หน้าหลัก Alfarabi, Avicenna, and Averroes, on Intellect: Their Cosmologies, Theories of the Active Intellect,..

Alfarabi, Avicenna, and Averroes, on Intellect: Their Cosmologies, Theories of the Active Intellect, and Theories of Human Intellect

A study of problems, all revolving around the subject of intellect in the philosophies of Alfarabi, Avicenna, and Averroes, this book starts by reviewing discussions in Greek and early Arabic philosophy which served as the background for the three Arabic thinkers. Davidson examines the cosmologies and theories of human and active intellect in the three philosophers and covers such subjects as: the emanation of the supernal realm from the First Cause; the emanation of the lower world from the transcendent active intellect; stages of human intellect; illumination of the human intellect by the transcendent active intellect; conjunction of the human intellect with the transcendent active intellect; prophecy; and human immortality. Davidson shows that medieval Jewish philosophers and the Latin Scholastics had differing perceptions of Averroes because they happened to use works belonging to different periods of his philosophic career.
ปี: 1992
สำนักพิมพ์: Oxford University Press, USA
ภาษา: english
จำนวนหน้า: 374
ISBN 10: 0195074238
ISBN 13: 9780195074239
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Alfarabi, Avicenna, andAverroes,
on Intellect

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Alfarabi, Avicenna, and Averroes,
on Intellect
THEIR COSMOLOGIES,
THEORIES OF THE ACTIVE INTELLECT,
AND THEORIES OF HUMAN INTELLECT

Herbert A. Davidson

New York Oxford
OXFORD UNIVERSITY PRESS
1992

Oxford University Press
Oxford New York Toronto
Delhi Bombay Calcutta Madras Karachi
Kuala Lumpur Singapore Hong Kong Tokyo
Nairobi Dar es Salaam Cape Town
Melbourne Auckland
and associated companies in
Berlin Ibadan

Copyright © 1992 by Herbert A. Davidson
Published by Oxford University Press, Inc.
200 Madison Avenue, New York, NY 10016
Oxford is a registered trademark of Oxford University Press
All rights reserved. No part of this publication may be reproduced,
stored in a retrieval system, or transmitted, in any form or by any means,
electronic, mechanical, photocopying, recording or otherwise,
without the prior permission of the publisher.
Library of Congress Cataloging-in-Publication Data
Davidson, Herbert A. (Herbert Alan), 1932Alfarabi, Avicenna, and Averroes on intellect: their cosmologies,
theories of the active intellect, and theories of human intellect /
Herbert A. Davidson,
p. cm. Includes bibliographical references and index.
ISBN 0-19-507423-8
1. Philosophy, Islamic—Greek influences. 2. Intellect.
3. Farabl. 4. Avicenna, 980-1037. 5. Averroes, 1126-1198.
6. Philosophy of mind. 7, Cosmology, Islamic. I. Title.
B745.I54D38 1992
153.9—dc20 91-38856

135798642
Printed in the United States of America
on acid-free paper

FOR

Mark, Elizabeth, and Abigail

This page intentionally left blank

Acknowledgments

Chapters 2, 3, and 4, have grown out of an article published in Viator 3 (1972).
Chapters 6 and 7 rework articles that appeared in Viator 18 (1987) and Viator 17
(1986), respectively.
My wife Kinneret read the entire manuscript meticulously and did her best to nudge
me in the direction of clarity and logic. My colleagues Hossein Ziai and Michael
Fishbein gave me invaluable assistance, the former in the reading of Suhrawardi, and
the latter in matters of Arabic. Michael Cohen, formerly of the UCLA Humanities
Computing Facility guided me through the hurdles attendant upon the preparation of
camera-ready copy. I extend warmest thanks to each of them.
All the translations are my own.
Los Angeles
May 1992

H. A. D.

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Contents

1. Introduction, 3
2. Greek and Arabic Antecedents, 7
Stages of Human Intellect, 9
The Kind of Entity That the Active Intellect Is, 13
The Active Intellect as a Cause of Human Thought, 18
The Active Intellect as a Cause of Existence, 29
Conjunction with the Active Intellect; Immortality, 34

3. Alfarabi on Emanation, the Active Intellect,
and Human Intellect, 44
Al-Madina al-Fd4ila and al-Siyasa al-Madaniyya, 44
Alfarabi's Philosophy of Aristotle, 63
TheRisalafial-cAql, 65
65
Alfarabi's Commentary on the Nicomachean Ethics, 70
Concluding Note, 73

4. Avicenna on Emanation, the Active Intellect,
and Human Intellect, 74
The Emanation of the Universe; the Active Intellect
as a Cause of the Existence of the Sublunar World, 74
Stages of Human Intellect; the Active Intellect
as the Cause of Human Thought, 83
Imagination, Cogitation, Insight, 95
Conjunction and Immortality, 103
Prophecy, 116
Summary, 124

5. Reverberations of the Theories of Alfarabi
and Avicenna, 127
Avicenna's Islamic Successors, 127
Reverberations in Medieval Jewish Philosophy, 180

Contents

X

Reverberations in Scholastic Philosophy, 209
Summary, 218
6. Averroes on Emanation and on the Active Intellect
as a Cause of Existence, 220
General Considerations, 220
The Emanation of the Universe, 223
The Active Intellect as a Cause of Existence: Epitomes of the
Parva naturalia and the Metaphysics, 232
The Active Intellect as a Cause of Existence:
The Commentary on De generatione animalium, 242
The Active Intellect as a Cause of Existence:
The Long Commentary on the Metaphysics and Tahdfut al-Tahdfut
(Destructio destructionum), 245
Summary, 254
7. Averroes on the Material Intellect, 258
Introduction, 258
The Epitome of the De anima and the Epistle on the
Possibility of Conjunction, 265
A Minor Composition on Conjunction and the Middle Commentary
on the De anima, 274
Averroes' Long Commentary on the De anima and
his Commentary on Alexander's De intellectu, 282
Summary, 295
Averroes' Theories of Material Intellect as Reflected
in Subsequent Jewish and Christian Thought, 298
8. Averroes on the Active Intellect
as the Cause of Human Thought, 315
The Passage of the Human Intellect to Actuality, 315
The Possibility of Conjunction with the Active Intellect;
Immortality, 321
Prophecy, 340
Averroes' Shifting Picture of the Universe and of Man's
Place in It, 351
Index, 357

Alfarabi, Avicenna, andAverroes,
on Intellect

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1
INTRODUCTION
The most intensely studied sentences in the history of philosophy are probably
those in Aristotle's De anima that undertake to explain how the human intellect
passes from its original state, in which it does not think, to a subsequent state, in
which it does. Aristotle started from the presupposition that human thoughts reflect
the external world without distortion, the antithesis of what would be Immanuel
Kant's perspective. Reasoning that the presence of any inborn quality would color
thoughts received by the human intellect and hence prevent the intellect from
performing its assigned task, he found the human intellect to be a "part of the soul"
which has the ability to "become each thing" but in itself originally has "no nature"
whatsoever other than the ability to think.1 Then came the statements that were to
echo down through the centuries. Aristotle brought to bear a dichotomy pervading
his entire philosophy, positing that the various domains of the physical universe
disclose both a "matter" and a "cause" or "agent"
which leads the
matter from potentiality to actuality; and he inferred that the same distinction must
also be "present in the soul." At the side of the intellect that is what it is "by virtue
of becoming all things," by virtue of acquiring all thoughts, an intellect must
consequently exist that is what it is "by virtue of making all things," by virtue of
making all thoughts.2 The intellect that is what it is "by virtue of becoming all
things" came to be known as the potential
or material
intellect, and the intellect that is what it is "by virtue of making all things," as the
active intellect
sometimes also translated as active mind,
active intelligence, active reason, agent intellect, productive intellect).
Just what Aristotle meant by potential intellect and active intellect—terms not
even explicit in the De anima and at best implied—and just how he understood the
interaction between them remains moot to this day. Students of the history of
philosophy continue to debate Aristotle's intent, particularly the question whether
he considered the active intellect to be an aspect of the human soul or an entity
existing independently of man.3 W. D. Ross has characterized "the famous
1

Aristotle, De anima 3.4.429a, 10, 21-22; 429b, 6.
Ibid. 3.5.430a, 10-15.
3
A sample: E. Zeller, Die Philosophic der Griechen 2.2, 4th ed. (Leipzig 1921) 573-75
(transcendent); F. Nuyens, devolution de la psychologic d'Aristote (Louvain 1948) 303-4, 308,
311 (transcendent); W. Ross, Aristotle, 5th ed. (London 1949) 153 (transcendent); idem, edition of
Aristotle's De anima (Oxford 1961) 45-47 (immanent); J. Rist, "Notes on Aristotle De anima
2

3

4

Alfarabi, Avicenna, and Averroes, on Intellect

doctrine of the active reason" as "perhaps the most obscure and certainly the most
discussed of all Aristotle's doctrines."4 While today the nature of the human potential intellect and active intellect is merely a problem of exegesis, a conundrum
exercising historians of philosophy, for two millennia it was a good deal more.
Despite, and also undoubtedly because of, the enigmatic quality of his words, the
Greek commentators on Aristotle, medieval Islamic, Jewish, and Christian philosophers, and European philosophers as late as the sixteenth century pored over the
master's words, seeking in them the key for deciphering man's essence, man's
fate, and the structure of the universe.
Alfarabi (d. 950), Avicenna (980-1037), and Averroes (1126-1198) integrate
the active intellect and human potential intellect into larger cosmic schemes. In each
instance, the physical universe comprises transparent celestial spheres, in which the
stars and planets are embedded, and a stationary sublunar world, around which the
celestial spheres rotate. A first supreme being consisting in pure thought, and
hence an intellect, presides over the entire cosmos; and there follow other beings
consisting in pure thought, that is to say, other intellects—or, as they are
conventionally termed, intelligences—which have the function of maintaining the
celestial spheres in motion. The active intellect, the cause of actual human thought,
stands at the end of the chain of supernal intelligences. In Alfarabi, Avicenna, and
the early Averroes, the intelligences, including the active intellect, are brought into
existence through a series of eternal emanations initiated by the First Cause; and
Alfarabi and Avicenna understand that the chain of emanations extends to the
celestial spheres and brings them into existence as well. All three philosophers
locate the human potential intellect immediately after the active intellect in the
descending order of existence.
The active intellect plays a towering role in the philosophic systems of Alfarabi,
Avicenna, and Averroes. Like the generality of medieval Islamic and Jewish
thinkers—and in contradistinction to the majority of Scholastic philosophers—they
did not doubt that the active intellect is an incorporeal substance transcending the
human soul and occupying a definite spot in the incorporeal hierarchy. Each of
them understood that the active intellect leads the human intellect from the state in
which it has a potentiality for thinking to a state in which it actually thinks, and each
explained the manner by which the active intellect performs that task. Each, in at
least some of his writings, also saw in the active intellect the cause of the existence
of segments or all of the sublunar world. Each affirmed the possibility of the
human intellect's entering a eudaemonic state called conjunction with the active
intellect, assigned the active intellect a central role in human immortality, and built a
rationale for the phenomenon of prophecy around the active intellect. They each
thus espoused a cosmic scheme in which a hierarchy of beings consisting in pure
3.5," in Essays in Ancient Greek Philosophy, ed. J. Anton (Albany 1972) 506-7 (immanent).
See also R. Hicks' edition of Aristotle's De anima (Cambridge 1907) lxiv-lxix.
4
W. D. Ross, edition of Aristotle's Metaphysics (Oxford 1924) l.cxliii. Ross himself
changed his mind; see n. 3.

