| From: Thomas Hockey et al. (eds.). The Biographical Encyclopedia of Astronomers, Springer Reference. New York: Springer, 2007, pp. 553-555 |
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Ibn ʿEzra: Abraham
ibn ʿEzra
Tamar M. Rudavsky
Died Rome, (Italy),
or possibly Palestine, circa 1167
Abraham
ibn ʿEzra was a poet, grammarian,
biblical exegete, philosopher, astronomer, astrologer, and physician. He lived
in Spain until 1140 and then left Spain for a period of extensive wandering
in Lucca, Mantua, Verona, Provence, London, Narbonne, and finally Rome. It
was during the latter period that most of his works were composed. His wanderings
forced him to write in Hebrew as well as in Latin, a fact that perhaps saved
his works from oblivion. Like his teacher Abū al‐Barakāt,
his son Isaac converted to Islam.
Ibn
ʿEzra
is best known for his biblical commentaries, which are written in an elegant
Hebrew, replete with puns and word plans. These commentaries were commenced
in Rome when he was already 64. Ibn ʿEzra
was the first Jewish author to interpret a significant number of biblical
events in an astrological way and to explain certain commandments as defenses
against the pernicious influence of the stars.
Because
of his constantly alluding to “secrets” in these commentaries based on astrological
doctrines, Ibn ʿEzra's works inspired
numerous supercommentaries. Ibn ʿEzra
himself claimed that only the individual schooled in astrology, astronomy,
or mathematics would understand these commentaries properly. Perhaps the most
famous commentator upon Ibn ʿEzra was
Spinoza, who adduced “Aben Ezra, a man of enlightened intelligence and no
small learning,” in support of his own contention that Moses could not have
written the Pentateuch. Although Ibn ʿEzra
did not write any specifically philosophical works, he was strongly influenced
by the Jewish Neoplatonist philosopher Solomon ibn Gabirol, and his works
contain much Neoplatonic material.
Although
Ibn ʿEzra was one of the
foremost transmitters of Arabic scientific knowledge to the West, most of
his scientific works are extant in manuscript only. Interestingly, most of
his works appear in two or more versions; most scholars agree that in as much
as Ibn ʿEzra
was an itinerant scholar wandering from city to city, he would write new versions
for each group of patrons he encountered.
The first
group of treatises is devoted to teaching skills related primarily to astronomy
and mathematics, as well as the use of scientific tools and instruments. The
major works in this group are Sefer ha‐mispar (The book of the
number), designed to be a basic textbook in mathematics; Sefer taʿamei
ha‐luhot (The book of the reasons behind the astronomical tables),
a treatise written in four different versions (two in Hebrew and two in Latin)
to provide astronomical and astrological knowledge to persons interested in
using astronomical tables; Keli ha‐nehoshet (The instrument of
brass, i. e., the astrolabe), a technical manual, written in three
different Hebrew versions as well as a Latin version, designed to teach the
astronomical and astrological uses of the astrolabe; Sefer ha‐ʿibbur (The book of intercalation),
written in two versions, designed to establish the Jewish calendar and explain
its fundamentals; and, finally, Sefer ha‐ʾehad (The book
on the unit), a short mathematical treatise devoted to the attributes of the
numbers.
The second
group of treatises comprises astrological works exclusively and includes both
astrological textbooks and a series of astrological works that deal with the
various branches of astrology. In addition to these treatises, Ibn ʿEzra translated into
Hebrew a no longer extant Arabic scientific treatise, Ibn al‐Muthannā's
Commentary on the Astronomical Tables of al‐Khwārizmī.
This work includes Ibn ʿEzra's
introductory assessment of the transmission of Hindu and Greek astronomy to
the Arabic sciences.
Because
Ibn ʿEzra was one of the
first Hebrew scholars to write on scientific subjects in Hebrew, he had to
invent many Hebrew terms to represent the technical terminology of Arabic.
For example, he introduced terms for the center of a circle, for the sine,
and for the diagonal of a rectangle. He describes his own research as hakmei
ha‐mazzalot (science of the zodiacal signs), a term he uses often
to refer to a number of branches of science: astrology, mathematics, astronomy,
and the regulation of the calendar. In as much as the purpose of these works
was primarily to educate and introduce scientific findings to a lay audience,
they serve as an excellent source of learning about scientific texts available
in 12th‐century Spain.
As noted
by Shlomo Sela, one of Ibn ʿEzra's main aims was
to “convey the basic features of Ptolemaic science, astronomical as well as
astrological, as it was transformed by the Arabic sciences, especially in
al‐Andalus” (Sela, 2000, p. 168). Thus, for example, his best‐known
work, Beginning of Wisdom, functions as an introductory astrological
textbook and deals with the zodiacal constellations and planets, their astrological
characteristics, and more technical aspects of astrology. Ibn ʿEzra's
star list appears as a section of his work The Astrolabe. The list
is given in the form of a paragraph, in which the coordinates are given in
Hebrew alphabetic numerals, and the Arabic names are transliterated into Hebrew
characters. As Bernard Goldstein has pointed out, many of the discrepancies
between Ibn ʿEzra's
star positions and those in the Greek text of the Almagest can be traced
to the Arabic versions of the Almagest. In his translation of Ibn al‐Muthannā's
Commentary, Ibn ʿEzra describes the
early stages of astronomy among the Arabs, listing a number of prominent astronomers
whose works he consulted. The Hebrew versions of Ibn al‐Muthannā's
commentary have been useful for interpreting a set of canons for tables with
Toledo as the meridian preserved in a Latin manuscript.
