Among the men who devoted themselves to philosophical investigation in the century and a half after Maimonides's
death, the greatest and most independent was without doubt Levi ben Gerson or Gersonides, as he is also called. There
were others who were active as commentators, translators and original writers, and who achieved a certain fame, but
their work was too little original to merit more than very brief notice in these pages. Isaac Albalag[331a] (second half of
thirteenth century) owes what reputation he enjoys to the boldness with which he enunciated certain doctrines, such as
the eternity of the world and particularly the notion, well enough known among the Averroists of the University of Paris at
that time and condemned by the Church, but never before announced or defended in Jewish philosophy—the so-called
doctrine of the twofold truth. This was an attitude assumed in self-defence, sincerely or not as the case may be, by a
number of scholastic writers, who advanced philosophic views at variance with the dogma of the Church. They
maintained that a given thesis might be true and false at the same time, true for philosophy and false for theology, or vice
versa.[332] Shem Tob Falaquera (1225-1290) is a more important man than Albalag. He was a thorough student of the
Aristotelian and other philosophy that was accessible to him through his knowledge of Arabic. Munk's success in
identifying Avicebron with Gabirol (p. 63) was made possible by Falaquera's translation into Hebrew of extracts from the
"Fons Vitæ." Of great importance also is Falaquera's commentary of Maimonides's "Guide," which, with that of Moses of
Narbonne (d. after 1362), is based upon a knowledge of Arabic and a thorough familiarity with the Aristotelian philosophy
of the Arabs, and is superior to the better known commentaries of Shemtob, Ephodi, and Abarbanel. Falaquera also
wrote original works of an ethical and philosophical character.
Joseph Ibn Caspi (1297-1340) is likewise a meritorious figure as a commentator of Maimonides and as a philosophical
exegete of Scripture. But none of these men stands out as an independent thinker with a strong individuality, carrying
forward in any important and authoritative degree the work of the great Maimonides. Great Talmudic knowledge, which
was a necessary qualification for national recognition, these men seem not to have had; and on the other hand none of
them felt called upon or able to make a systematic synthesis of philosophy and Judaism in a large way.
Levi ben Gerson (1288-1344) was the first after Maimonides who can at all be compared with the great sage of Fostat.
He was a great mathematician and astronomer; he wrote supercommentaries on the Aristotelian commentaries of
Averroes, who in his day had become the source of philosophical knowledge for the Hebrew student; he was thoroughly
versed in the Talmud as his commentary on the Pentateuch shows; and he is one of the recognized Biblical exegetes of
the middle ages. Finally in his philosophical masterpiece "Milhamot Adonai" (The Wars of the Lord), [333] he undertakes
to solve in a thoroughly scholastic manner those problems in philosophy and theology which Maimonides had either not
treated adequately or had not solved to Gersonides's satisfaction. That despite the technical character and style of the
"Milhamot," Gersonides achieved such great reputation shows in what esteem his learning and critical power were held
by his contemporaries. His works were all written in Hebrew, and if he had any knowledge of Arabic and Latin it was very
limited, too limited to enable him to make use of the important works written in those languages.[334] His fame extended
beyond the limits of Jewish thought, as is shown by the fact that his scientific treatise dealing with the astronomical
instrument he had discovered was translated into Latin in 1377 by order of Pope Clement VI, and his supercommentaries
on the early books of the Aristotelian logic were incorporated, in Latin translation, in the Latin editions of Aristotle and
Averroes of the 16th century.[335]
Levi ben Gerson's general attitude to philosophical study and its relation to the content of Scripture is the same as had
become common property through Maimonides and his predecessors. The happiness and perfection of man are the
purpose of religion and knowledge. This perfection of man, or which is the same thing, the perfection of the human soul,
is brought about through perfection in morals and in theoretical speculation, as will appear more clearly when we discuss
the nature of the human intellect and its immortality. Hence the purpose of the Bible is to lead man to perfect himself in
these two elements—morals and science. For this reason the Law consists of three parts. The first is the legal portion of
the Law containing the 613 commandments, mandatory and prohibitive, concerning belief and practice. This is
preparatory to the second and third divisions of the Pentateuch, which deal respectively with social and ethical conduct,
and the science of existence. As far as ethics is concerned it was not practicable to lay down definite commandments
and prohibitions because it is so extremely difficult to reach perfection in this aspect of life. Thus if the Torah gave
definite prescriptions for exercising and controlling our anger, our joy, our courage, and so on, the results would be very
discouraging, for the majority of men would be constantly disobeying them. And this would lead to the neglect of the
other commandments likewise. Hence the principles of social and ethical conduct are inculcated indirectly by means of
narratives exemplifying certain types of character in action and the consequences flowing from their conduct. The third
division, as was said before, contains certain teachings of a metaphysical character respecting the nature of existence.