Introduction

5

intellect unfolds until the active intellect is reached, in which the active intellect
serves as the transcendent cause of a portion or all of the sublunar world, in which
the transcendent active intellect leads the human intellect to actuality, and in which
the relationship of the active intellect to the human intellect explains phenomena
with religious overtones. The active intellect reached its culmination in Avicenna,
who saw it as the direct cause of all, or virtually all, existence and all theoretical
thought in the sublunar world, as, in effect, the vicar of God on earth.
A direct line of development is easily traced from Alfarabi to Avicenna, and then
forward to Averroes, but when one looks back beyond Alfarabi, no immediate
predecessor appears. Nevertheless, tendencies that crystallize in Alfarabi and
Avicenna, as well as specific propositions advanced by the two, are discernible in
the Greek commentators on Aristotle, in Neoplatonic philosophy, and in Arabic
writings before Alfarabi. That does not necessarily imply that Alfarabi took
material at his disposal and himself molded it into a comprehensive doctrine, which
was to be further developed by his successors. The positions Alfarabi put forward
may be borrowings from lost philosophic sources and not his own innovations.
The following chapter reviews discussions of intellect in late Greek and early
Arabic philosophy not for their own sake but as background for Alfarabi,
Avicenna, and Averroes. Chapters 3 and 4 examine the cosmologies, the
conceptions of the active intellect, and the theories of human intellect, espoused by
Alfarabi and Avicenna, respectively. Chapter 5 studies the reverberations of the
theories of Alfarabi and Avicenna, and especially the latter, in subsequent Islamic,
Jewish, and Scholastic philosophy. Chapter 6 takes up Averroes' struggles with
two issues on which he changed his mind several times: the relation of the First
Cause to the rest of the incorporeal hierarchy, and the active intellect's role as a
cause of the existence of the sublunar world. Chapter 7 attempts to untangle
Averroes' changing stands on another issue. Defining precisely the kind of entity
that the human material or potential intellect is had not been a central theme in
Alfarabi and Avicenna. Alfarabi barely touched on the question, and Avicenna dealt
with it indirectly as part of the more general question of the nature of the human
soul. Averroes, by contrast, wrestled with and agonized over the nature of the
human potential intellect throughout his career, changing his mind repeatedly.
Chapter 7 traces the development of his thought on the issue and then pursues the
subject beyond Averroes into subsequent Jewish and Christian thought that fell
under his influence. Chapter 8 examines Averroes' treatment of the active
intellect's role in leading the human potential intellect to actuality and his treatment
of subjects related to the active intellect's leading the human intellect to actuality,
namely, conjunction with the active intellect, human immortality, and prophecy.
Problems connected with intellect made up a considerable portion of the overall
philosophic enterprise for the three philosophers discussed, and their handling of
those problems reveals something of what can be called their philosophic styles. A
word about the philosophic style of each may be in place here. Different works of
Alfarabi sometimes advance differing positions on a single issue. To account for

Alfarabi, Avicenna, and Averroes, on Intellect

6

the discrepancies, scholars have suggested that Alfarabi's writings disclose a
development or, alternatively, that some of them express exoteric views, and
others, esoteric views. One striking trait exhibited by Alfarabi is that he almost
always lays down his positions flatly, without argument. My conjecture is
therefore that he may simply have been dependent on whatever sources were
available to him when he wrote,5 and the differing positions he advanced on
different occasions may simply reflect the sources from which he was working at
any given time. As for Avicenna, he mentions that he had developed an "oriental
philosophy" which diverged from the neoplatonized Aristotelianism he usually
espoused. Yet nothing of such a distinctively Oriental philosophy has ever come to
light. A medieval list of Avicenna's compositions names his Ishdrdt as the "last"
and "best" of them,6 and the theses espoused in the Ishdrdt, though formulated in
allusive and high-flown language, harmonize completely with what Avicenna's
primary philosophic treatises maintain. I accordingly assume that Avicenna was
consistent throughout his philosophic career and merely played with alternate
formulations.7 Averroes, like Alfarabi, takes differing stands on certain issues at
different times, but in his case the reason is clear. Throughout his lifetime,
Averroes labored to attain the truth, which for him was tantamount to recovering
Aristotle's intent, and in the course of rethinking issues, he repeatedly changed his
mind. Although Averroes' overriding goal was to cut away accretions and return to
Aristotle, we shall find that he did not always succeed. On two issues, the relation
of the universe to the First Cause and the active intellect's role as a cause of
sublunar existence, he gradually does reapproach genuine Aristotelian positions,
while on another, the nature of the human potential intellect, he starts with what the
consensus of scholars today would deem to be the genuine position of Aristotle and
then, in successive works, moves steadily off in the opposite direction, until he
arrives at an egregious misreading.
A remark on terminology: Greek and Arabic do not have separate terms for
intellect and intelligence, but a convention originating in the Latin Middle Ages
distinguishes the two, applying the term intelligence to the incorporeal beings that
in the Aristotelian world govern the celestial spheres, and employing the term
intellect in other contexts. Since the convention has become part of the idiom of
the history of philosophy and is useful, I distinguish intellect from intelligence
even though only a single Greek or Arabic word underlies the two terms.
5

The name of a scholar with whom Alfarabi studied logic has been preserved. See M.
Meyerhof, "Von Alexandrien nach Bagdad," Sitzungsberichte der preussischen Akademie der
Wissenschaften, Philosophisch-historische Klasse 23 (Berlin 1930) 405-8; F. Rosenthal, The
Classical Heritage in Islam (Berkeley 1975) 50-51.
6
The Life oflbn Sina (Juzjani's biography of Avicenna) ed. and trans. W. Gohlman (Albany
1974) 96-97.
7
D. Gutas, Avicenna and the Aristotelian Tradition (Leiden 1988) 115-130, makes the case
against assuming an Oriental philosophy which differed substantially from Avicenna's preserved
philosophic system.

2

GREEK AND ARABIC ANTECEDENTS

Here I shall examine Greek and early Arabic speculation on the following topics:
(1) the stages through which the human intellect can pass; (2) the type of entity the
active intellect is; (3) the manner in which the active intellect produces human
thought; (4) the active intellect's role in bringing the sublunar world or segments of
it into existence; and (5) the rationale that the active intellect furnishes for certain
religious phenomena. My object will not be to reproduce the systems of the
philosophers discussed but to draw attention to statements and theories that shed
light on Alfarabi, Avicenna, and Averroes.
As is hardly surprising, Aristotle constitutes the starting point for understanding
Alfarabi, Avicenna, and Averroes; certain post-Aristotelian Greek texts and early
Arabic philosophic texts, nevertheless, also contributed to the setting in which they
worked. The pertinent post-Aristotelian texts are: Alexander of Aphrodisias' De
anima1; a work entitled De intellectu, which is likewise attributed to Alexander,2
although the attribution has been questioned because of discrepancies between the
De intellectu and Alexander's De anima3; Plotinus' Enneads4; Themistius'
Paraphrase of Aristotle's De anima;5 Themistius' Paraphrase of Aristotle's

1

Alexander, De anima, in Scripta minora 2.1, ed. I. Bruns (Berlin 1887) 1-100.
Alexander (?), De intellectu, in Scripta minora 2.1, 106-13. Arabic translation: Texte
arabe du
d'Alexandre d'Aphrodise, ed. J. Finnegan (Beirut 1956), with pagination of
the Greek given; and Commentaires sur Aristote perdus en grec, ed. A. Badawi (Beirut 1968)
31-42. Neither edition of the Arabic version is wholly adequate. I have translated from my own
ad hoc eclectic text, which I base on both editions and their apparatuses, with corrections here and
there from the Greek.
3
P. Moraux, Alexandre d'Aphrodise (Paris 1942) 132-42. Moraux later changed his mind
and decided that both the De anima and De intellectu are genuine works of Alexander; see P.
Moraux, "Le De anima dans la tradition grecque," Aristotle on Mind and the Senses, ed. G.
Lloyd and G. Owen (Cambridge 1975) 297,304.
4
Plotinus, Enneades, ed. P. Henry and H.-R. Schwyzer 2 (Paris 1959) contains a useful
English translation of the extant Arabic paraphrases of Plotinus, done by G. Lewis.
5
Themistius, Paraphrase of Aristotle's De anima, in Commentaria in Aristotelem graeca
5.3, ed. R. Heinze (Berlin 1899). Medieval Arabic translation, with the pagination of the Greek
indicated: An Arabic Translation of Themistius . . . on Aristoteles 'De anima', ed. M. Lyons
(Columbia, S.C. 1973).
2

7

8

Alfarabi, Avicenna, and Averroes, on Intellect

Metaphysics, Book 126; a Greek commentary on Aristotle's De anima attributed
to John Philoponus7; and a different Greek commentary on Book 3 of the De
anima, also attributed to Philoponus, which is no longer extant in the original but is
preserved in a Latin translation.8 Of these, only the two works carrying
Alexander's name—the medieval Arabic philosophers were little inclined to
question the names on books and harbored no doubts about Alexander's authorship
of either work—and Themistius' paraphrases of Aristotle's De anima and of
Metaphysics 12, are known to have been directly available to the medieval Arabs
in Arabic translation. In the case of the De intellectu and of Themistius'
Paraphrase of Aristotle's De anima, the medieval Arabic translations have survived
and been published. While no manuscripts of the Arabic translations of
Alexander's De anima and of Themistius' Paraphrase of Metaphysics 12 are
known, medieval Hebrew translations from the Arabic have been preserved.
Avicenna refers to the views of both Alexander and Themistius on the soul,9 and
Averroes does the same10; in addition, Averroes quotes a key passage at length
from Themistius' Paraphrase of Metaphysics 12.11 Plotinus and his Enneads

were not even known by name, but parts of the Enneads circulated in Arabic in
anonymous and pseudepigraphous paraphrases, the most notable of which is the
Theology of Aristotle. The Theology of Aristotle is cited by Alfarabi as a genuine
work of Aristotle's,12 and Avicenna wrote a commentary on it.13
The following Arabic compositions from the period preceding Alfarabi also have
some pertinence: a paraphrase of Aristotle's De anima attributed to Ishaq ibn
Hunain (d. 876); a fragment from a certain Bakr al-Mawsili (ca. 900); the writings
of Kindi (ninth century); a treatise on the soul, of unknown date, which is attributed
6
The Greek original and the Arabic translation from the Greek are not extant. Medieval Hebrew
translation from the Arabic: Themistii in Arislotelis Melaphysicorum librum A paraphrasis,
ed. S. Landauer, in Commentaria in Aristotelem graeca 5.5 (Berlin 1903).
7
Philoponus, Commentary on De anima, in Commentaria in Aristotelem graeca 15, ed. M.
Hayduck (Berlin 1897).
8
Le commentaire de Jean Philopon sur le troisieme livre du traite de I'ame d'Aristote, ed.
M. Corte (Liege 1934).
9
See Avicenna, "Notes" on Aristotle's De anima, in Aristu cinda al- cArab, ed. A. Badawi
(Cairo 1947) 98, 101, 114, 116; Mubahathat, in Aristu °inda al-cArab, 120; Al-Qawl fl
Ahwdl al-Nafs, in Majmuc Rasa'il (Hyderabad 1935) 15.
10
See below, pp. 268-69, 274-75, 278-80, 282-84, 287, 326.
11
Averroes, Tafsir ma bacda al-Tabica (Long Commentary on Metaphysics), ed. M.
Bouyges (Beirut 1938-1948) 1492-94.
12
Alfarabi, Al -Jamc baina al-Haklmain, ed. A. Nader (Beirut 1960) 105-6. Also printed in
Alfarabi's philosophische Abhandlungen, ed. F. Dicterici (Leiden 1890) 28; German translation:
Alfarabi'' s philosophische Abhandlungen aus dem Arabischen iibersetzt, trans. F. Dieterici
(Leiden 1892) 44-45. Although several scholars have tried to interpret away what Alfarabi says,
he unambiguously recognizes Aristotle's authorship of the Theology.
13
Avicenna's commentary is printed in Aristu °inda al- cArab (n. 9 above) 35-74; French
translation: "Notes d'Avicenne sur la Theologie d'Aristote,'" trans. G. Vajda, in Revue thomiste
51 (1951) 346-406.

