## 1. Biography



We have only a few scant clues of his biography, and we cannot be sure
of their veracity, especially in the issue of the date of his death.
We know that he lived the first half of his life in Egypt, before
moving to Karouan, Tunisia between the years of 905-907. Most
biographers agree that he lived to the age of 100, though they
disagree on the years of birth and death. Sacid al-Andalusi
(mid-11th century), in his work *Kitab Tabakat
al-Umam,* indicates that he died in 932 (R. Blachere 1935, p.
157). However, one of Israeli's pupils, Ibn al-Jazzar died in
1009 at an approximate age of 80. If Israeli had died in 932, Ibn
al-Jazzar would have been only five years old at his death, thus this
date is unlikely. Abraham Ibn Hasday, a translator of Israeli's
works from Arabic into Hebrew, provides the date of his passing as
942. But Altmann and Stern (*Isaac Israeli*, p. xx) have
pointed out that Ibn Hasday likely made a transcription error in his
quotation of Sacid al-Andalusi. Another student of Israeli,
Dunash Ibn Tamim, wrote a commentary on the Jewish mystical work
*Sefer Yetzirah* in 956, and indicated therein that Israeli was
no longer alive, though not mentioning the year of his death.



The Arab chroniclers of physicians indicate that Isaac Israeli served
as a doctor to Ubayd Allah al-Mahdi, the founder of the Fatimid
Dynasty of North Africa, who reigned from 910-934. In his
capacity as physician, Israeli wrote several medical treatises which
were widely regarded in the Islamic world, and highly valued in
Christian scholastic circles as well. These works include the *Book
of Fevers*, the *Book of Foodstuffs and Drugs*, and the
*Book of Urine*. Later Islamic historians relate accounts that
the first and third Fatimid rulers died from not following the sound
advice of Isaac Israeli, though the absence of these anecdotes in the
earlier chronicles, combined with their literary trope-like character,
render the tales suspect. Nonetheless, these narratives do indicate
the great respect accorded to Isaac Israeli.



Although the chronicler Ibn Abi Usaybi'a, as well as titles of
some of Israeli's work in manuscripts, assign Israeli the
patronymic term Abu Yacqub ("father of Jacob"),
the biographers state that he never married or fathered children, and
attribute to him the statement that his books will cause his name to
be remembered far better than children would. The assignment of
patronymics to persons who did not marry and beget offspring is not
altogether rare--thus we also see the patronymic "Abu
Ayub" applied to the childless poet and philosopher Solomon Ibn
Gabirol. As some of Israeli's treatises have survived over a
millennium and remain the occasional subject of scholarly research,
his prediction is correct.


## 2. Isaac Israeli's Philosophical Sources



Regrettably, in his surviving treatises, Israeli does not discuss his
philosophical studies. We do know that by Isaac Israeli's
lifetime, several Greek books of philosophy translated into Arabic as
well as original Arabic philosophical works were available, though
perhaps some of these treatises, mostly produced in Baghdad and its
environs, had not yet journeyed westward to North Africa. Much of
Aristotle's corpus had been translated in the previous century,
as had Porphyry's *Isagoge*, often studied as an
introduction to Aristotle's works. Further, an Arabic partial
paraphrase of Plotinus' *Enneads* circulated under the
pseudepigraphic title *The Theology of Aristotle* in two
recensions, the shorter of which is called the *Vulgate Theology of
Aristotle* (due to its larger number of manuscripts) while the
other recension is called the *Longer Theology of Aristotle*.
There are both significant parallels and significant variances between
Israeli's writings and the *Longer Theology* *of
Aristotle*. Thus, the influences of Aristotle and Plotinus on
Israeli's philosophy are strong, and he likely read translations
of their works as well as commentaries on them.



S.M. Stern argues for the existence of a lost pseudepigraphic Arabic
treatise which influenced the longer recension of *The Theology of
Aristotle* and Isaac Israeli, and was quoted without proper
attribution by both. Further, he argues that this same treatise is
identical to a philosophical excursus which was appended to the
literary tale *The Tale of the Prince and the Ascetic* (Hebrew:
*Sefer ben ha-melech veha-nazir*) when Abraham Ibn Hasday
translated the text from Arabic (*Bilawhar wa-Yudasaf*) into
Hebrew in the thirteenth century. Although one may be tempted to
conjecture that the Neoplatonist appendix is an original work by Ibn
Hasday which largely paraphrases Israeli--a hypothesis
strengthened by the fact that Ibn Hasday had translated
Israeli's *Book of the Elements*--Stern disproves
this possibility by demonstrating that Israeli's *Book of
Substances* is largely a commentary on the metaphysics of Ibn
Hasday's treatise, and Israeli's *Book on Spirit and
the Soul* is an attempt to reconcile Ibn Hasday's treatise
with scriptural proof texts. Hence, according to Altmann and Stern,
Israeli was strongly influenced by this treatise they call "Ibn
Hasday's Neoplatonist." Further, we know that Israeli did
not author this treatise, for when he quoted it, he cited "the
philosopher," thereby indicating that he thought he was quoting
Aristotle.