This is the most important of all, and hence forms the beginning of the Pentateuch. The account of creation is a study in
the principles of philosophical physics.[336]
As to the relations of reason and belief or authority, Levi ben Gerson shares in the optimism of the Maimonidean school
and the philosophic middle age generally, that there is no opposition between them. The priority should be given to
reason where its demands are unequivocal, for the meaning of the Scriptures is not always clear and is subject to
interpretation.[337] On the other hand, after having devoted an entire book of his "Milhamot" to a minute investigation of
the nature of the human intellect and the conditions of its immortality, he disarms in advance all possible criticism of his
position from the religious point of view by saying that he is ready to abandon his doctrine if it is shown that it is in
disagreement with religious dogma. He developed his views, he tells us, because he believes that they are in agreement
with the words of the Torah. [338] This apparent contradiction is to be explained by making a distinction between the
abstract statement of the principle and the concrete application thereof. In general Levi ben Gerson is so convinced of
man's prerogative as a rational being that he cannot believe the Bible meant to force upon him the belief in things which
are opposed to reason. Hence, since the Bible is subject to interpretation, the demands of the reason are paramount
where they do not admit of doubt. On the other hand, where the traditional dogma of Judaism is clear and outspoken, it is
incumbent upon man to be modest and not to claim the infallibility of direct revelation for the limited powers of logical
inference and deduction.
We must now give a brief account of the questions discussed in the "Milhamot Adonai." And first a word about
Gersonides's style and method. One is reminded, in reading the Milhamot, of Aristotle as well as Thomas Aquinas. There
is no rhetoric and there are no superfluous words. All is precise and technical, and the vocabulary is small. One is
surprised to see how in a brief century or so the Hebrew language has become so flexible an instrument in the
expression of Aristotelian ideas. Levi ben Gerson does not labor in the expression of his thought. His linguistic instrument
is quite adequate and yields naturally to the manipulation of the author. Gersonides, the minute logician and analyst, has
no use for rhetorical flourishes and figures of speech. The subject, he says, is difficult enough as it is, without being
made more so by rhetorical obscuration, unless one intends to hide the confusion of one's thought under the mask of fine
writing.[339] Like Aristotle and Thomas Aquinas, he gives a history of the opinions of others in the topic under discussion,
and enumerates long lists of arguments pro and con with rigorous logical precision. The effect upon the reader is
monotonous and wearisome. Aristotle escapes this by the fact that he is groping his way before us. He has not all his
ideas formulated in proper order and form ready to deliver. He is primarily the investigator, not the pedagogue, and the
brevity and obscurity of his style pique the ambitious reader and spur him on to puzzle out the meaning. Not so Thomas
Aquinas and the scholastics generally. As the term scholastic indicates, they developed their method in the schools.
They were expositors of what was ready made, rather than searchers for the new. Hence the question of form was an
important one and was determined by the purpose of presenting one's ideas as clearly as may be to the student. Add to
this that the logic of Aristotle and the syllogism was the universal method of presentation and the monotony and
wearisomeness becomes evident. Levi ben Gerson is in this respect like Aquinas rather than like Aristotle. And he is the
first of his kind in Jewish literature. Since the larger views and problems were already common property, the efforts of
Gersonides were directed to a more minute discussion of the more technical details of such problems as the human
intellect, prophecy, Providence, creation, and so on. For this reason, too, it will not be necessary for us to do more than
give a brief résumé of the results of Gersonides's lucubrations without entering into the really bewildering and hair-
splitting arguments and distinctions which make the book so hard on the reader.
We have already had occasion in the Introduction (p. xxxvi) to refer briefly to Aristotle's theory of the intellect and the
distinction between the passive and the active intellects in man. The ideas of the Arabs were also referred to in our
treatment of Judah Halevi, Ibn Daud and Maimonides (pp. 180 f., 213 f., 282). Hillel ben Samuel, as we saw (p. 317 ff.),
was the first among the Jews who undertook to discuss in greater detail the essence of the three kinds of intellect,
material, acquired and active, as taught by the Mohammedan and Christian Scholastics, and devoted some space to the
question of the unity of the material intellect. Levi ben Gerson takes up the same question of the nature of the material
intellect and discusses the various views with more rigor and minuteness than any of his Jewish predecessors. His chief
source was Averroes. The principal views concerning the nature of the possible or material intellect in man were those
attributed to Alexander of Aphrodisias, the most important Greek commentator of Aristotle (lived about 200 of the
Christian Era), Themistius, another Aristotelian Greek commentator who lived in the time of Emperor Julian, and
Averroes, the famous Arabian philosopher and contemporary of Maimonides. All these three writers pretended to
expound Aristotle's views of the passive intellect rather than propound their own. And Levi ben Gerson discusses their
ideas before giving his own.
