This document discusses several issues related to understanding Copernicus' influence on Jewish thought and culture: 1. There is no evidence that Copernicanism was directly "appropriated" by Jews, but many Jewish thinkers had a deep interest in theoretical astronomy as a real issue. 2. Jewish astronomers and philosophers, like their non-Jewish counterparts, recognized the sun's role in planetary motions even before Copernicus, showing astronomy was an important topic. 3. Significant population movements of educated Jews across Europe and between Europe, the Middle East, and North Africa could have facilitated the transmission and spread of scientific ideas like Copernicanism.

1. WHY IS COPERNICUS INTERESTING
FOR THE HISTORIAN OF JEWISH
THOUGHT AND CULTURE?
One historian’s search for “real” issues.

2. 1 Issues of Reception
• No room for apologetics!
• No “appropriation” of Copernicanism in the
sense that I understand the term.
• Is there a typical reaction?

5. ‫נקרא‬ ‫אשר‬ ‫עולם‬ ‫מהבנין‬ ‫אחר‬ ‫ציור‬ ‫קופערניקוס‬ ‫הגדול‬ ‫התוכן‬ ‫המציא‬ ‫זה‬ ‫בזמננו‬ ‫והנה‬
‫אין‬ ‫אבל‬ ‫מספר‬ ‫לאין‬ ‫עד‬ ‫רבים‬ ‫באמת‬ ‫הם‬ ‫החדש‬ ‫מהבנין‬ ‫היוצאת‬ ‫חדשה...והתועלת‬ ‫תכונה‬
‫היומי‬ ‫גלגל‬ ‫שיש‬ ‫לומר‬ ‫צריכין‬ ‫אנו‬ ‫שאין‬ ‫הוא‬ ‫הכללית‬ ‫התועלת‬ ‫רק‬ ‫כולם‬ ‫לפרשם‬ ‫מקום‬ ‫כאן‬
‫אי‬ ‫הזה‬ ‫המהירות‬ ‫כי‬ ‫עמו‬ ‫הכוכבים‬ ‫כל‬ ‫ומכריח‬ ‫למערב‬ ‫ממזרח‬ ‫רב‬ ‫במהירות‬ ‫המתנועע‬
‫שעות‬ ‫בכ"ד‬ ‫הארץ‬ ‫סביב‬ ‫ויתנועע‬ ‫גדול‬ ‫היותר‬ ‫הכוכב‬ ‫הוא‬ ‫השמש‬ ‫כאשר‬ ‫בשכל‬ ‫לצייר‬ ‫אפשר‬
‫זו‬ ‫בחכמה‬ ‫למתחיל‬ ‫בזה‬ ‫ודי‬ ‫הכוכבים‬ ‫שאר‬ ‫וכן‬ ‫גדול‬ ‫היקף‬ ‫כך‬ ‫כל‬
In our own time the great astronomer Copernicus came up with a
different conception of the world-structure, which is known as “the new
configuration”… The advantages of the new structure are indeed many,
even innumerable, but this is not the place to explain them all; just the
general advantage, which is that we don’t need to say that the sphere of
daily motion moves from east to west with great velocity, forcing all of the
stars along with it. Indeed, such a velocity is inconceivable, given that
the sun is the largest star, yet makes such a great circuit around the
earth in 24 hours, and so also the rest of the stars. This is enough for a
beginner in this science.

7. 2 “Background” Issues
It was obvious to astronomers in antiquity
and the medieval period that the sun plays
a role in the motions of all of the planets—
even if this fact is not a part of the
“Ptolemaic system”.
Many Jewish thinkers of varying background
and tendencies took a deep interest in
theoretical astronomy—it was a “real
issue” for them.

8. Let N be an integer number of tropical
years, R an integer number of planetary
circuits in longitude, and A an integer
number of synodic periods. Then, for the
outer planets, N=R + A. Good numerical
approximations were already known in
early Babylonian astronomy.
Otto Neugebauer, HAMA, I, 150-151.

9. From an anonymous, incomplete, unpublished medieval
Hebrew philosophical text:
‫אחד‬ ‫כל‬ ‫מהלך‬ ‫הנה‬ ‫כי‬ ‫כמהלכו‬ ‫מהלכם‬ ‫שלמות‬ ‫גם‬
‫ומהלך‬ ‫היוצא‬ ‫מגלגלו‬ ‫המחובר‬ ‫העליונים‬ ‫כוכבים‬ '‫מג‬
‫השמש‬ ‫למהלך‬ ‫שוה‬ ‫הקפתו‬ ‫גלגל‬…
their full motion is like its [the sun’s],
because the motion of each of the three
superior planets, which is the sum of its
motion in the epicycle and in its own orb,
is equal to the motion of the sun…

10. 3 Transmission, Migration, and
other Modes of Cultural Transfer
• Massive movement eastward of educated
Jews from Iberian peninsula to Italy, the
Ottoman Realms (and back to Italy)
• Movement back and forth between Poland
and Italy
• Constantinople—Venice axis,
Constatinople—Venice—Crete triangle

11. To look at Islamic civilization as a transmitter of science is
to view it from a point outside it…herein, precisely, is the
danger that lurks for the Islamist who allows his own
choice of research problems to be unduly determined by
facts of transmission, however important these may be…
the hypothesis seemed plausible that Copernicus might
have been influenced by his Islamic predecessors…
But what about the significance of the new models for the
history of Islamic astronomy itself? What do we learn
from them about the scientific outlook motivation of
Islamic astronomers?
A.I. Sabra, “The Appropriation and Subsequent Naturalization of Greek
Science in Medieval Islam.”

13. Yitzhak ben Shmuel AbÙ-l-Khayr