More recently, Fritz Zimmerman has argued that Stern's
hypothesis of an otherwise unattested "Neoplatonist" as
source for Israeli is superfluous. Israeli's source may have
been the *Longer Theology of Aristotle*, while Ibn
Hasday's source may simply have been Israeli, either
synthesizing the view's in Israeli's extant treatises, or
paraphrasing a lost treatise of Israeli's. In the absence of
further documentary evidence, neither Stern's nor
Zimmerman's theory can be definitively ruled out.



Isaac Israeli's passages on intellection, interpreted by Stern
as a misreading of al-Kindi, actually mirrors a passage in John of
Damascus' (c. 676-c. 749) *De Fide Orthodoxa*,
which was translated into Arabic in the tenth century (Wolfson, 1961:
279-280). While it is within the realm of possibility that
Israeli read this translation, it is also possible that both authors
are citing a previous source which is no longer extant.



A clear and strong influence of the Arab philosopher al-Kindi (d. 873)
is evident in the work of Isaac Israeli. Like the former, he wrote a
book of definitions, many of which are strongly similar to definitions
in al-Kindi's *Fi Hudud al-ashya' wa-rusumiha*.
Scholars Altmann and Stern illustrate the extensive similarities
between the two books in their commentary on Israeli's *Book
of Definitions* in their study *Isaac Israeli: A Neoplatonic
Philosopher of the Early Tenth Century*. Further, Israeli uses
much of al-Kindi's terminology for both astronomical and
terrestrial objects. Nonetheless, it would be wrong to call the book a
paraphrase of al-Kindi, as there are numerous divergences as well.



Though we see overlap with *The Theology of Aristotle* and
al-Kindi, we do not have any evidence that Israeli read the works of
his younger contemporary al-Farabi (ca. 870-ca. 950), nor do we
see the influence of his younger coreligionist philosopher Saadya Gaon
(882-942 C.E.).


## 3. Metaphysics


### 3.1 The Four Kinds of Inquiry



The four kinds of inquiry, introduced by Aristotle in his
*Posterior Analytics*, and subsequently modified by
Neoplatonist commentators, were such a universal and fundamental
component of the cultural *episteme*, that elaboration of the
four inquiries often formed part of the introduction to philosophical
and medical treatises. Aristotle lists the four questions thusly:



"(1) whether the connexion of an attribute with a thing is a
fact, (2) what is the reason of the connexion, (3) whether a thing
exists, (4) what is the nature of the thing." (*Posterior
Analytics* ii.1, G.R.G. Mure translation)



Following the practice of thinkers of his age, at the very beginning
of his *Book of Definitions* and also at the beginning of his
*Book on Fevers*, Isaac Israeli introduces the Aristotelian
distinction of the four kinds of inquiry, in a slightly modified
form:



"(1) The first is existence: when one inquires whether so-and-so
exists; (2) the second is quiddity: when one inquires what so-and-so
is; (3) the third is quality: when one inquires how so-and-so is; (4)
the fourth is 'quarity': when one inquires why so-and-so
is." (Altmann and Stern, *Isaac Israeli*, pp.
10-11)



Israeli's description mirrors the list of al-Jahiz (d. ca. 869)
in the *Book of Indications and Considerations* (Arabic:
*Kitab al-Dala'il wa'l-cItibar*) as well
as cAli ibn Sahl Rabban al-Tabari (fl. 9th
century), in his medical text *Firdaws al-Hikmah fi al-Tibb*.
His list varies slightly from that of al-Kindi, who in his treatise on
metaphysics *Al-Falsafah al-cula* defines the third
inquiry as *which*, rather than *how*.