Greek and Arabic Antecedents

9

to Porphyry and extant only in Arabic. Avicenna refers to the Porphyry—or
pseudo-Porphyry—treatise, criticizing it harshly.14
Of the works that have been mentioned here, the most important for Alfarabi,
Avicenna, and Averroes are Alexander's De anima, the De intellectu, Plotinus'
Enneads, and Themistius' Paraphrase of Aristotle's De anima. As already noted,
parts of Plotinus were available to medieval Arabic readers in a paraphrase, and the
other three texts were available in translation. Where the Arabic translation or
paraphrase of a Greek text diverges from the original, the Arabic version is
naturally more germane for our purpose, and I shall usually quote from it.

Stages of Human Intellect
Each natural domain, Aristotle reasoned, discloses a "matter" that is "potentially"
everything in the domain, as well as an "agent" that makes everything in the
domain; whence he inferred that the soul too must contain an "intellect" that is what
it is "by virtue of becoming all things," as well as an intellect that is what it is "by
virtue of making all things."15 Aristotle's wording suggested the qualifications
potential and material for the undeveloped intellectual faculty of the human soul
which can become everything, that is, which can think all thoughts, and Alexander
of Aphrodisias therefore could, in a single sentence, call the initial state of the
human intellect both "potential" and "material" intellect.16 Commentators and
philosophers were to ask what sort of thing the potential or material intellect is.
Alexander's reading of Aristotle led him to conclude that it is "only a disposition" in
the human organism,17 whereas Themistius paid heed to statements of Aristotle's
pointing in another direction. He learned from Aristotle that the "potential intellect"
does "not employ a bodily organ for its activity, is wholly unmixed with the body,
impassive, and separate [from matter]."18 Since anything with those characteristics
is perforce an incorporeal substance, Averroes will consistently report that
Themistius and others of a similar mind took the human potential intellect to be an
incorporeal substance or, in another formulation, a disposition inhering in an
incorporeal substance.19 A modern commentator understands Themistius in the

14
Avicenna K. al-Ishardt wal-Tanblhat, ed. J. Forget, as Le livre des theoremes et des
avertissements (Leiden 1892) 180; French translation: Livre des directives et remarques, trans.
A. Goichon (Beirut 1951), with pages of Forget's edition indicated; Avicenna, Shifa': De anima,
ed. F. Rahman (London 1959) 240.
l5
De anima 3.5.430a, 10-15.
16
Alexander, De anima (n. 1 above) 81.
17
Ibid. 84.
18
Themistius, Paraphrase of theDe anima (n. 5 above) 105.
19
Cf. below, pp. 269, 279, 287.

Alfarabi, Avicenna, and Averroes, on Intellect

10

same way.20 The nature of the human potential or material intellect is mentioned
only in passing by Alfarabi, it is dealt with indirectly by Avicenna, but it becomes
central in Averroes.
Besides noting the existence of human intellect that can become everything,
Aristotle remarked on the situation wherein the human intellect has already "become
everything"—in other words, already possesses a full repertoire of thoughts—yet is
not actually thinking them at the moment. The human intellect in that condition is,
Aristotle wrote, "potential in a certain sense," because it is not actually thinking. It
is not, however, potential in the same sense as "before learning," because it has
undergone a passage to actuality. It is now "able through itself to think," much like
the "man of science" who is able to exercise his knowledge at will but does not at
the moment happen to be doing so.21 Alexander's De anima and the Arabic
Aristotelians who follow Alexander's example applied the term "intellect in habitu"
bil-malaka) to the human intellect when it is in
possession of a repertoire of thoughts—though not necessarily a full repertoire—
without actually thinking them.22
A further distinction, which although not brought out in Aristotle is obvious,
was alluded to by Alexander. Alexander commented that intellect in habitu stands
"between" the pure potentiality of the person who has not begun to acquire
intelligible knowledge and the full actuality of the man of knowledge currently
engaged in thought.23 Intellect in habitu, the stage in which the human subject has
20

40.

21

O. Hamelin, La theorie de l'intellect d'apres Arislote el ses commentateurs (Paris 1953)

Aristotle, De anima 3.4.429b, 5-9. Aristotle also discusses this sense of potentiality in De
anima 2.5.417a, 22ff.
22
See Alexander, De anima 85-86; De intellectu (n. 2 above) 107; Rasa'il al-Kindi, ed. M.
Abu Rida (Cairo 1950) 1.358 (the notion without the term); Avicenna, below, p. 84. Ghazali,
Maqdsid al-Faldsifa (Cairo n.d.) 292; Averroes, Epitome of De anima, published as Talkhis
Kitab al-Nafs, ed. A. Ahwani (Cairo 1950) 87. Elsewhere, Averroes uses the term intellect in
habitu in the sense of the human intellect possessed of a repertoire of thoughts, but without the
condition that the man is not thinking the thoughts at the moment. See Averroes, Iggeret
Efsharut ha-Debequt (Arabic original lost), ed. and English trans. K. Bland, as Epistle on the
Possibility of Conjunction (New York 1982), Hebrew text 12-13 (the English translation, p. 27,
incorrectly renders intellect in habitu as "acquired intellect"); idem, Commentarium magnum in
Aristotelis de Anima libros, ed. F. Crawford (Cambridge, Mass. 1953) (henceforth cited as: Long
Commentary on the De anima) 496-97. Themistius, in his Paraphrase of Aristotle's De anima
95, also takes cognizance of the condition in which intellect has undergone a passage to actuality,
without its actually thinking at the moment, and he appears to call that state a habitus; on 98,
however, he appears to use the term intellect in habitu in the sense of human intellect when fully
actual, rather than when in an intermediate state of potentiality. Alexander and Themistius
somehow thought that the term
which in the preserved text of Aristotle, De anima 3.5.430a,
15, qualifies the active intellect, refers instead to a state or stage of the developing human potential
intellect. See G. Rodier's note to the Aristotelian passage in his edition of Aristotle's De anima
(Paris 1900).
23
Alexander, De anima 85-86.

Greek and Arabic Antecedents

11

the power to think at will but is not doing so, may in other words be distinguished
from actual intellect, the stage in which the human intellect is actually thinking.24
The stages of human intellect have now increased to three: potential or material
human intellect, human intellect in habitu, and actual human intellect.
Alfarabi and Avicenna recognized still another stage or state, which they called
acquired intellect.25 The term acquired intellect reflects nothing in Aristotle. It
does appear in the Greek text of Alexander of Aphrodisias' De anima, although it
is inconspicuous there, serving only as a synonym for intellect in habitu, that is to
say, human intellect in possession of the ability to think yet not actually thinking.26
The term becomes significant in the Arabic translations of Alexander's De anima
and of the De intellectu attributed to Alexander.
Both Alexander's De anima and the De intellectu use a different expression,
"intellect from without," a number of times, echoing a perplexing passage in
Aristotle's De generatione animalium, which refers to intellect that "alone enters
[the organism] from without."27 Both works, as will be seen, deemed it possible
for an incorporeal substance, and the active intellect in particular, to enter the human
intellect and become the object of human thought; and they called that guise of the
incorporeal substance "intellect from without." The sense of the expression is that
such an object of thought already was intellect when still outside, and before being
thought by, the human intellect, in contrast to intelligible thoughts abstracted from
material objects and rendered actually intelligible, and therefore actual intellect, only
upon entering the human intellect.
In the Arabic versions of Alexander's De anima and the De intellectu attributed
to Alexander the words intellect from without are not translated literally. They are
generally rendered as "acquired intellect," and sometimes as "intellect acquired from
without."28 The Arabic versions have an another peculiarity; they substitute the
term acting (facil) intellect for the more precise term active (faccdl) intellect.
Thus, instead of speaking of an active, acquired intellect, which would show
unambiguously that the active intellect is what is qualified as acquired, the Arabic
translations speak of an "acting, acquired intellect."29 Although the collocation
24

Kindi, Rasa'il 1.358, draws such a distinction, without the term in habitu. TheDe
intellectu 107, and Themistius, Paraphrase of the De anima 98, do not recognize the distinction
between actual intellect and intellect in habitu.
25
On the subject of the acquired intellect, see A. Badawi, "New Philosophical Texts Lost in
Greek," Islamic Philosophical Theology, ed. P. Morewedge (Albany 1979) 4-5; F. Rahman,
Avicenna's Psychology (Oxford 1952) 90-93; Finnegan (n. 2 above) 172-78; P. Merlan,
Monopsychism Mysticism Metaconsciousness (Hague 1969) 14-15; and the references they give
to earlier literature.
26
Alexander, De anima 82. See E. Zeller, Die Philosophie der Griechen 3.1, 5th ed.
(Leipzig 1923) 826, n. 2.
27
De generatione animalium 2.3.736b, 28.
28
Cf. Finnegan (n. 2 above) 172.
29
Ibid. 186, 187. De intellectu 109, describes intellect in habitu as "acting."

Alfarabi, Avicenna, and Averroes, on Intellect

12

acting acquired intellect is cloudy, the Arabic translations do say enough to make
clear what acquired intellect means. According to the Arabic, acquired intellect
"exists actually"30 and is "in itself intellect"31; it comes to man "from without"32; it
"aids the intellect in [man]" and "establishes the habitus [for thought] within the
material intellect"33; it is the factor whereby the potential intellect is "led from
potentiality to actuality"34; it is "generated in us from without"35 and "we think
it."36 The descriptions reveal that a transcendent incorporeal entity, and the active
intellect in particular, is at issue. The added qualifications "acquired," or "acquired
from without," further indicate that the intellect in question somehow belongs to
man.
In a word, the Arabic translator of Alexander saw that the expression "intellect
from without" denotes the active intellect—or other incorporeal forms—insofar as it
somehow enters the human intellect; and for unknown reasons he rendered the
expression as acquired intellect. The Arabic does not misrepresent the intent of
the original, although, by coining the new name, it does draw additional attention
to, and permits a misunderstanding of, the aspect of the active intellect—or of
another incorporeal form—that enters man.
Plotinus likewise used the term acquired intellect. He meant by it intellectual
knowledge that is acquired by the soul directly from the supernal, cosmic
Intellect.37
Alfarabi and, in some contexts, Avicenna will employ the term acquired
intellect to designate not an aspect of the active intellect, or of another incorporeal
intelligence, which enters the human intellect, the sense the term has in the Arabic
translations of Alexander, but rather an ultimate stage of the human intellect itself, a
stage wherein the human intellect enjoys a certain close relationship with the
transcendent active intellect. With the addition of the acquired intellect, we have a
cadre of four stages: material or potential human intellect, intellect in habitu, actual
human intellect, and acquired intellect. The cadre does not appear precisely as such
in either Alfarabi, Avicenna, or Averroes. Each of them, however, employs a
variation of it.

