thought to provide insight into God's will. Though this more extreme connection between providence and the stars was unique to Germany, the idea that astrology could reveal universal laws, whether divine or scientific, would persevere into the seventeenth century.
It was also in Germany where doubts about astrology's legitimacy were leading to its separation from astronomy. Kepler found himself in sympathy with most of Mirandola's arguments against astrology. Kepler agreed with Mirandola's assertion that the zodiac signs were human inventions, eclipses portended nothing, and that most of astrology was worthless.
Kepler's attitude about aspects was also one he shared with his contemporary John Dee — , astrologer to Queen Elizabeth I of England — In Dee's work Propaedumata Aphoristica, he was devoted to the use of giant lenses to focus planetary aspects for good or for ill. What accounted for Kepler's mixed attitude towards astrology? First, Kepler was an avowed Copernican; in Copernicus published his Revolutions of the Heavenly Spheres, which postulated a sun-centered universe, in direct opposition to Aristotle and Ptolemy's geocentricism.
In the Aristotelian system upon which astrology was based, Earth was still because it was made of the heavy earth element, and the planets revolved around Earth because they were thought to be made of a substance called ether, whose natural motion was said to be circular.
Kepler's discovery of the three planetary laws demonstrated planetary orbits were elliptical, not circular. Since most astrology was based on Ptolemy's geocentrism, Kepler's discoveries, which contradicted Ptolemy's views, led to Kepler's doubts about their legitimacy. In addition, if Earth moved with the other planets around the sun, then all of the planets would seem to be made of the same substances as Earth, not of an ether that propelled circular motion.
So, what indeed made the planets move? This was a question that Kepler tried to answer with an appeal to astrology, proposing that planets had some sort of souls or intelligences or that there was a single moving soul in the sun that impelled all the planetary bodies. He subsequently rejected the idea of a soul for one of physical force, speculating that magnetism might be the source of planetary motion. Kepler concluded that while physical forces operated in astronomy, souls operated in astrology.
Although astrology and astronomy were clearly separated in Kepler's mind, he did not reject astrology wholesale. Kepler's growing skepticism about astrology influenced that of natural philosophers an early modern term that includes philosophers and scientists in the seventeenth century.
Most natural philosophers thought that there. However, judicial astrology was considered fraudulent. In particular, telescopic discoveries in by the Italian astronomer Galileo Galilei — revealed unseen celestial bodies, such as Jupiter's moons, that had not previously figured into astrological predictions, which led to questions about judicial astrology's validity.
Astrology, particularly natural astrology, was subjected to scientific testing in the seventeenth century, a process made easier by the formation of the first scientific societies, such as the Royal Society in London. Francis Bacon — , the English politician and philosophical founder of the Royal Society , was interested in testing the effects of solar and lunar planetary emanations because of their influence on Earth's seasons and tides.
Most of Bacon's assumptions about solar and lunar effects were similar to the principles outlined by Ptolemy in the Tetrabiblos. Robert Boyle — , the discoverer of Boyle's law, which related air volume and pressure, was also keenly interested in atmospheric composition. In his treatises, Boyle posited that the atmosphere was full of planetary emanations that may have had effects on chemical reactions, plant growth, or weather. Systematic empirical investigation of natural astrology, however, failed to reveal any lasting results.
Judicial astrology was also more politicized and popularized in the seventeenth century, a process which led to its downfall. In England, astrological almanacs predicting weather, health, and political events increased in popularity due to cheaper printing costs and increasing literacy. By London astrologer William Lilly's — political almanacs alone were selling nearly 30, a year.
The readers of these almanacs could also cast their own charts by using the astrological tables they provided. The seventeenth century, sometimes known as the Age of Iron, was a time of often brutal warfare in which post-Reformation religious and political motivations were intertwined. Almanacs thus became a means of understanding or accepting these calamitous events for the general public.
With the increasing popularity of almanacs, astrologers' erroneous predictions also became more public. If an astrologer gave a false horoscope to anticipate what his readers wanted and his prediction was wrong, the entire profession was affected. The use of the self-fulfilling prophecy was also exposed in popular publications. If an astrologer predicted a famine in the almanacs, farmers would hoard crops that led to the scarcity predicted, exposing the astrologers to more public criticism.