### 3.2 The Four Causes



Just as medieval thinkers adopted Aristotle's four inquiries, so
too did they adopt his distinction of four types of causes (material,
formal, efficient, and final) elaborated in Aristotle's
*Metaphysics* v.2 and other places. Although Israeli adopts the
schema, he notes that within each of the four categories a cause can
be either spiritual or corporeal. While a "spiritual material
cause" might sound oxymoronic to our ears, in his *Book of
Definitions* Israeli provides an example:



> 
> A case of a spiritual material cause is that of the genera which are
> divided into their species and are the substratum for their forms
> which complete their speciality, as for instance 'living
> being', which is the genus of man and horse and other species,
> and is the substratum for their forms which constitute their essence.
> (Altmann and Stern, *Isaac Israeli*, p. 24)
> 



Just as spiritual material causes are the material substratum for
genera, spiritual formal causes are substantial forms of genera. These
genera "cause" those objects which partake of them to be
as they are. Israeli's example of a spiritual efficient cause is
paradoxical:



> 
> A case of the spiritual efficient cause is the power of the sphere
> which was appointed by the Creator, may He be exalted, in nature, and
> ordained in it over the effects which take place in the corporeal
> microcosm... (Altmann and Stern, *Isaac Israeli*, p. 25)
> 



The prevalent medieval conception of the sphere of the cosmos is that
it is not a vacuum, but rather, crystalline and composed of a fifth
element superior to the four elements of our terrestrial world. Hence,
it would appear that the efficient spiritual cause could also be an
efficient material cause. However, this difficulty is resolved if what
Israeli meant here was an intelligence or soul governing the sphere.
Although Israeli does not in any of his surviving writings and
fragments mention a soul of the spheres, his pupil Dunash Ibn Tamim
affirms it in his commentary on *Sefer Yetzirah*.


### 3.3 The Four Elements



Israeli adopts the Aristotelian doctrine of the four elements which
compose all material objects: earth, air, fire and water. These
elements are generated by the motion of the heavenly sphere, and they
inhere in a material substratum--though Israeli does not
elucidate its nature. Although Israeli does not explicitly state that
the elements are made up of form and matter, Altmann and Stern
(*Isaac Israeli*, p. 183) present a strong case for his
acceptance of this idea. In his *Mantua Text*, also known as
the *Chapter on the Elements*, he describes the generative
order of the elements. The motion of the sphere of the world generated
heat, and thus is fire brought into existence. As fire cooled, it
became air, which, moving away from fire, cooled and moistened into
water, and as water moved from air it cooled and dried and generated
earth (Altmann and Stern, *Isaac Israeli*, pp.
120-121).


### 3.4 Substance, Form and Matter



Similar to most other Neoplatonists, Israeli accepted the Aristotelian
definition of a substance as a something of which something is said or
predicated--and not something which is said of something else.
Within a substance, matter is the substratum for the form which
determines its being as substance. Further matter can be either
particular or general and universal, and if particular "it is
the substratum for a special form which constitutes the essence of a
particular species..." (*Isaac Israeli*, p. 86)


### 3.5 Theology



Although explication of the nature of God is absent in the surviving
fragments of Israeli's philosophical corpus, it is apparent that
Israeli, like the Muslim philosopher al-Kindi before him, combined the
Neoplatonist notion of God as the source of emanation of all things,
with the idea common to the monotheistic religions, of a willful
Creator who created the world in time. In blending these two
conceptions, these philosophers rejected the Aristotelian conception
of the eternity of the world, as well as the idea of eternal emanation
of some of the Greek Neoplatonists. Israeli's use of the Arabic
term, *al-Bari*, "the Creator" reflects the
religious sensitivities of his age--and is not simply a
translation of Plotinus' "The One".



In Plotinus' *Enneads*, the founding text of Neoplatonist
philosophy, *The One* contains a will which is not separate
from itself (*Enneads*, vi 8.21), and precedes the emanation of
*Nous* (The Intellect/Intelligence) a secondary entity from
which all lower beings emanate. In Arabic paraphrases of Plotinus, the
*Will* or *Word* of God is a secondary hypostasis which
creates *Intellect* (cAql). This model is also seen
in later Jewish Neoplatonist philosophers Solomon Ibn Gabirol and
Judah Halevi. However, Isaac Israeli, like Plotinus, does not treat
the will of God as a separate hypostasis or secondary being.



One prominent feature in most variants of Neoplatonist thought is
Negative Theology, the idea that one cannot predicate anything of God.
The problems which this approach intended to avoid were two undesired
implications arising from predication of a quality of
God--namely, that if we attribute a particular quality to God,
this quality exists co-extensively with God, and must hence be
co-eternal; secondly, it introduces multiplicity to God. The
Neoplatonists, in the main, wished to conceive of God as a simple and
radical unity, preceding all multiplicity in the world, and as such,
must precede the existence of qualities. Hence the only two allowable
predications of God are God's Unity and God's Existence.
In none of the surviving materials do we find Israeli expressing
Negative Theology explicitly. Israeli's pupil Dunash Ibn Tamim
promotes negative theology in his commentary on the mystical work
*Sefer Yetzirah*, which lead scholars Altmann and Stern
(*Isaac Israeli*, pp. 157-8) to conclude that we can
safely assume that Israeli held this opinion as well.