30
31

lbid.

Hebrew translation of the Arabic version of Alexander, De anima 90, in Paris, Bibliotheque
Nationale, Hebrew MS 894.
32
Finnegan 191.
33
Ibid.
34
Ibid. 191.
35
Ibid. 186,194; Hebrew translation of Alexander, De anima 91.
36
Hebrew translation of Alexander, De anima 90.
37
Al-Shaykh al-Yunanl, ed. F. Rosenthal, Orientalia 21 (1952) 480-81, paralleling Enneads
5.6.4.

Greek and Arabic Antecedents

13

The Kind of Entity That the Active Intellect Is
Aristotle's meager remarks on the intellect that is what it is by virtue of "making all
things"—subsequently to be known as the active intellect—include both a suggestion that it is, and a suggestion that it is not, a transcendent substance. For he
described it as "present in the soul" yet also as "separate [from matter]... and,
in its essence, actuality."38 If primary weight be attached to the latter description
and the active intellect is understood to exist in an unchanging state of actuality, it
would have to be an incorporeal substance independent of the human organism.
The statement about its being present in the soul would then mean either that an
aspect of the essentially transcendent active intellect enters the human soul or else
merely that a cause as well as a matter must be assumed in the case of soul.39
Should, by contrast, primary weight be attached to the statement locating the
intellect that makes everything "in" the human soul, and should the active intellect
exist nowhere but in individual human souls, the description of it as "actuality" in
its essence will have to be interpreted away.
Alfarabi, Avicenna, and Averroes, like virtually all Islamic and Jewish philosophers in the Aristotelian tradition, accepted the transcendent interpretation without
question. And they did more. They pinpointed the precise place in the incorporeal
hierarchy where the active intellect stands—the words place, stands, and similar
terms being used metaphorically here, of course, since incorporeal substances exist
outside of space and time. In the medieval Aristotelian universe, a series of
incorporeal intelligences parallels the series of celestial spheres, the transparent
spherical bodies that carry the planets and stars around the earth. In the version of
the Aristotelian scheme of the universe endorsed by Alfarabi, Avicenna, and
Averroes, the active intellect, the factor leading the potential human intellect to
actuality, is added as a final link to the chain of intelligences. It therein parallels the
sublunar world, which stands as the last and least cosmic body, at the end of the
series of celestial spheres. The symmetry, as we shall see, can be extended,
through the ascription to the active intellect of functions in respect to the sublunar
world which are analogous to the functions each intelligence performs in respect to
the corresponding celestial sphere.
No known thinker prior to Alfarabi identified the active intellect precisely as the
last link in the chain of incorporeal intelligences, but the active intellect was
commonly taken to be a transcendent, incorporeal substance. The earliest known
philosopher who explicitly40 construed the active intellect as a transcendent being
38

Aristotle, De anima 3.5.430a, 13, 17-18.
Alexander, De anima (n. 1 above) 88, In the course of rewording Aristotle's reason for
positing an active intellect, writes that a material factor and an agent must exist "in the case of
intellect." Below, p. 20.
40
Aristotle's De generations animalium 2.3.736b, 28, and the Eudemian Ethics 1248a, 2529, may be read as construing the active intellect as a transcendent being. Theophrastus also
39

14

Alfarabi, Avicenna, and Averroes, on Intellect

was Alexander. Alexander connected the active intellect implied in Aristotle's De
anima, Book 3, with the first, incorporeal, ever-thinking cause of the universe
established in Aristotle's Metaphysics, Book 12. He assumed that the two entities
are identical, that the active intellect, the cause of the human intellect's passage from
potentiality to actuality, is nothing other than the First Cause of the universe, the
deity.41 Plotinus too, in a sense, construed the active intellect as a transcendent
entity. In his cosmology, the First Cause of the universe, called the One, eternally
radiates, or emanates, from itself a cosmic Intellect—which in turn radiates a
cosmic Soul; and among the functions for which the cosmic Intellect is responsible
are those of Aristotle's active intellect.42 Themistius was a third philosopher who
placed a transcendent construction on the active intellect. He rejected the
identification of the active intellect as the First Cause of the universe, or, to be more
precise, the proposition that the active intellect is the First Cause of the universe and
nothing more. His reason was that Aristotle had located the active intellect "in"
man's soul.43 But Themistius also insisted on the transcendent character of the
active intellect, or of its primary aspect, because Aristotle had—in an analogy that
would be analyzed and reanalyzed through the centuries—compared the active
intellect to light.44 The analogy of light entailed for Themistius that although rays
from the active intellect disperse and enter individual men, they have their origin in
an external radiating source, in a single transcendent "active intellect" existing
outside and above man. In a curious bit of syncretism, Themistius added that the
transcendent active intellect, or transcendent aspect of the active intellect, from
which rays radiate and enter individual human souls, is the very entity Plato had in
mind when he compared the Idea of the Good, the "cause of science and truth,"45
to the sun, the source of light.46
Other instances of the active intellect's being taken as a transcendent substance
are recorded in the two commentaries on the De anima attributed to John
Philoponus. Each of the commentaries lists four theories regarding the active
intellect, and one item in each list is of especial interest because it approaches still
further what was to be the conception of the Arabic Aristotelians. The Greek
seems to have construed the active intellect as a transcendent being; see Themistius, Paraphrase of
the De anima (n. 5 above) 102.
41
Alexander, De anima 89; cf. the De intellectu (n. 2 above) 113.
42
Cf. A. Armstrong, The Architecture of the Intelligible Universe in the Philosophy of
Plotinus (Cambridge 1940) 41.
43
Aristotle, De anima 3.5.430a, 13.
44
Ibid. 15-17.
45
Plato, Republic 6.508.
46
Themistius, Paraphrase of the De anima 102-103. Plotinus, Enneads 5.1.8, had identified
Plato's idea of the Good with the One, that is to say, with the First Cause, which is beyond
Intellect. If Themistius accepts the same equation, his argument that the active intellect cannot be
the First Cause of the universe is to be understood as contending only that the active intellect
cannot be the First Cause and nothing more, inasmuch as an aspect of it enters the human
intellect.

Greek and Arabic Antecedents

15

commentary attributed to Philoponus reports that a philosopher named Marinus47
viewed the active intellect as "something daemonic
or angelic."48 A
parallel statement in the commentary extant in Latin reports that "some" thinkers
identify the active intellect not as God but "as a certain other intellect, inferior to
Him, positioned close to our [intellect], which radiates upon our souls and perfects
them."49 In both statements, and more explicitly in the second, the active intellect
is an incorporeal substance outside man which stands close to man in the hierarchy
of existence. Alexander, Plotinus, and Themistius, by contrast, located the active
intellect at or near the top of the hierarchy of being.
Little is added by preserved Arabic works prior to Alfarabi.
At least two Arabic works do not recognize the transcendent character of the
active intellect. A paraphrase of the De anima attributed to Ishaq ibn Hunain
speaks of the active intellect as the "actual intellect" and states its functions briefly,
without any suggestion that it exists outside the human soul.50 An obscure
contemporary of Alfarabi known as Bakr al-Mawsili argues against the proposition
that the human intellect obtains knowledge through the action of an incorporeal
being outside of man. He contends instead that the "principles" of thought, which
are judgments about "the universal things," must be innate to the human intellect.
To explain the manner whereby man becomes conscious of the innate principles,
Bakr al-Mawsili has recourse to a Platonic theory of reminiscence.51
Kindi offered two distinct and, very likely, incompatible theories of the cause of
actual human thought.
His brief treatise On Intellect understands the factor actualizing the human
intellect to be a transcendent thinking being, which the treatise calls first intellect
rather than active intellect and describes as the "cause" of "all intelligible thoughts
and secondary intellects."52 Connections with Alexander have been detected, or are
thought to have been detected, in the text,53 and therefore Kindi might conceivably
be reflecting Alexander's position that the active intellect is identical with the First
Cause of the universe.
47

Probably identical with a student of Proclus by that name.

48

Philoponus (n. 7 above) 535. For the likely context of Marinus' statement, see H.
Blumenthal, "Neoplatonic Elements in the De Anima Commentaries," Phronesis 21 (1976) 81.
49
Commentaire
(n. 8 above) 30.
50
Ahwani (n. 22 above) 168.
51
S. Pines, "La doctrine de 1'intellect selon Bakr al-Mawsili," Studi. .. in onore di. . . Levi
della Vida (Rome 1956) 2.358-361.
52
Rasa'il al-Kindi (n. 22 above) 1.357. Medieval Latin translations of Kindi's On Intellect:
A. Nagy, Die philosophischen Abhandlungen des Jocqvb ben Ishaq al-Kindi (Minister 1897) 1—
11 (significant variants from the preserved Arabic); English translation: R. McCarthy, "Al-Kindi's
Treatise on the Intellect," Islamic Studies 3 (1964) 125-28; French translation: J. Jolivet,
L'intellect selon Kindi (Leiden 1971) 1-6.
53
Cf.
E. Gilson, "Les sources greco-arabes de 1'Augustinisme avicennisant," Archives

d'histoire doctrinale et litteraire du moyen age 4 (1929) 23-27; Jolivet 31-41.

16

Alfarabi, Avicenna, and Averroes, on Intellect

On a more plausible reading, however, Kindi's On Intellect is using the term
first intellect for the Intellect that is the second hypostasis in the Neoplatonic
hierarchy. A number of considerations support that reading: One of the Arabic
paraphrases of Plotinus employs the term first intellect precisely in the sense of the
cosmic Intellect.54 The Arabic text On the Soul attributed to Porphyry employs the
term first intellect in a Neoplatonic context and presumably again in the sense of
the Neoplatonic cosmic Intellect.55 The Jewish philosopher Isaac Israeli (ca. 850950) repeats the main points in Kindi's account of intellect56 but incorporates them
into a Neoplatonic hierarchy of Creator-Intellect-Soul-Nature.57 He apparently,
therefore, took Kindi's first intellect to be the second of the Neoplatonic
hypostases. Ibn Gabirol, a later Jewish Arabic philosopher standing in the
Neoplatonic tradition, explicitly applies the term first intellect to the hypostasis
Intellect, which is subordinate to the First Cause—incidentally adding that
philosophers call the same being "active intellect."58 And popular Neoplatonic
literature, in general, uses the terms first intellect as well as active intellect for
the cosmic Intellect of the Neoplatonic hierarchy.59
There is finally an unpublished text that, in the judgment of the scholars who
called attention to it, is Kindi's work. The text defines "universal intellect" by the
same distinctive formula that Kindi's On Intellect employed to define "first
intellect"; it defines universal intellect, and the treatise On Intellect defines first
intellect, as "the specificality of things."60 Assuming that the newly discovered text
does belong to Kind! or at least reflects his thought, we have first intellect equated
with universal intellect and presumably equivalent to the Neoplatonic cosmic
Intellect.
Such is one way Kindi represents the source of actual human thought. He
identifies it as the transcendent first intellect, which appears to be the second
hypostasis in the Neoplatonic hierarchy, standing under the First Cause of the
universe. In a separate work, entitled On First Philosophy, Kindi takes another
54