According to John North, Abraham ibn ʿEzra was the earliest scholar to record one of the seven methods for
the setting up of the astrological houses. This method was used, for example,
by Gersonides who made use of Ibn
ʿEzra's Book of the World in his prognostication of 1345.
In as much
as Abraham Ibn ʿEzra's works were
widely copied in Hebrew and translated into European languages, he was responsible
for the availability of much Arabic science in Hebrew and Latin, and he helped
to spread the new Hebrew astronomical literature throughout Europe.
Selected References
Friedlander,
M. (1877). Essays on the Writings of ibn Ezra.
London. (Reprint, Jerusalem, 1944.)
Goldstein, Bernard
R. (1967). Ibn al‐Muthannā's Commentary on the Astronomical
Tables of al‐Khwārizmī. Two Hebrew versions, edited and
translated, with an astronomical commentary by Bernard R. Goldstein. New Haven:
Yale University Press.
——— (1985). “Star
Lists in Hebrew.” Centaurus 28: 185–208.
——— (1996). “Astronomy
and Astrology in the Works of Abraham ibn Ezra.” Arabic Sciences and Philosophy
6: 9–21.
Halbronn,
Jacques (1966). “Le diptyque astrologique d'Abraham Ibn Ezra et les cycles
planétaires du Liber Rationum.” Revue des études juives 155: 171–184.
Ibn
ʿEzra,
Abraham (1845). Keli haNehoshet, edited by H. Edelman. Königsberg.
——— (1874). Sefer
haʿIbbur,
edited by S. Z. H. Halberstam. Lyck.
——— (1895). Sefer
haMispar, Das Buch der Zahl, edited by Moritz Silberberg. Frankfurt
am Main.
——— (1939). Sefer
haMivharim, edited by Judah Loeb Fleischer. Jerusalem.
——— (1951). Sefer
ha‐Teʾamim, edited by Judah Loeb Fleischer. Jerusalem.
——— (1971). “Sefer
haʿOlam.” In Sefer Mishpetei haKokhavim,
edited by Meʾir Yshaz Bakʾal, pp. 36–54. Jerusalem.
——— (1985). “Sefer
Yesod Mora ve‐Yesod Torah.” In Yalqut Abraham ibn Ezra. New York.
——— (1988). Ibn
Ezra's Commentary on the Pentateuch. (Translated by H. Norman Strickman
and Arthur M. Silver. New York: Menorah Pub. Co.)
Langermann, Y. Tzvi (1993). “Some Astrological Themes in the
Thought of Abraham ibn Ezra.” In Rabbi Abraham ibn Ezra: Studies in the
Writings of a Twelfth‐Century Jewish Polymath, edited by Isadore
Twersky and Jay M. Harris, pp. 28–85. Cambridge Massachusetts: Harvard University
Press.
——— (2000). “Hebrew
Astronomy: Deep Soundings from a Rich Tradition.” In Astronomy Across Cultures,
edited by Helaine Selin, pp. 555–584. Dordrecht: Kluwer.
Levy, Raphael (ed.
and trans.) (1927). The Astrological Works of Abraham ibn Ezra: A Literary
and Linguistic Study with Special Reference to the Old French Translation
of Hagin. Baltimore: Johns Hopkins University Press.
Levy, Raphael and
F. Cantera (eds. and trans.) (1939). The Beginning of Wisdom, An Astrological
Treatise by Abraham ibn Ezra. Baltimore: Johns Hopkins University Press.
Millás
Vallicrosa, José María (1947). El libro de los fundamentos de las Tables
astronómicas de R. Abraham ibn Ezra. Madrid:
Consejo Superior de Investigaciones Científicas.
North, John D. (1986).
Horoscopes and History. London: Warburg Institute.
Sela, Shlomo (1997). “Scientific Data in the Exegetical‐Theological
Work of Abraham Ibn Ezra: Historical Time and Geographical Space Conception”
(in Hebrew). Ph.D. diss., Tel Aviv University.
——— (1999). Astrology
and Biblical Exegesis in the Thought of Abraham Ibn Ezra (in Hebrew).
Ramat‐Gan.
——— (2000). “Encyclopedic
Aspects of Abraham Ibn Ezra's Scientific Corpus.” In The Medieval Hebrew
Encyclopedia of Science and Philosophy, edited by S. Harvey, pp. 154–170.
Dordrecht: Kluwer.
——— (2001). “Abraham ibn Ezra's Scientific Corpus–Basic Constituents
and General Characterization.” Arabic Sciences and Philosophy 11: 91–149.
(Sela has managed to ascertain the existence of 26 different treatises, representing
14 distinct treatises in all, written mostly in Hebrew and partly in Latin.)