### 3.6 The Sequence of Emanation



Whereas for Plotinus, the second being in the emanative chain is
*Nous* (Intellect), Israeli concurs with the model in
"Ibn Hasday's Neoplatonist", that First Matter and
First Form are the first and only "creations" of the
Creator--that is, produced by an act of Will--and precede
the Intellect. First Matter and First Form conjoin to form the First
Intellect. After God creates First Matter and First Form, God's
active role in creation ceases and all subsequent beings emanate in a
chain of hypostases from Intellect, downward to the three kinds of
soul, and culminating in the material and corporeal Sphere/Nature.
Further, Israeli adds a second Intellect which is a distinct
hypostasis from First Intellect. First Intellect contains the totality
of forms and knows itself intuitively with perfect unchanging
knowledge. Second Intellect exists within the domain of Soul, and
knows the actualization of particular things via temporal
knowledge.



Soul is the next realm in the emanative sequence, and Israeli here
replicates Aristotle's threefold division. This universal soul
is made up of the higher Rational Soul, the Animal Soul and the
Vegetative/Nutritive Soul and from these emanates the superlunary
sphere of heaven--the point where the material world emerges from
Soul. Whereas most other Neoplatonists use the term
"Nature" for the corporeal world, Israeli uses the term
"the sphere." The motions of the superlunary sphere of
heaven, made up of a fifth unchanging element, govern the combinations
and recombinations of the four elements in the material world below
the moon--hence they govern the processes of generation and
corruption. Israeli's student Dunash Ibn Tamim calls this fourth
soul the soul of the sphere.


### 3.7 Metaphors of Light and Shadow



In Neoplatonist philosophy the metaphor of light emitted from its
source illustrates the process of emanation. The light spreads out
from its source, but does not diminish its source. Similarly, the
generation of emanated entities and hypostases in no way diminishes
the source of each emanation. Israeli accounts for the increasing
corporeality and particularity and imperfection of each emanated
hypostasis by adding the idea of shadow or shade to emanation. Each
emanated hypostasis has a lighter region closer to the source of its
emanation, but it also contains regions of shade or shadow in areas
further from their source. It is in these shaded regions that the
emanation of the next sequential entity begins. Further, each emanated
hypostasis receives light from its source but also shadow, which grows
denser as the ontological distance from the source of emanation
increases.


### 3.8 On Generation and Passing Away



As is standard within the intellectual milieu dominated by
Aristotelian physics, Israeli opined that the generation and passing
away of terrestrial objects was the result of recombination of
elements and their attendant properties (heat, coldness, wetness and
dryness), a process which is governed by the movement of the cosmic
sphere. Later thinkers would, via astrology, attribute certain roles
in this process to the "intelligences" governing
individual celestial objects and their relative positions. The
heavens, which are not composed of the four elements and hence not
affected by their contrary qualities, are not subject to generation
and degeneration. (*Isaac Israeli* [*Book of
Definitions*], p. 48)


## 4. Psychology


### 4.1 Intellect and Intellection



In a few instances in his *Book of Definitions*, Israeli
diverges from models given by his forerunner al-Kindi. Although
Israeli posits a *first intellect* and a *second
intellect*, Israeli describes three hypostases of intellect.
*First intellect*, the entity which emerges from the
conjunction of first matter and first form, contains all subsequent
forms, which emanate from the f*irst intellect* and determine
the specificality of all substances and knows all things eternally.
The secondary hypostasis of intellect is actually in the rational
soul, and is potential intellect before it passes into the actual
intellect of the first intellect. The "second intellect"
(actually the third hypostasis of intellect) is a faculty of the
rational soul, which via sense perception and imagination (the
"internal senses") conveys information to the higher
hypostasis in the rational soul. The second intellect of the rational
soul unites with the objects of its intellection in a spiritual,
non-corporeal sense and similarly, upon conveyance of the intellection
to the higher intellect of the rational soul, the higher hypostasis of
intellect within the rational soul also spiritually unites with the
objects of its intellection. (Altmann and Stern, *Isaac
Israeli*, pp. 36-7) Since Israeli here diverges from
al-Kindi, Stern accuses Israeli of a clumsy misreading of the latter.
(*Isaac Israeli*, p. 39) However, since Israeli's
description of internal senses largely mirrors the description in John
of Damascus' *De Fide Orthodoxa*, (Book II, Chapter 20)
it is likely that Israeli derived his overall schema of intellection
from another source. While Stern rejected the connection between the
text of John of Damascus and Israeli (Isaac Israeli, p. 59), Harry
Wolfson rejoined that *De Fida Orthodoxa* was available in
Arabic translation in the tenth century (Wolfson, 1961, p. 279).
Further, it is possible that Israeli was drew his conception from
another lost source common to himself and John of Damascus, or from a
lost Arabic commentator on the latter.