See Theology of Aristotle, ed. F. Dieterici (Leipzig 1882) 142, paralleling Enneads 6.7.2.
W. Kutsch, "Bin arabisches Bruchstiick aus Porphyries (?)," Melanges de I'Universite St.
Joseph 31(1954)268.
56
A. Altraann and S. Stern, Isaac Israeli (Oxford 1958) 35-38.
57
Ibid. 46-47.
58
The Arabic original is lost. Medieval Latin translation from the Arabic: S. Ibn Gabirol,
Fons vitae, ed. C. Baeumker (Miinster 1892-1895) 5, §19, p. 294; excerpts from the Arabic in
medieval Hebrew translation: Liqqutim, ed. S. Munk (Paris 1857) 5, §25.
59
See Long Version of the Theology of Aristotle, cited by P. Duhem, Le systeme du monde 4
(Paris 1916) 398-401; Rasa'il Ikhwan al-Sqfa' (Beirut 1957) 3.386, chap. 41; Ibn al-Sid
(Batlayusi) K. al-Hada'iq, ed. and Spanish trans. M. Asm Palacios, in Al-Andalus 5 (1940),
Arabic text 77; Spanish translation 118; medieval Hebrew translation: Batlajusi, ha-cAgullot haRaPyoniyyot, ed. D. Kaufmann (Budapest 1880) 27; K. Macanl al-Nafs, ed. I. Goldziher (Berlin
1907) 54; F. Rosenthal, "On the Knowledge of Plato's Philosophy," Islamic Culture 14 (1940)
399.
60
Altmann and Stern (n. 56 above) 37-38.
55

Greek and Arabic Antecedents

17

tack. He reasons that since actual human thought comes about when the human
intellect unites with the "species and genera of things," that is, with "the universals
of things," those universals must be the factor actualizing the human intellect.61 No
indication is given of the ontological status of universals. Kindi's wording does
recall Bakr al-Mawsili's "universal things" that are innate to the human intellect.
But since he speaks of the human intellect's "becoming" actual by uniting with
universals, he would seem to exclude its being united with them from the outset. In
other words, he seems to exclude universals' being inborn. He might, of course,
mean that the universals whereby the human intellect is actualized are embodied in,
and supplied by, the transcendent first intellect; for, as was just seen, he describes
first intellect as the "specificality of things," which is almost tantamount to saying
that first intellect embodies the universals of things. The statement that the
"universals of things" actualize the human intellect could, therefore, mean that they
do so when communicated by first intellect to the human intellect. The
harmonization, like all harmonizations, is tempting, but since the passage
describing universals as the cause of actual human thought does not mention a
transcendent intellect, we should beware of introducing one. The universals in the
passage may simply be concepts abstracted from physical objects; Isaac Israeli,
who was dependent on Kindi, outlined a process whereby human concepts are
refined from sense perceptions through successive abstractions.62 Or perhaps the
universals Kindi speaks of are abstract concepts subsisting in a Platonic world of
ideal Forms. In the passage under consideration, Kindi may, then, very well be
dismissing the need for any transcendent agent to lead the potential intellect to
actuality. He was fully capable of advocating diverse and inconsistent theories at
different times.63
Al-Kindi, in sum, offered two theories of the source of actual human thought.
According to one, the human intellect is led to actual thought by the transcendent
first intellect, by which he probably intended the Neoplatonic cosmic Intellect.
According to the other, the human intellect is rendered actual by the "universals of
things" with no further clarification. In yet another passage that might, at first
glance, appear pertinent, Kindi describes the heavenly bodies as the "agent of
[human] reason."64 There, however, he probably meant that the heavens generate
the human rational soul with its potentiality for thought,65 not that the heavens lead
the human rational soul to actual thought.

61

Rasa'il al-Kindl (n. 22 above) 1.155. English translation: Al-Kindi's Metaphysics, trans.
A. Ivry (Albany 1974) 106.
62
Altmann and Stern 36-37.
63
Regarding Kindi's eclecticism, see F. Rosenthal, "Al-Kindl and Ptolemy," Sludi ... in
onore di . . . Levi della Vida (Rome 1956) 2.438, 446, 454-56.
64
Rasail al-Kindl 1.255.
65
See below, p. 33.

Alfarabi, Avicenna, and Averroes, on Intellect

18

The foregoing survey discloses that post-Aristotelian Greek philosophers who
construed the active intellect, the cause of actual human thought, as a transcendent
entity identified it with the First Cause of the universe (Alexander); with Plato's
Idea of the Good (Themistius); and with the cosmic Intellect that is the second
hypostasis in the Neoplatonic hierarchy (Plotinus). Or they took it to be a supernal
being located below the deity and close to man in the hierarchy of existence (views
recorded in both commentaries on the De anima attributed to John Philoponus).
Among Arabic philosophic writings prior to Alfarabi, some recognize a
transcendent cause of actual human thought, which they call first intellect (a work
of Kindi's, the text attributed to Porphyry, Isaac Israeli), and others reject or ignore
the notion of such a cause (Ishaq ibn Hunain, Bakr al-Mawsili). In Kindi alone,
one work recognizes a transcendent cause of human thought, while another
accounts for the actualization of the human intellect without mention of it. Despite
the range of precedents for a transcendent construction of the active intellect or of
the cause of actual human thought under another name, no known writer before
Alfarabi identifies the active intellect as the last link in the hierarchy of celestial
intelligences, which parallels the sublunar world as each incorporeal intelligence
parallels its celestial sphere. Alfarabi was the first known philosopher even to
assume an entity of the sort, let alone identify it with Aristotle's active intellect.
The Active Intellect as a Cause of Human Thought
The active intellect was originally posited to help explain actual thought in man.
Each natural domain, in Aristotle's words, discloses a material factor, and also a
"cause" or "agent" that stands to the other as "art" stands to "matter" and "produces
everything" in the given domain; and therefore the soul too must contain both an
"intellect" that is what it is "by virtue of becoming all things," by virtue of receiving
all thoughts, and an intellect that is what it is "by virtue of making all things."66
In representing the active intellect as an instance of the cause or agent that
produces everything in a given domain, Aristotle's intent would surely appear to be
this: In each domain, a cause or agent operates on the material factor and leads it
from its state of potentiality to a state of actuality. Similarly, the intellect that is
what it is by virtue of making all things is such inasmuch as it performs an
operation on the intellect that is potential and resembles matter; and the operation
performed by the intellect that makes everything on the potential intellect brings
about a new condition in which the latter has become actual and possesses actual
thoughts. A fundamental proposition of Peripatetic philosophy would come into
play here, namely, as Aristotle explained elsewhere: Whenever "what exists
actually is generated from what exists potentially," the transition from potentiality to
actuality is effected "by means of what [already] actually is [in possession of the
66

Aristotle, De anima 3.5.430a, 10-15.

Greek and Arabic Antecedents

19

characteristic in question]."67 Obvious as that reading of Aristotle might be, a
reading according to which the active intellect performs an action on the potential
intellect rendering the latter actual, Alexander of Aphrodisias may not have accepted
it, and it has been challenged in modern Aristotelian scholarship.68 The medieval
Arabic Aristotelians, for their part, were certain that when Aristotle compared the
active intellect to the cause or agent in any given domain, he meant that the active
intellect performs a certain operation on the potential intellect and thereby brings it
to actuality.69
There remained the task of understanding how the active intellect—which the
Arabic Aristotelians took to be a transcendent substance—produces actual thought
in the human potential or material intellect.
Aristotle was not of great help. He did offer several observations about actual
human thought: The human intellect "thinks the forms in the images [found within
the human imaginative faculty]"70; "intellect is [related] to what is intelligible as
sensation is to what is sense perceptible"71; the intellect hence "is receptive of the
form" it thinks72; "actual knowledge is identical with its object"73—in other words,
an intellect becomes identical with whatever thought it thinks; although the human
intellect receives a form and becomes identical therewith, the intellect is not
"affected," or "altered" in the process, and is, moreover, free of affection and
alteration to a greater degree than sensation, which likewise, according to Aristotle,
is "not affected and altered."74 The statements tell us that the human intellect takes
forms from images in the imaginative faculty, thinks those forms, and becomes
identical with them, without being altered in the process.
But as for the role played by the active intellect, Aristotle offered only two
undeveloped analogies. First is the analogy already quoted which compares the
active intellect to the "art" that acts on matter. Then a few lines later, Aristotle
compared the active intellect to "light; for in a certain fashion, light makes potential
colors actual.. . ,"75 The analogy with light might well suggest that the active
intellect leads the human intellect to actuality by, in some sense, illuminating what is
67

Aristotle, Metaphysics 9.8.1049b, 24-25. Cf. Proclus, Elements of Theology, ed. E.
Dodds, 2d ed. (Oxford 1963), Proposition 77; that proposition cannot be identified in the material
known to have been translated from Proclus' Elements into Arabic.
68
See below, n. 80; W. D. Ross' introduction to his edition of the De anima (Oxford 1961)
43, 46-47.
69
One translation of the De anima into Arabic in fact paraphrases Aristotle and has him
establish not an intellect that is what it is by virtue of "making all things" but, instead, an
intellect "that is an intellect by virtue of making the other [potential or material intellect] think all
things"; see Averroes, Long Commentary on the De anima (n. 22 above) 437.
70
Aristotle, De anima 3.7.431b, 2; cf. De memoria 1, 449b, 31-450a, 1.
71
Ibid. 3.4.429a, 17-18.
72
Ibid. 15-16.
73
Ibid. 3.5.430a, 20.
74
Ibid. 3.4.429a, 15, 29-31; 3.7.43 la, 5.
75
Ibid. 3.5.430a, 15-17.

Alfarabi, Avicenna, and Averroes, on Intellect

20

intelligible in the world—or, more precisely, what is intelligible in images presented
by the imaginative faculty to the human intellect; and the potential intellect becomes
actual by, in some sense, viewing the illumined intelligible thoughts. Such a
reading of the analogy can find support in Plato's notion, surely known to
Aristotle, that man can "look at" the ideal Forms.76 Aristotle's De anima does not,
however, trouble to clarify what it has in mind. Having submitted the statements
about actual human thought and the bald comparisons to art and light, the De
anima turns away to other matters and leaves the commentators to their own
devices.
Alfarabi, Avicenna, and Averroes have two explanations of the manner by which
the active intellect effects actual human thought. In one, the active intellect casts a
kind of light on images in the human imaginative faculty and on the potential
intellect itself, thereby enabling the intellect to discern what is intelligible in the
images. In the other, the active intellect functions as a cosmic transmitter,
continually broadcasting all possible intelligible thoughts, and properly attuned
human intellects receive intelligible thoughts directly from the active intellect.
Antecedents for both explanations can be found in the late Greek and early Arabic
sources.
To begin, Alexander of Aphrodisias' De anima should be mentioned.
Alexander there rewords the Aristotelian grounds for positing an active intellect as
follows: "In all things generated ... by nature77. . . there is a matter,. . .
which is potentially everything in the given domain," as well as "an agent"
that effects "the generation, in the matter, of the things the matter is
receptive of." The distinction between matter and agent must also occur "in the case
of intellect." Hence, since "a material intellect
exists," there
"must likewise exist an active intellect
which is the cause of the
habitus of the material intellect,"78 that "habitus" being "a form . . . and
perfection" of the material intellect.79 Alexander would seem to be saying that the
active intellect acts upon the material intellect and produces a habitus for thought in
it. The ensuing account of the active intellect's role in human thought pursues a
different line, which is of considerable interest in itself but not pertinent to the
Arabic philosophers whom we are studying.80
76

