KNOX THEOLOGICAL SEMINARY
THE BEGINNINGS OF WESTERN SCIENCE
MODULE 6 – REFLECTIONS PAPER 2
SUBMITTED TO DR. TIMOTHY SANSBURY
IN PARTIAL FULFILLMENT OF
CC602 HISTORY OF SCIENCE (SU2022)
BY
DOUGLAS ROTHAUSER
AUGUST 13, 2022
WORD COUNT: 593
I could not have understood how and why the practice of astrology was so highly respected in Christendom during the Middle Ages without first examining the medieval criteria of rationality contained in their worldview. For without that examination, we might make the mistake of judging astrological theory through the lens of modern sensibilities, not recognizing that in medieval times, astrologers were serious scholars who were passionately interested in cosmic physics and its effects.
For the medievals, astrology was the holistic study of the heavens and their influence in the terrestrial realm, and they used it to determine what was rational, real, regular, and good1. For them, astrology provided these benefits in two ways. First, it provided a set of rational beliefs about the physical influence within the cosmos known as “natural astrology.” Second, based on the causal power observed via natural astrology, there was “judicial astrology,” which sought to forecast events through the calculation of the planetary and stellar bodies and their relationship to the earth. Therefore, through the evidence they had available to them at the time, it was not unreasonable that they considered astrology a legitimate area of study.
Regarding natural astrology, there were many sensible reasons to think that the heavenly spheres significantly influenced the sublunar realm. For example, Ptolemaic astronomy provided a system for explaining regular celestial motion showing that heavenly spheres move according to their nature in divinely ordained perfect circles. Also, there was no doubt that the heavens generated light and heat for the earth and that the seasons were clearly related to solar motion around the ecliptic2. Furthermore, the motion of the tides could be correlated with the motion of the moon and concomitantly with the sun.3 From these criteria, the medievals reasonably abduced terrestrial effects from celestial causes.
If according to natural astrology, the heavens exert such a strong influence on earthly elements, it would not be unreasonable for the medieval natural philosopher to postulate that they also have the causal power to influence the lives of human beings and future historical events4. It is judiciary astrology that seeks to address these concerns. The practice of judicial astrology involves the casting of horoscopes not only to predict the fate and acts of individuals but those of nations as well. It is in this dimension of astrology that many theologians of the church took issue. For example, Augustine protested that if the position of stars and planets determines men’s destinies, human free will and responsibility are negated5. Ultimately, the root of the issue with judiciary astrology was that it assigned divine status to the stars and planets, making them the causal agents of all that comes to pass. In the final analysis, it was deterministic, and it undermined God’s sovereignty.
Though astrological determinism was strongly denounced as anathema (e.g., Condemnation of 1277) and astrologers were considered charlatans, many Christian scholars admitted that natural astrology was useful in the areas of health, illness, storm, calm, productivity, and unproductivity6.
In summary, we might be tempted to look down our noses with chronological snobbery upon medieval scholars for their credulity about astrology. However, they came to their beliefs honestly through the best that natural philosophy had to offer in those centuries. Therefore, we should be sympathetic to their conclusions as well as humbled by how much they came to know without the tools of scientific investigation we employ today. Furthermore, we can appreciate the judgment of Christian theologians who rightly recognized the heretical nature of judiciary astrology.
Lindberg, David C. The Beginnings of Western Science. Chicago: University of Chicago Press, 2007.
Sansbury, Timothy. Module 1 Reading and Video Lectures, Lesson 05. February 1, 2021. https://learn.knoxseminary.edu/mod/page/view.php?id=41485 (accessed June 26, 2022).
—. Module 4 Reading and Video Lectures, Lesson 14. February 1, 2021. https://learn.knoxseminary.edu/mod/page/view.php?id=41499 (accessed August 11, 2022).
Sansbury, Timothy. Module 1 Reading and Video Lectures, Lesson 05. February 1, 2021. https://learn.knoxseminary.edu/mod/page/view.php?id=41485 (accessed June 26, 2022).↩︎
Lindberg, David C., The Beginnings of Western Science (Chicago: University of Chicago Press, 2007),271.↩︎
Note that it was important for the sailing industry to accurately predict the motion of the tides to plan their courses safely. (Sansbury, Module 4 Reading and Video Lectures, Lesson 14 2021)↩︎
Ptolemy, in his Tetrabiblos, defends astrology making the point that if the power from the eternal ethereal substance that permeates the whole earth has such a great influence on terrestrial phenomena, it also has the same power to influence individual human beings. (Lindberg 2007, 272)↩︎
Lindberg, David C., The Beginnings of Western Science (Chicago: University of Chicago Press, 2007),273-274.↩︎
Hugh of St. Victor (d. 1141) and Nicole Oresme (d. 1382) believed in the usefulness of natural astrology while at the same time denouncing judiciary astrology (Lindberg 2007, 274-276). Later in the sixteenth century, even Calvin affirmed natural astrology in general in that he believed that God influences the world by the stars (Sansbury, Module 4 Reading and Video Lectures, Lesson 14 2021).↩︎