### 4.2 Soul, Spirit and Body



Isaac Israeli did not believe in the ensoulment of souls in bodies.
The three souls, despite their role in the governance of the body, and
the role of bodily sense perception in conveying information to the
rational soul, remained outside the body. In his *Book on Spirit
and Soul*, Israeli utilizes scriptural proof texts to argue that
the rational soul is what entitles mankind to reward or punishment
after death. But he writes tersely and vaguely on the subject of
reward and punishment and does not explicitly clarify the relationship
between the generic rational soul and rational souls of individuals.
Presumably, we all have separate rational souls, otherwise the idea of
reward and punishment of rational souls makes no sense. He notes that
the perfect actions of man pass beyond the corporeal sphere while
those actions to satisfy bodily appetites do not. Further, he affirms
that the soul of the righteous will endure in the upper realm with the
intellect. Although he has sidestepped the traditional Rabbinic Jewish
conception of bodily resurrection of the righteous by stating that the
world to come is the upper non-physical world, he does not spell out
whether this dwelling entails reintegration of one's rational
soul with the intellect, or a separate yet proximate existence.



Israeli, like the physician Qusta Ibn Luqa (ca. 835-912), argued
that in addition to its connection with souls, a living being has a
vital spirit, which unlike souls, is contained within the body and
dies with the body, and he employs scripture (Psalms 78: 39) to argue
this point. Altmann and Stern show that Israeli's text very
closely parallels Ibn Luqa's, hence either derived it directly
from the former, or they both are quoting the same prior source.
(*Isaac Israeli*, p. 50)


### 4.3 The Perfection of the Rational Soul



In addition to an emanative/generative order, a prominent feature of
Neoplatonist philosophy is the idea that through withdrawal from
bodily desires, and perfection of the intellect, one's rational
soul can attain unity with the higher world. The early
Neoplatonists--those outside of the "revealed"
monotheistic traditions of Islam, Judaism and
Christianity--suggest that it is possible for the rational soul
to achieve unity with The One/God. However, the Neoplatonists who were
members of established monotheist religions do not think that
one's rational soul is capable of so high an ascent up the
emanative chain, and advocation of such belief might have lead to
prosecution for blasphemy or heresy. Nonetheless, Neoplatonists of
religious traditions did think that the rational soul's union
with the realm of intellect was possible. Neoplatonists from Proclus
onwards describe unification as a three-part process, which Altmann
and Stern characterize as Purification--Illumination--Union.
For Israeli, the Purification stage involves three activities: an
ascetic rejection of bodily desires and pleasures, and the dominance
of the two lower souls; a worship of God combined with ethical
behavior towards one's fellow men; and the study of philosophy
to develop one's rational soul. In the second stage, the soul is
illuminated by truth. In the third stage, one's rational soul
becomes spiritual and divine, though not achieving full unity with the
Creator.


### 4.4 Free Will and Negation of Akrasia



According to Israeli, a human being can act in a number of ways when
faced with a specific situation. The reason for this ability is the
capacity of discernment, and more specifically of cogitation and
consideration. Due to these capacities people are able to acquire
theoretical and practical knowledge and to differentiate between good
and evil. Because animals do not possess intellectual capacities, they
are limited to acting in a definite way in particular situations.
However, the ability of humans to act in different ways is a
consequence of humans' position between pure intellect and
beast. People use their cogitation and consideration to attain a
higher level of knowledge. However, as long as humans use those
capacities their knowledge will remain imperfect and they will
continue to hesitate and be uncertain. When they are united with
intellect they no longer are uncertain and act in the best possible
way in all situations without any tension in their soul. According to
Israeli, the certainty of truth cancels all kinds of bad
temptations.



One may interpret Israeli here as saying that if a man has an
imperfect knowledge that it is bad to eat unhealthy candies, his
knowledge and his temptation for these candies are in struggle in his
soul. His capacities of consideration and cogitation
(lpkr) have to decide between this
imperfect knowledge and the temptation. Once this person attains
perfect knowledge, he or she no longer wishes to eat the candies. S.
Sadik argues that Israeli's remarks constitute a Socratic
negation of akrasia (Sadik 2013).