Plato, Republic 484C; Euthryphro 6E.
77

More precisely: "In all things generated ... by nature which do have a matter... there
is a matter...." Alexander is leaving open the possibility of things that are generated, yet
contain no matter.
78
Alexander, De anima (n. 1 above) 88.
79
Ibid. 85.
80
Alexander lays down the proposition that whatever has a given characteristic to the "highest
degree and preeminently,... is the cause of other things' being such." (The converse was

affirmed in Aristotle, Metaphysics 2.1.993b, 24-26: If something is the cause of other things'
having a certain characteristic, it itself possesses the characteristic to a higher degree.) Alexander
explains the proposition in a Platonic spirit: When something has a quality "preeminently" and

Greek and Arabic Antecedents

21

The De intellectu, which was read by the Arabic philosophers as a companion
piece to Alexander's De anima, makes a number of points about the active
intellect's role in producing human thought; and they, although disjointed and
probably not even consistent with each other, are highly pertinent.
The first point is put thus in the Arabic translation of the De intellectu: What
"produces intellectual thinking and leads the material intellect to actuality" is the
"active" intellect, a being that is "intellect in actuality" and as a consequence
"actually . . . and by its own nature . .. intelligible."81 The active intellect is,
"as Aristotle says,.. . analogous to light,"82 for "light is the cause making colors
that are potentially visible, actually so." If the analogy with light were intended at
face value, the active intellect must somehow illumine potential objects of intellect
and thereby transform them into actual objects of intellect. But in the present
passage, the De intellectu ignores the implications of the analogy83 and draws
only the unfocused inference that the active intellect leads the material intellect to
actuality: As light makes potential colors visible to the eye, "so too this [active]
intellect renders the material intellect, which is in potentiality, an actual intellect."
The active intellect renders the material intellect actual "by fixing a habitus for
intellecting thought [Greek: the intellecting habitus] in" the material intellect.84 A
similar formulation was just met in Alexander's De anima.
In what may or may not be an amplification of the way the active intellect brings
the potential intellect to actuality, the De intellectu goes on to allude to Aristotle's
remark, in De generatione animalium, that "intellect alone enters [the organism]
from without."85 The De intellectu explains, in the language of the medieval
Arabic version: When the active intellect "becomes cause of the material intellect's
something else has it "secondarily," "what [has the quality] secondarily receives existence from
what [has it] preeminently." He gives two examples: "light," which is "to the highest degree
visible" and is the cause of "other things' being visible"; and that which is to "the highest degree
and primarily good" and is the cause of "other things'" being good. Applying the rule to intellect,
Alexander finds that the transcendent active intellect, which is "preeminently and by its own nature
intelligible," can "with reason" be considered the "cause of other things' intelligible thought"
(Alexander, De anima 88-89). In a word, the active intellect is known to be the cause of human
thought not because it is found to do anything, but inasmuch as it is the being with the highest
degree of intelligibility.
Alexander adds a further bland consideration: "If the active intellect is "the first cause" of the
universe—as Alexander in fact took it to be—it "would," by virtue of being the cause of the
universe, also "be" the ultimate "cause of the existence of all intelligible thoughts." The active
intellect may, in other words, be deemed the cause of human thought in the most broad sense of
being the cause of everything in the universe (Alexander, De anima 89). Neither here nor
elsewhere in the treatise does Alexander describe a definite action or operation performed by the
active intellect on the human material intellect.
81
81De
intellectu (n. 2 above) 107-08.
82

Ibid. 107.

83

See Moraux, Alexandre d'Aphrodise (n. 3 above) 126-27.

84
De
intellectu 107.
85
Aristotle, De generatione animalium 2.3.736b, 28.

Alfarabi, Avicenna, and Averroes, on Intellect

22

abstracting, receiving, and conceiving every material form [as an intelligible
thought]," it "is called the acting acquired intellect [Greek: the active intellect...
from without]"; for it is "not any part and power of our soul, but rather appears in
us from without."86 If the statements quoted so far may be correlated, the De
intellectu maintains that the transcendent active intellect enters man from without, it
fixes a habitus for thought in the human intellect, it thereby leads the potential
intellect to actuality, and the human intellect begins to think.
Still a further amplification, or perhaps an alternative position, follows. Aristotle
had drawn a parallel between intellect and sense perception,87 and the De intellectu
plays on the parallel to expound what it calls "Aristotle's"88 reasons for
"introducing an acquired intellect [Greek: the intellect from without]." The
exposition begins with the assertion that whenever anything "comes into existence,"
three factors must be present. These are "something undergoing affection,
something active
and a third thing,... namely, that which is
generated ... from them." In sense perception, the three factors are "the sense
faculty,. . . the sense perceptible, and something generated, namely, the
perception
" And by analogy, thought too must contain a similar set of three
factors. The argument focuses on the second of the factors found in all processes
whereby things come into existence, hence in sense perception, and hence in
thought as well.
The second factor in all processes is "something active." In sense perception,
where the De intellectu calls the second factor "the sense perceptible," the text
accordingly explains that the factor in question is "something active," an agent
enabling the sense faculty to pass to actuality. Since thought requires the same set
of factors, it too must have a factor with the character of the second one in sense
perception, with the character of the factor rendering the sense faculty actual. And
such a factor in thought can be nothing other than "an actual active intellect."
Consequently, "just as there exist things that are actually sense perceptible and that
render sensation actual, so too there must exist things that, being themselves
actually intelligible, render the ... intellect actual."89 There must exist "an actual
active intellect that renders the hitherto potential intellect capable of thinking,"
"brings the material, potential intellect to actuality," and renders "all existent things
86
De
inlellectu 108.
87

Above, p. 19.
In the sequel, not quoted here, the De intellectu ascribes plainly Stoic theories to this
"Aristotle"; see below, p. 30. Zeller, followed by Bruns, the editor of the De intellectu, therefore
ingeniously conjectured that "Aristotle" is a copyist's error for "Aristokles," the name of
Alexander's supposed teacher. See Zeller (n. 26 above) 815. P. Moraux, Der Aristotelismus bei
den Griechen 2 (Berlin 1984) 83 and n. 6, has responded that Alexander had a teacher named
Aristotle and that the reference is to him. See also F. Trabucco, "II problema del de Philosophia di
Aristocle di Messene e la sua doctrina," Acme 11 (1958) 117, 119.
89
The Arabic manuscripts are garbled here. My translation is partly conjectural but it is
compatible with the Greek original.
88

Greek and Arabic Antecedents

23

intelligible." This factor in thought, which parallels what is actually sense
perceptible, and which brings the human intellect to actuality, is an "intellect...
entering from without," according to the original Greek. It is "acquired from
without," according to the medieval Arabic translation.90
The De intellectu fails to identify what it is that is actually sense perceptible and
that makes the sense faculty actual. When Averroes later read the De intellectu,
he understood that in the case of vision, the actually sense perceptible is light,91 and
the pages in the De intellectu coming after the statements just quoted tend to
corroborate Averroes' interpretation.
The De intellectu now argues the new, unexpected proposition that the human
material intellect is not, after all, wholly "passive" but is "active" as well, and
further that it develops spontaneously, as the "ambulatory faculty" in man
spontaneously passes to actuality with time.92 To illustrate how the human intellect
can be both active and passive, the De intellectu expands the repertoire of
analogies by comparing the human intellect to an additional phenomenon, fire. Fire
has two sides. It has an active side, which "destroys ... matter," but at the same
time it also "feeds on" matter, and "insofar as it feeds on matter, it passively
undergoes affection." Similarly, the "acting \fdcil] intellect in us"—which here
means the human material intellect, described in the lines immediately preceding as
active—both "separates off forms through its active side and "takes hold" of them
through its passive side. Lest anyone suppose that recognizing an active side of the
human intellect leaves the transcendent active intellect otiose, the De intellectu
insists: Although the human potential intellect develops spontaneously, the active
intellect "acquired from without [nonetheless] . .. assists the human intellect."
The need for an active intellect is justified through the familiar analogy of light,
already mentioned in an earlier passage of the De intellectu, and at this point the
De intellectu extracts a little more from the analogy than it previously did.
"Light.. . produces. .. actual sight" and, concomitantly with being "seen
itself," renders "color" visible. Human thought similarly requires an active intellect
that enters man and becomes "an object of thought" (according to the Greek but
blurred in the Arabic translation), thereby "perfecting" the already active material
intellect and "fixing the habitus [for thought] in it."93 In perfecting the human
intellect, the active intellect becomes itself an actual object of thought, just as light
becomes an actual object of sight in the course of activating the faculty of vision.
In sum, the De intellectu first states generally that the active intellect renders the
material intellect actual by entering man from without and fixing a habitus for
thought in the material intellect; Alexander, or whoever wrote the work, supports
90

De intellectu 110.
Below, p. 325.
92
Alexander's De anima 82, instead contrasts the ambulatory faculty, which becomes
actualized naturally, with the intellectual faculty, which does not.
93
Ibid. 111.
91

Alfarabi, Avicenna, and Averroes, on Intellect

24

the statement through Aristotle's comparison of the active intellect to light yet
ignores the analogy's implications. The De intellectu then develops another
Aristotelian notion and compares the process of thought to the process of sensation.
The parallel with sensation leads to the conclusion that human material intellect is
activated by the active intellect in the way that the sense faculty is activated by what
is actually sense perceptible. In a final clarification of the nature of actual human
thought, the De intellectu submits that the material intellect is itself active, like fire,
and develops spontaneously, like the ambulatory faculty. But even when
recognizing an active side of the human intellect, the De intellectu still insists on
the need for an external active intellect. The external active intellect enters the
material intellect from without and becomes its actual object of thought, as light,
besides illumining visible objects, serves as the actual object of vision.
Of interest for us in Plotinus is not his full doctrine of intellect but selected
remarks.
Plotinus' cosmic Intellect has a certain resemblance to the Aristotelian active
intellect, the cause of actual human thought, and the resemblance increases when
the active intellect is taken to be a transcendent substance. It is hardly surprising,
therefore, that Plotinus employed what was to become the standard argument for
the existence of the active intellect as an argument for the existence of his own
cosmic Intellect. In the wording of the Arabic paraphrase of the Enneads, an
intellect must exist which brings about actual thought in soul, because "potentiality
passes to actuality only through a cause that is in actuality similar to [what] the
[former is in] potentiality."94 In the original Greek, the argument is designed to
prove that above the hypostasis Soul there stands the hypostasis Intellect. The
Arabic paraphrase leaves uncertain, however, whether cosmic Soul or individual
human souls are at issue. The anonymous Arabic paraphrase offering the argument
might thus be treated as a text belonging to the Peripatetic mainstream, and the
argument read as establishing the existence of an already actual intellect that brings
the human rational soul to the state of actual thought.
Part or all of human intellectual knowledge is, for Plotinus, communicated to the
human rational soul directly by the cosmic Intellect. Plotinus writes that whenever
"a soul is able to receive," Intellect "gives" it clear principles, and then "it [the soul]
combines" those principles "until it reaches perfect intellect."95 In other passages
the scope of the knowledge communicated by Intellect is broadened beyond "clear
principles." In the wording of one of the Arabic paraphrases of Plotinus: "The
intellectual sciences, which are the true sciences, come only from Intellect to the
rational soul."96 And the paraphrase known as the Theology of Aristotle brings
94

Risala ft al-cllm al-flahi, in Plotinus apud Arabes, ed. A. Badawi (Cairo 1955) 168,
paralleling Enneads 5.9.4. For the principle, see above, p. 18, and cf. Theology of Aristotle (n.
54 above) 38, paralleling Enneads 4.7.83.
95
Enneads
1.3.5.
96Risdlafi al-cllm al-flahl 169, paralleling Enneads 5.9.7.