Censorship of the press in England may also have played a role in astrology's decline, allowing astrologers to take credit for unpublished predictions prior to the end of government censorship in Astrologers would often assert that they had predicted events such as the Great Fire of London but were censored. Without this excuse, their inability to predict future events was revealed. By the end of the seventeenth century, astrology had largely ceased to be reputable among the educated, though almanacs still survived.
Some of the decline of astrology had to do with the sheer power of discoveries in astronomy and physics. After the publication of English physicist Sir Isaac Newton 's — Principia in , it was clear that the planets acted in accordance with the same physical laws as Earth and their emanations were gravitational, not astrological. The demonstration by English astronomer Edmund Halley — that comets were higher than the moon and could return in a predictable cycle undermined comets' roles as astrological harbingers of doom.
For a variety of scientific and socio-cultural factors, astrology became a pseudoscience. The planets were now studied by astronomers and astronomy emerged as a mature scientific discipline.
Astrology today is predominantly a socio-cultural phenomenon that scantly resembles the astronomy-astrology of the past. Some critics claim that astrology is merely for entertainment, and the vague—and often universally applicable—messages in a horoscope are harmless. Others, such as British evolutionary biologist and science writer Richard Dawkins — , assert that modern astrological pseudoscience is an enemy of science because popular astrology preys upon and promotes ignorance of scientific principles.
In the ancient world, while the emphasis on the supernatural qualities of astrology continued to develop and influence the affairs of society on the lowest and highest strata, there evolved a fusion with astronomical precision that resulted in a scientific astrology wherein the accurate measurement of celestial spheres was seen as a requisite of accurate prediction. Following the death of Alexander the Great — BC , who spread the Greek philosophical tradition and intellectual culture across much of the known world, astrology began to take on an emphasis in Greek society that soon overshadowed pure astronomical observation.
Influenced by Eastern traditions, a more mundane form of everyday astrology became commonplace in Greek society, and later in Roman civilization. No longer regulated to the prediction of grand affairs of state or religion, astrology became used by Stoics as a practical medicinal art.
Good evidence of this everyday application of astrology is found in surviving Greek poems and plays that provide evidence that the positions of the planets was used as a guide to ordinary affairs. Although there was often an emphasis on the influence of the supernatural upon ancient societies, this masks real achievements that resulted from an increased emphasis upon astronomical observations.
Notable among such observations and calculations are Aristotle's observations of eclipses that argued for a spherical Earth; Aristarchus of Samos ' heliocentric model, which proposed that the Earth rotated around the sun; and Eratosthenes of Cyrene 's — BC accurate measure of the circumference of Earth.
Stimulated by astrological mythology, in BC, Euxodus of Cnidus c. Moreover, these advances in astronomy laid a foundational base for the scientific development of astronomy. Hipparchus's classifications of magnitude of brightness, for example, are still a part of the modern astronomical lexicon.
The Algamest, written in the second century AD by Ptolemy, was the most long-lasting and influential work of the scientific astrology produced in the ancient classical world. Ptolemy's errant models of an Earth-centered universe composed of concentric crystalline spheres were destined to dominate the Western intellectual tradition for more than a millennium.
In , he was accused of practicing "astral determinism" on his wealthy clients. Also in , he published a short work that included an astrological delineation of Jupiter in the Midheaven of Cosimo de Medici's horoscope. In , he drew up charts for his daughters. What he saw must have caused some consternation, for he then placed the daughters in a monastery for life. It turns out that one of the major characters in the dialogue was, in real life, a friend of Galileo's who would consult with him about primary directions.
The last horoscope cast by Galileo is dated , when he was Finally, the contents of Galileo's library reveal 14 books on astrology and many others on occult philosophy. His copy of Ptolemy's Tetrabiblos was apparently annotated, but has unfortunately been lost.
Which of the following statements describe a characteristic of the solar system that is explained by Kepler's first law? Kepler's second law states that as a planet orbits the Sun, it sweeps out equal areas in equal times. Which of the following statements describe a characteristic. 3) Suppose the planet Uranus were much brighter in the sky, so that it was as easily .. 12) Astronomy and astrology were often practiced together in ancient.
So much for the "Mister Clean" of modern science. Kollerstrom notes in his book, Interface, that Kepler himself cited this time of birth. Kepler is a great embarrassment to the scientific community, though they cover this up with smoke and mirrors. There is no denying that this great scientist - the man who gave Newton the clues he needed - not only practiced astrology, he liked it. In fact, Kepler's motivations were so cosmologically astrological that historians paint him as having one foot in the Middle Ages and one foot in the modern world.