## 5. Philosophical Works, Manuscripts and Translations



All of the following works, except the *Book on the Elements*,
have been translated by Alexander Altmann and S. M. Stern in their
monograph *Isaac Israeli: A Neoplatonic Philosopher of the Early
Tenth Century*. In the 1950s and 1960s these two scholars have
also published transcriptions of the fragments and manuscripts of
these works in a number of journals. In addition to publishing and
translating known works of Isaac Israeli, Altmann and Stern firmly
established the hypothesis suggested by Gershom Scholem that Isaac
Israeli authored a work previously erroneously attributed to
Aristotle: *The Chapter on the Elements* (Mantua Text).
Further, in their extensive analyses of Israeli's texts (in
which they often compare Israeli's text to parallel passages in
al-Kindi and other authors), they established the surprising antiquity
of the Neoplatonic treatise which Abraham Ibn Hasday (d. 1240)
appended to his Hebrew translation of *The Prince and the
Ascetic*. This work, which they dubbed "Ibn Hasday's
Neoplatonist" actually predated and influenced both Isaac
Israeli and the *Longer Recension of the Theology of
Aristotle,* and Stern's article on "Ibn Hasday's
Neoplatonist" is an important component of any thorough study of
the philosophy of Isaac Israeli.


### 5.1 The Book of Definitions



Originally written in Arabic, this work is extant in two Latin (Liber
*de Definicionibus/Definitionibus*) and two Hebrew translations
(*Sefer ha-Gvulim*), but only a fragment of the original Arabic
(*Kitab al-Hudud*) survived. That this book was widely read by
Christian scholastics is evidenced by Thomas Aquinas' and
Albertus Magnus' misattribution of Avicenna's definition
of truth to Isaac's *Book of Definitions* (see Altmann
& Stern, *Isaac Israeli*, p. 59). This book is a collection
of 57 definitions, the bulk of which are paraphrases and quotes (often
without attribution) of various passages of al-Kindi. In some
instances, he cites "the philosopher" who would be
understood to mean Aristotle, but he is actually paraphrasing
al-Kindi, who oftentimes purports to elucidate what Aristotle had
written on a particular subject. Occasionally, his definitions derive
from other possible sources such as Qusta ibn Luqa (a physician,
mathematician, scientist and translator, lived 835-912 C.E.),
Ammonius Hermiae of Alexandria (Fifth Century C.E.) and John
Philoponus (490-ca. 570 C.E.). A few ideas expressed in this
work are not attested in any other known sources. Yet, because of the
book's close adherence to al-Kindi, Stern hypothesizes that
these deviations are often either quotation of definitions of al-Kindi
which have been lost, or are misreadings of al-Kindi. One of the
colophons at the end noted that the work is a
"collection," perhaps indicating that the material was not
original, nor intended to be read as such. In another manuscript the
colophon asserts that Isaac Israeli had written it, yet this same
colophon contains spurious information--that Israeli was from
Spain and that he had fathered children whom he hoped would study it
(Altmann & Stern, *Isaac Israeli*, p. 78), hence its claim
that the treatise is an entirely original work of Israeli's must
not be regarded as authoritative.



Both Latin versions were published by J.T. Muckle, "Issac
Israeli, Liber de Definicionibus" in *Archives
d'histoire doctrinale et litteraire du moyen age*,
1937-8. The longer version was translated by Gerard of Cremona
(1114-1187), and appears in manuscripts (Paris B.N. 14,700;
Paris B.N. 6443; Vatican Lat. 2186) as well as a printed edition
*Omnia opera Ysaac*, from Lyons in 1515. M. Alonso speculated
that the shorter version (MS Munich Lat. 8001) is a translation by
Domingo Gundissalinus and predated the longer version (Alonso, 1947,
pp. 295, 325) (See "Traducciones del arcediano Domingo
Gundisalvo" in *Al-Andalus*, 1947, pp. 295, 325). Altmann
and Stern challenge this hypothesis, arguing that the shorter version
is an epitome of the longer version, improving the translation at
points (*Isaac Israeli*, p. 5).



Nissim ben Solomon translated one of the Hebrew versions, and it can
be found in its entirety in H. Hirschfeld, *Festschrift zum 80.
Geburtstag M. Steinschneiders*, pp. 131-42. J.L. Teicher was
of the opinion that the Hebrew version was translated from the Latin
version (See "The Latin-Hebrew school of translators in Spain in
the twelfth century," in *Homanaje a Millas-Vallicrosa,
v.ii*, pp. 416-22). Julius Guttman and Stern think that his
primary source was the Arabic version (Stern and Altmann, *Isaac
Israeli,* p. 6). The second Hebrew translation, whose translator
is unknown, was published by Altmann in *Journal of Semitic
Studies,* 1957, pp. 232-42.