Greek and Arabic Antecedents

25

the matter-form dichotomy to bear, maintaining: Soul has "the status of matter," it
"receives the form of Intellect, and "reason occurs in soul only thanks to
Intellect."97 The original Greek text of the last passage again had cosmic Soul, and
not the individual human soul, in view. But Avicenna's comment on the passage as
it appears in the Theology of Aristotle, shows that he took soul in the sense of the
human soul, and intellect in the sense of the "active intelligences."98 On such a
reading, the human rational soul is a kind of matter that is perfected and receives all
its intellectual knowledge through a form coming from an incorporeal intelligence.
Plotinus depicts the situation of the human soul vis a vis the cosmic Intellect
through a metaphor that will recur over and over again in Arabic literature. The
soul, he writes, contains a sort of mirror wherein images of thought and Intellect
are reflected when the soul orients itself properly toward the higher world.99
Two more passages deserve to be mentioned. The first, which did not pass into
the preserved Arabic paraphrases, says that man has intellectual thoughts
"in two ways." "In intellect," which seems to mean insofar as the human intellect
remains part of the cosmic Intellect, man has intelligible thoughts "all together"; "in
soul," that is to say, in his rational soul, which is an offshoot of the cosmic Soul,
or perhaps of the cosmic Intellect, he has them "unrolled and discrete, as it
were."100 The second passage says that "the soul contains an acquired intellect
c
aql muktasab] which illuminates it [that is, which illuminates the
soul] . .. and renders it intellectual."101
If we do some violence to Plotinus by reading him primarily in the Arabic
paraphrase and fitting the scattered quotations together in a synthesis, while
ignoring much more that is central to his system, we get the following: A
transcendent Intellect has to be assumed in order to account for the passage of the
human rational soul from potentiality to actuality. Intellectual knowledge is
transmitted directly by the transcendent Intellect to human rational souls that are
properly oriented and ready to receive Intellect's bounty. The human intellect is like
a mirror in which intelligible thoughts from above are reflected. Thought at a
higher level, at the level of Intellect, is all together, which can be taken to mean that
it is undifferentiated; at a subsequent level, it is unrolled, which can be taken to
mean that thought becomes differentiated as it descends into the human rational
soul. The relation of the human rational soul to the intelligible thought it receives
is—as Aristotle already suggested and Alexander wrote explicitly—a relation of
matter to form; and Plotinus adds that "clear principles" and the "intellectual
sciences" constituting the form of the rational soul come directly from the
transcendent Intellect. Because thought is acquired by the human intellect from
97Theology of Aristotle 105-6, paralleling Enneads 5.1.3.
98

Cf. Avicenna's commentary on the Theology of Aristotle (n. 13 above) 72.
"Enneads 1.4.10.
100
Enneads 1.1.8. Plotinus held that the human intellect does not descend from the cosmic
Intellect into the human body. See Blumenthal (n. 48 above) 73-74.
101
Al-Shaykh al-Yunani (n. 37 above) 480-81, paralleling Enneads 5.6.4.

26

Alfarabi, Avicenna, and Averroes, on Intellect

above, actual human thought is acquired intellect. When the foregoing statements,
which are made here and there by Plotinus, are thus combined, they prefigure
Avicenna's account of the manner whereby the active intellect acts on the human
intellect.
Turning to Themistius, we find him laying down the rule that "nothing is
perfected by itself and inferring at once the existence of "an actual, perfect
intellect," which leads the human intellect to actuality and perfection. Part of
Themistius' justification for assuming a single active intellect for the entire human
species is that all men grasp the same "common notions," "first definitions," and
"first axioms," without being taught.102 His intent could be either that the single
active intellect communicates the principles of thought directly to the human
intellect, or that it enables the human intellect to discern the principles of thought in
sense perceptions and extract them from there.
In a possible echo of Plotinus, Themistius describes thoughts as "all together" in
the active intellect, while in "the potential intellect they are differentiated."
Thoughts that the active intellect "gives undividedly," the human intellect "cannot
receive undividedly" but only in a differentiated mode.103 Nevertheless, despite
having described the active intellect as giving thoughts undividedly, Themistius
does not mean that it conveys thoughts—with the possible exception of the first
notions, axioms, and definitions, which were just mentioned—directly to the
human mind. So much is plain when he deploys Aristotle's analogy of light in
order to explain the interaction of active intellect and potential intellect.
The implication of the analogy receives more attention from Themistius than it
did from Alexander. Themistius writes: When "light becomes present in the
potential faculty of vision and in potential colors, it turns the former into actual
vision and the latter into actual colors." In an analogous manner, the active intellect
joins "the potential intellect," acts on it, and acts as well on man's "potential
intelligible thoughts"; potential intelligible thoughts, which parallel potential colors,
are sense perceptions, mediated by the imaginative faculty and stored in the human
memory. The active intellect turns the potential intellect into "actual intellect" and
renders potential thoughts "actually intelligible to" the human intellect.104 In other
words, the active intellect, functioning as a sort of light, activates both images in the
soul, which are potential thoughts, and the human potential intellect; and it thereby
enables the potential intellect to perceive actual thoughts and to become actual itself.
Besides exhibiting, after a fashion, how the active intellect renders the human
intellect actual, the analogy serves the further purpose of helping Themistius grasp
how the active intellect, although a transcendent being, can have been located by
102
Themistius, Paraphrase of the De anima (n. 5 above) 98, 103-4. There is a certain
similarity between Themistius' position and the position of the De intellectu quoted above, p. 22,
since according to both, the active intellect joins the potential human intellect at the beginning of
the latter's development.
103
Themistius, Paraphrase of the De anima 100.
104
Ibid. 98-99.

Greek and Arabic Antecedents

27

Aristotle in the human soul: The active intellect is in itself one, but it breaks up and
enters different human subjects, just as natural light comes from a single source and
breaks up in the different subjects receiving it.105
Themistius deploys the other Aristotelian analogy too and describes the active
intellect as standing to the potential intellect as "art" stands to "matter." He appends
a qualification, however: Art and the artisan remain outside the matter they act
upon, whereas the active intellect "enters into the potential intellect through and
through."106 Then Themistius pursues the comparison of the human potential
intellect with matter along a different line. The several faculties of the soul, he
writes, make up a hierarchy in which each level has the status of "matter" in respect
to the level above it, while the level above is the lower level's "form." The faculty
of "sense perception" serves as matter for the imaginative faculty, the "imagination"
as matter for the "potential intellect," and the potential intellect as matter for the
"active [intellect]." In the last instance, the active intellect "becomes one with" the
potential intellect in the way "matter and form" constitute a single entity. And
unlike the intermediate levels of the soul, which are both matter in respect to what
comes next and form in respect to what precedes, the active intellect is not the
matter of anything else. The active intellect is the soul's form in the "true sense,"
the "final form," the "form of forms," and in it the process culminates.107
The upshot is that the active intellect, or an aspect of the active intellect, enters
the potential human intellect, penetrates it through and through, works from within,
lights up the potential intellect and also casts a light on images stored in the
memory, and becomes the form of the potential intellect. The active intellect is
responsible for the first axioms of thought and perhaps conveys them directly to
man. After the active intellect has joined the human potential intellect, the
compound of the two constructs a corpus of intellectual knowledge. By joining
with the potential intellect and "leading it to actuality" the active intellect "effects the
intellect in habitu, in which universal intelligible thoughts and universal scientific
knowledge reside."108
In early Arabic philosophy, both Kindi's treatise On Intellect and the treatise On
the Soul attributed to Porphyry maintain that a supernal being communicates actual
thought directly to the human intellect. Kindi offers the standard argument for the
existence of an agent that produces human thought: Whenever something has a
certain characteristic potentially, it can only be actualized by something else already
possessing the given characteristic actually; therefore the human soul, which is
potentially in possession of intelligible thought, can be rendered actual only
"through the first intellect."109 But Kindi does not merely conclude that actual
105

Ibid. 103; cf. above, p. 12.
Ibid. 99.
107
Ibid. 99-100. At several points, the Arabic differs slightly from the Greek, and I have
translated the latter.
108
Ibid. 98.
106

l09

Rasa'il al-Kindl (n. 22 above) 356; cf. ibid. 155.

Alfarabi, Avicenna, and Averroes, on Intellect

28

human thought entails an actual intellect as its cause. Actual thought occurs when
the human soul "makes contact [bdshara] with intellect, that is, with forms
containing neither matter nor imagination"; and first intellect is the intellect with
which it makes contact. First intellect "supplies" (mufid) what the human soul
"acquires" (mustafid), and the product is "intellect acquired [mustafad] by the

[human] soul from the first intellect."110 How the human intellect makes contact
with supernal intellect and what role sense perception plays in the process is left
unexplained.
The treatise On the Soul attributed to Porphyry does not articulate a full theory of
intellect but does affirm that thought comes to man directly from a transcendent
source. The treatise distinguishes "material intellect," that is, the potential human

intellect, from "second, psychic [nafsam] intellect," which is shown by the context

to be the human intellect in possession of actual thought111; other writers use the
term second intellect in a similar sense.112 "Psychic intellect" is "identical with the
[transcendent] first intellect when they are in the upper world . .. but is different
from it [from the transcendent intellect] when it [the psychic intellect] appears in the
body through the medium of the soul."113 The brief treatise, annoyingly, also uses
an alternative terminology and states that human "intellect," with no further
qualification, comes "from" the "intelligible world" and serves as "form" of the
human soul.114 Since, however, intelligible world is an appellation for the
Neoplatonic cosmic Intellect,115 the statement may be harmonized with the previous
quotation as follows: Actual human thought consists in a form that comes to the
human soul from the transcendent first intellect, also called intelligible world;
when the form is still in first intellect, the two are identical; but when manifested in
the human soul, the form from above becomes distinct from first intellect and is
called second psychic intellect. The treatise On the Soul further states that the
human material intellect can never think without the aid of the "estimative faculty"
(wahtn), a physical faculty of the soul.116 That statement can be integrated with the
others by understanding that when the material intellect contemplates perceptions
presented to it by the estimative faculty of the soul, it prepares itself to receive actual
intellectual thought from the transcendent Intellect. Avicenna will take a position
along those lines.
110

Ibid. 355-56.
Kutsch (n. 55 above) 268, §§3,4.
112
Ibn Gabirol (n. 58 above) 5, §34; Altmann and Stern (n. 56 above) 36. Other senses of
second intellect appear in the long version of the Theology of Aristotle, cited by. S. Stern, "Ibn
Hasday's Neoplatonist," Oriens 13 (1961) 88, 91-92; and in Alfarabi, Risalafi al-cAql, ed. M.
Bouyges (Beirut 1938) 19. Rasa'il al-Kindl 354, also uses the term, but the sense is unclear.
113
Kutsch 268, §4.
114
Ibid. §2.
115
Plotinus, Enneads 5.9.9; E. Zeller, Die Philosophie der Griechen 3.2, 5th ed. (Leipzig
1923) 584-87.
116
Kutsch 268, §3.
111