The surviving Arabic fragment is written in Hebrew characters, but
there are indications that the original text was written in Arabic
script. The Arabic fragment can be found in the Cambridge
Taylor-Schechter collection, document TS. 8 Ka.62 and has
been published twice--by H. Hirschfeld in "The Arabic
portion of the Cairo Genizah at Cambridge," Jewish Quarterly
Review xv (1902), pp. 689-93 and by Altmann in *Journal of
Semitic Studies,* 1957, pp. 232-42. This work is accessible
in English translation with commentary in Altmann and Stern's
*Isaac Israeli,* 9-78.


### 5.2 The Book of Substances



*The Book of Substances* (Arabic: *Kitab al-Jawahir*) is
extant only in fragments of Judeo-Arabic (that is, Arabic written in
Hebrew letters) in the Firkovitch Collection in St. Petersburg and in
the British Museum. Stern established that both manuscripts were
separately transliterated from an original text in Arabic
characters--which is deducible from transcription errors arising
from Arabic rather than Hebrew orthographic similarities, and that the
transcription and transliteration errors in the two manuscripts do not
match (Stern, "The Fragments of 'The Book of
Substances'", pp.16-17). Stern pieced together the
fragments, adding some missing materials from a passage in "Ibn
Hasday's Neoplatonist" and published them in the
*Journal of Jewish Studies,* vii (1956), 13-29. The
extant fragments largely paraphrase and add commentary to passages
from the pseudo-Aristotelian "Ibn Hasday's
Neoplatonist." Due to the close textual proximities between the
two texts, Stern conjectured that in places where Israeli is quoting
"the philosopher" he is likely quoting a lost passage of
the Neoplatonist. These parallels allowed Stern to arrange the
discontinuous fragments into an order mirroring its source treatise.
Altmann and Stern subsequently published a translation of the
fragments in *Isaac Israeli*, pp. 81-105.


### 5.3 The Book on Spirit and Soul



J.L. Teicher argues that Isaac Israeli is not the author of this work
(Teicher, 1956 p. 424). However, since Israeli's pupil Dunash
Ibn Tamim quotes passages of it in his commentary on the mystical work
*Sefer Yetzirah*, Teicher's view is likely erroneous.



Two Hebrew translations (*Sefer ha-Ruah v'ha-Nefesh*) and
a fragment of the Arabic original remain of this work. Altmann and
Stern provide a critical English translation based on the Hebrew
manuscripts (Munich Steinschneider's Cat. no. 307, fols. 47ff;
Cambridge Addler 1858 fols. 113v ff.) and A. Borisov's
publication of the Arabic fragment in *Isaac Israeli*, pp.
108-117.



This treatise, unlike the *Book of Definitions* and *Book of
Substances* is a distinctly Jewish work of philosophy, as it
combines doctrines of soul drawn from Ibn Hasday's Neoplatonist
with Jewish scriptural proof texts, supporting a Neoplatonist
conception of soul as distinct from mortal spirit, combined with the
Rabbinic Jewish belief in reward and punishment of souls.


### 5.4 The Chapter on the Elements



A single Hebrew translation (*Shacar ha-Yesodot
le-Aristo*) is extant in manuscript Mantua 28c, folios
16r-18r. This unsigned work was initially regarded as an
anonymous commentary on Aristotle. Altmann, developing a hypothesis
first proposed by Gershom Scholem, argues that this text is the work
of Isaac Israeli. Also called the *Mantua Text*, it is
available in English translation by Altmann in two
publications--*Journal of Jewish Studies,* vii (1956) pp.
31-57 and in Altmann and Stern's *Isaac Israeli,*
pp. 119-32.


### 5.5 Book of the Elements



Like most of his other philosophical works, Israeli's Arabic
original (*Kitab al-Ustuqussat*) is lost, and we are left with
a Latin translation and two Hebrew versions. Gerard of Cremona's
Latin translation of this book was published in the work *Omnia
opera Ysaac,* Lyons: 1515. One Hebrew version (Leiden, Warner MS
No. 13) was rendered by Abraham ibn Hasday for David Qimhi. The other
translation (Munich MS No. 43) is more eloquent, and likely an
improvement on the earlier translation, leading Salomon Fried to
conjecture that the famous Medieval translator Moses ibn Tibbon
(flourished mid-13th century, Provence) prepared it (Fried,
1884, pp. 75-83).


## 6. Israeli's Influence on Later Thinkers



In 956, Dunash Ibn Tamim, a pupil of Isaac Israeli, wrote an extensive
commentary on the short recension of *Sefer Yetzirah*, a
mystical work of cosmogony which attributes great importance to the
letters of the Hebrew alphabet and their combinations in determining
the structure of the universe. In this work he cites Israeli so
extensively that in the nineteenth century, a few scholars
misidentified the commentary as Israeli's.