Greek and Arabic Antecedents

29

Here we have seen that a standard argument developed for assuming a cause of the
actualization of the human intellect: Whenever something passes from potentiality
to actuality, the passage to actuality is effected by an agent that itself already actually
possesses the characteristic in question; the passage of the human potential intellect
to actuality therefore implies an agent possessing actual thought which brings about
the transition (Plotinus, Themistius, Kindi). If the conclusion should be taken to
mean that the cause of human thought not only already possesses actual thought but
that it consists in such thought, the argument would establish an incorporeal,
transcendent cause (Themistius; the argument is not explicit in Plotinus and Kindi,
although they do have a transcendent cause of human thought).
One explanation of the way in which the transcendent cause effects actual human
thought played on Aristotle's analogy of light. In Themistius' version, which
draws the analogy's implications most clearly, the active intellect both casts a light
on potential thoughts, which are images in the human soul, and also lights up the
potential human intellect; it thereby enables the potential intellect to perceive actual
thoughts and to pass to actuality. Another explanation of the way the transcendent
cause effects actual human thought represented the transcendent cause as directly
furnishing either all human thoughts (probably Plotinus; Kindi; the text attributed to
Porphyry) or certain basic thoughts (possibly Themistius). In the spirit of the
second explanation, the human soul was described as containing a sort of mirror
that reflects the contents of the transcendent intellect (Plotinus), and thought was
characterized as acquired from the transcendent intellect (Plotinus, Kindi).
Additional motifs encountered here which were to be significant for the Arabic
Aristotelians are these: The active intellect is related to the human potential intellect
as form to matter (Alexander, Plotinus, Themistius); in bringing the human intellect
to actuality, the active intellect enters into man (De intellectu, Themistius);
thoughts that are all together or undifferentiated in the transcendent intellect are
unrolled and become differentiated in the human soul or intellect (Plotinus,
Themistius).

The Active Intellect as a Cause of Existence
One work of Alfarabi's, Avicenna generally, and the early works of Averroes not
only recognized a transcendent cause that leads human intellects to actuality; they
represented the transcendent cause of human thought, the active intellect, as the
cause of the existence of part or all of the sublunar world. In Alfarabi and
Averroes, the active intellect, besides leading the human intellect to actuality,
emanates a range of sublunar natural forms; in Avicenna, the active intellect, which
not merely leads the human intellect to actuality but directly emanates all human
intelligible thoughts upon properly prepared human intellects, emanates both the
matter of the sublunar world and a range of natural forms appearing in sublunar

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30

matter. Neither the active intellect of Alfarabi and Averroes, nor that of Avicenna,
can be documented prior to their appearance in those philosophers. There were,
nevertheless, a number of precedents for tracing both the actualization-of the human
intellect and the existence of part or all of the physical universe to beings standing
above the physical universe on the scale of existence. In at least one of the
instances, the two functions, actualization of the human intellect and responsibility
for the existence of the physical world, had explicitly been combined in a single
transcendent active intellect; the emanation motif was not yet present, however. In
another of the instances, the two functions were traced to the supernal region, and
the existence of the sublunar world was, moreover, seen as the outcome of an
emanative process; but the two functions were not ascribed to the same supernal
substance. In this second instance, distinct, though kindred, cosmic entities
performed functions very much like those that Avicenna was to combine in a single
active intellect.
The work explicitly combining the two functions in a transcendent active intellect
is Alexander's De anima. As was seen, Alexander there identifies Aristotle's active intellect, the cause of human thought, with the First Cause of the universe.117
Unlike Aristotle, who had envisaged a First Cause solely of the universe's
motion,118 Alexander characterizes the First Cause as "cause and principle of the
existence of all other things,"119 which must mean that it is responsible for the very
existence, and not merely the motion, of the universe. His active intellect is
therefore both the cause of actual human thought and the cause, or at least the
ultimate cause, of the existence of everything outside itself.
A different combination of the two functions in the active intellect appears at the
end of the De intellectu, also attributed to Alexander. The section is problematic
even in the original Greek and gets further obscured in the Arabic translation.
Nevertheless, one can see from the Greek that the De intellectu is examining what
it knows to be a Stoic theory. The active intellect is described as a divine, but
corporeal, substance that permeates the matter of the entire universe without ceasing
to perform its own act of thinking. It governs the sublunar world "either by itself
or in cooperation with the "motion ... of the heavens," by combining and
separating the particles of matter from which natural objects are generated. It is
thereby also the "cause [of the existence]"
of the "potential
intellect," a potential human intellect being generated whenever a portion of matter
is blended in such a way that the matter can serve as an "instrument" for thought.
After bringing the potential human intellect into existence, the active intellect leads it

117

Above, p. 13.
Cf. E. Zeller, Die Philosophic der Griechen 2.2, 4th ed. (Leipzig 1921) 379-81; H.
Davidson, Proofs for Eternity, Creation, and the Existence of God, in Medieval Islamic and
Jewish Philosophy (New York 1987) 281-82.
119
Alexander, De anima (n. 1 above) 89.
118

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31

to actuality. Actual human thought is, in fact, simply the divine active intellect's
thinking through the human intellect.120
In the original Greek, the author of the De intellectu—or if the work is composite, the author of the pertinent section in the De intellectu—proceeds to refute
the theory, and in the course of doing so expressly connects it with "the Stoa." The
Arabic blurs the refutation beyond recognition, however, and does not translate
"Stoa" by the standard Arabic term for that school. In the Arabic, the section might
therefore easily be misread as representing the De intellects, and hence
Alexander's, own view.121 Even when misread, the theory differs from the
position of Alexander's De anima. In consonance with its Stoic inspiration, it has
the divine active intellect penetrating the material world; Alexander's De anima, by
contrast, saw the active intellect as transcendent and wholly incorporeal. The
theory, moreover, acknowledges only a divine factor working within, and giving
form to, the matter of the sublunar world, but not a cause of the existence of all
matter, or even sublunar matter; Alexander's De anima spoke of a cause of the
existence of the entire universe, which presumably means all matter and all form.
Still, the theory recorded in the De intellectu provided medieval Arabic readers
with a further instance of the active intellect's serving as both cause of actual human
thought and—by itself or in cooperation with the heavens—the direct cause of all
natural objects in the sublunar world, including the potential human intellect.
Plotinus' system traces to the incorporeal realm, although not to a single
substance in that realm, both the actualization of the human intellect and the
bringing of the physical universe into existence; and several significant threads in
Plotinus would be woven together in a new pattern by the Arabic Aristotelians.
Intellect, the second hypostasis in Plotinus' cosmic hierarchy, has something of the
character of the Aristotelian active intellect and is the source of human intellectual
activity.122 As refracted through the Arabic paraphrases, Plotinus further states that
Intellect is "all things, and all things are in i t . . . . They are in it as [in] their
agent, whereas it is in them as cause."123 "Intellect is ... cause of what is
beneath it."124 That is to say, Intellect is the cause of the existence of Soul, the

third hypostasis in the cosmic hierarchy; it is the incorporeal model of the physical
universe, including the sublunar region125; and it is the agent ultimately, although
not directly, responsible for the existence of the physical universe. What
immediately "engendered matter" is Soul.126 Inasmuch as matter is "only a
recipient," the forms of the four elements—"fire, . . . water, . . . air, . . .
earth"—and of physical beings above the level of the elements must, like matter
l20

De intellectu (n. 2 above) 112-13.
See further, below, p. 282.
122
Above, n. 42.
123Risalafi al-cllm al-Ildhl (n. 94 above) 168 bottom, paralleling Enneads 5.9.6.
124Theology of Aristotle (n. 54 above) 144-15, paralleling Enneads 6.7.3.
125
Cf. Armstrong (n. 42 above) 75.
126
Enneads 1.8.14; 4.3.9. Cf. Zeller (n. 115 above) 603^t.
121

Alfarabi, Avicenna, and Averroes, on Intellect

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itself, come "from another." Their immediate source is, again, Soul, which
transmits what was given it by Intellect.127 "Soul emanates [tufid] its power over

this entire world,... and nothing corporeal... is free of the power of Soul";
"each body obtains of the power and goodness of Soul in accordance with its ability
to receive that power and goodness"; the "goodness" that Soul sends forth is
"form," the underlying recipient of the goodness sent forth being "matter."128
Among the forms bestowed by Soul upon the physical world are human souls, and
a human soul makes its appearance whenever a body is properly prepared for
receiving one.129
Plotinus' Intellect, which was seen to be a direct source of some or all human
intellectual thought, is thus also the ultimate cause of the emanation of the entire
physical universe. His cosmic Soul is the immediate emanating source of the matter
of the universe, including the matter of the sublunar region, and of forms
manifested in matter. In the sublunar world, those forms range from the four
elements to the human soul. As a team, Intellect and Soul are the source of some or
all of human thought, they emanate the matter of the universe, and they emanate
natural forms, each portion of matter receiving the natural form for which it is fit.
Themistius was already seen to construe the cause of actual human thought as a
transcendent active intellect. His Paraphrase of Aristotle's De anima, the work in
which he delineates the active intellect's role in human thought, also makes the
suggestive remark that "the Soul... inserts
[natural] forms
in matter."130 His Paraphrase of Aristotle's Metaphysics, Book 12, has more to

say. The occasion is a passage in Aristotle's Metaphysics which rejects the

Platonic doctrine of Forms on the grounds that "man begets a man." Themistius
comments: The rule that the progenitor always belongs to the same species as the
offspring, that "man is born only from man and the horse from a horse," leaves
unexplained the spontaneous generation of a "kind of hornet" from the "bodies of
dead horses," of "bees . . . from dead cattle," and similar phenomena. To
l27

Risdlafl al-cllm al-Ilahi 168, paralleling Enneads 5.9.3.
l28Theology of Aristotle 78, paralleling Enneads 4.8.6. Cf. Proclus, Elements of Theology
(n. 67 above) Propositions 122 and 140, and Dodds' note to Proposition 140. Liber de causis,
which is an Arabic paraphrase of parts of the Elements of Theology, states: "The First
Cause... emanates goodness upon all things in a single emanation \faid], but each thing
receives of that emanation in accordance with its existence and being.... Goodness and virtues
differ [in the universe] only by reason of the recipient." See Liber de causis, ed. O. Bardenhewer
(Freiburg 1882) 95-96, paralleling Elements of Theology, Proposition 122.
l29
Enneads 4.8.4-6; 4.9.2. The Henry-Schwyzer edition (n. 4 above) has Lewis' English
translation of an unpublished Arabic paraphrase of these sections. In Plotinus, individual souls are
not completely separated from the Universal Soul; cf. Zeller (n. 115 above) 596-97; E. Brehier,
The Philosophy of Plotinus (Chicago 1958) 66-68. For some of the problems that arise in
Plotinus' philosophy regarding the forms of individual objects, see Zeller 581-82; J. Rist,
Plotinus: The Road to Reality (Cambridge 1967) 104ff.; A. Armstrong, "Form, Individual and
Person in Plotinus," reprinted in his Plotinian and Christian Studies (London 1979) chap. 20.
130
Themistius, Paraphrase of De anima (n. 5 above) 115; Arabic translation 211.

Greek and Arabic Antecedents

33

explain spontaneous generation, certain "relationships" must be assumed to have
"been put in nature" and they are what bring forth not only animals that generate
spontaneously but