Isaac Israeli's medical treatises were studied for several
centuries both in the original Arabic and in Latin translation. In the
eleventh century, Constantine Africanus, a professor at the
prestigious Salerno school of medicine, translated some of
Israeli's works into Latin. Many medieval Arabic biographical
chronicles of physicians list him and his works.



Israeli's philosophical works exercised a considerable influence
on Christian and Jewish thinkers, and a lesser degree of influence
among Muslim intellectuals. In the twelfth century, following a major
phase of the Christian reconquest of Spain, a group of scholars in
Toledo transmitted many Arabic works of science and philosophy into
Latin. One of the translators who migrated to this cultural center,
Gerard of Cremona, rendered Israeli's *Book of
Definitions* and *Book on the Elements* into Latin.
Israeli's work was quoted and paraphrased by a number of
Christian thinkers including Gundissalinus, Albertus Magnus, Thomas
Aquinas, Vincent de Beauvais, Bonaventura, Roger Bacon and Nicholas of
Cusa (See Altmann and Stern, *Isaac Israeli*, pp.
xiii-xiv; Julius Guttmann*, Die Scholastik des 13.
Jahrhunderts in irhen Beziehungen zum Judentum und zur judische
Literatur*, pp. 55-60, 129-30,150 and 172; as well as
Guttmann, *Das Verhaltniss des Thomas von Aquino zum Judentum und
zur judischen Literatur*, pp. 55-60).



Isaac Israeli corresponded with Saadya ben Joseph al-Fayyumi
(882-942) prior to the latter's departure from Egypt.
Saadya later became the head (Gaon) of the Talmudic Academy of Sura
and one of the most influential figures in the medieval Judaism.
Saadya Gaon was known for his Jewish legal rulings, his arrangement of
the Jewish prayer book (Siddur), his translation of the Hebrew Bible
into Arabic, his liturgical poetry and his philosophical work *The
Book of Beliefs and Opinions* (Arabic*: Kitab al-'Amanat
wal-'Itikadat*, Hebrew: *Sefer emunot
ve-decot*). Altmann and Stern suggest that it is
possible that Saadya Gaon's concept of rational commandments was
influenced by Israeli's concept of "intellectual
precepts" from his *Book of Definitions*. (*Isaac
Israeli*, p. 217) However, it is also possible that Saadya
Gaon's conception may have been a product of the vibrant and
somewhat ecumenical intellectual culture of Baghdad, in which a group
of theologians known as the Muta'zilites reconciled logic and
science with Islamic theology, arguing for the rationality of God and
His actions.



The great Jewish poet and Neoplatonist Solomon Ibn Gabirol (known in
Latin as Avicebron and Avicebrol) likely read Isaac Israeli's
works as well as the widely-circulated encyclopedic *Epistles of
the Brethren of Purity* (Arabic: *Rasa'il Ikhwan
as-Safa'*). Solomon Ibn Gabirol was at times close to the
latter in his models of emanation. He was also highly
innovative--hence the influence of Isaac Israeli is difficult to
gauge. Nonetheless, Israeli's *Book on Spirit and Soul*
was likely the only philosophical text which combined Neoplatonist
cosmology and psychology with Biblical proof texts--a task which
Ibn Gabirol accomplished so masterfully in his liturgical poem
*Keter Malkhut*. It is probable that Ibn Gabirol's idea
of spiritual matter was influenced by Israeli.



Another of the Golden Age Hebrew poets of Spain, Moses Ibn Ezra (c.
1060-1139) quotes Isaac Israeli without attribution in his
treatise *The Book of the Garden, explaining the meaning of
Metaphor and Literal Expression* (Originally in Judeo-Arabic:
*Kitab al-Hadiqa fi Macna 'l-Majaz
wa'l-Haqiqa*). Stern explores this matter in his article
"Isaac Israeli and Moses ibn Ezra." The poet and
philosopher Joseph Ibn Tzaddiq of Cordoba (d. 1149) authored a work
*The Microcosm* (the Judeo-Arabic original is lost, but the
work survived in Hebrew translation as *Ha-colam
ha-Qatan*) containing many ideas indebted to Israeli. Parallels
between the two thinkers are illuminated in Altmann and Stern's
*Isaac Israeli* (pp. 30, 44, 73-74, 117)*.*



Isaac Israeli's philosophical influence on Muslim authors is
slight at best. The only known quotation of Israeli's philosophy
in a Muslim work occurs in *Ghayat al-Hakim*, a book on magic,
produced in eleventh-century Spain, translated into Latin and widely
circulated in the West under the title *Picatrix*. Although
there are passages which correspond directly to Israeli's
writings, the author does not cite him by name.



As Neoplatonist philosophy waned, in addition to the Galenic medical
tradition of which Israeli was a part, the appreciable influence of
Isaac Israeli diminished as well.