Alexander's idea of the passive intellect in man is that it is simply a capacity residing in the soul for receiving the
universal forms of material things. It has no substantiality of its own, and hence does not survive the lower functions of
the soul, namely, sensation and imagination, which die with the body. This passive intellect is actualized through the
Active Intellect, which is not a part of man at all, but is identified by Alexander with God. The Active Intellect is thus pure
form and actuality, and enables the material or possible intellect in man, originally a mere potentiality, to acquire general
ideas, and thus to become an intellect with a content. This is called the actual or acquired intellect, which though at first
dependent on the data of sense, may succeed later in continuing its activity unaided by sense perception. And in so far
as the acquired intellect thinks of the purely immaterial ideas and things which make up the content of the divine intellect
(the Active Intellect), it becomes identified with the latter and is immortal. The reason for supposing that the material
intellect in man is a mere capacity residing in the soul and not an independent substance is because as having the
capacity to receive all kinds of forms it must itself not be of any form. Thus in order that the sense of sight may receive all
colors as they are, it must itself be free from color. If the sight had a color of its own, this would prevent it from receiving
other colors. Applying this principle to the intellect we make the same inference that it must in itself be neutral, not
identified with any one idea or form, else this would color all else knocking for admission, and the mind would not know
things as they are. Now a faculty which has no form of its own, but is a mere mirror so to speak of all that may be
reflected in it, cannot be a substance, and must be simply a power inherent in a substance and subject to the same fate
as that in which it inheres. This explains the motive of Alexander's view and is at the same time a criticism of the doctrine
of Themistius.
This commentator is of the opinion that the passive intellect of which Aristotle speaks is not a mere capacity inherent in
something else, but a real spiritual entity or substance independent of the lower parts of the soul, though associated with
them during the life of the body, and hence is not subject to generation and destruction, but is eternal. In support of this
view may be urged that if the passive intellect were merely a capacity of the lower parts of the soul, we should expect it
to grow weaker as the person grows older and his sensitive and imaginative powers are beginning to decline; whereas
the contrary is the case. The older the person the keener is his intellect. The difficulty, however, remains that if the
human intellect is a real substance independent of the rest of the soul, why is it that at its first appearance in the human
being it is extremely poor in content, being all but empty, and grows as the rest of the body and the soul is developed?
To obviate these difficulties, Averroes in his commentary on the De Anima of Aristotle practically identifies (according to
Levi ben Gerson's view of Averroes) the material intellect with the Active Intellect. The Active Intellect according to him is
neither identical with the divine, as Alexander maintains, nor is it a part of man, as Themistius and others think, but is the
last of the separate Intelligences, next to the spiritual mover of the lunar sphere. It is a pure actuality, absolutely free from
matter, and hence eternal. This Active Intellect in some mysterious manner becomes associated with man, and this
association results in a temporary phase represented by the material intellect. As a result of the sense perceptions,
images of the external objects remain in the imagination, and the Active Intellect takes hold of these images, which are
potentially universal ideas, and by its illumination produces out of them actual ideas and an intellect in which they reside,
the material intellect. The material intellect is therefore the result of the combination of the Active Intellect with the
memory images, known as phantasmata (φαντάσματα), in the human faculty of imagination. So long as this association
exists, the material intellect receives the intelligible forms as derived from the phantasmata, and these forms are
represented by such ideas as "all animal is sensitive," "all man is rational," i. e., ideas concerning the objects of this
world. This phase of man's mind ceases when the body dies, and the Active Intellect alone remains, whose content is
free from material forms. The Active Intellect contemplates itself, a pure intelligence. At the same time it is possible for
man to identify himself with the Active Intellect as he acquires knowledge in the material intellect, for the Active Intellect is
like light which makes the eye see. In seeing, the eye not merely perceives the form of the external object, but indirectly
also receives the light which made the object visible. In the same way the human soul in acquiring knowledge as implicit
in its phantasmata, at the same time gets a glimpse of the spiritual light which converted the phantasma into an explicit
idea (cf. above, p. 320). When the soul in man perfects itself with all the knowledge of this world it becomes identified
with the Active Intellect, which may be likened to the intellect or soul of the corporeal world.
In this combination of the views of Alexander and Themistius Averroes succeeds in obviating the criticisms levelled at the
two former. That the power of the material intellect grows keener with age though the corporeal organs are weaker,
supports Averroes's doctrine as against Alexander, to whom it is a mere capacity dependent upon the mixture of the
elements in the human body. But neither is he subject to the objection applying to Themistius's view, that a real
independent entity could scarcely be void of all forms and a mere receptacle. For the material intellect as it really is in
itself when not in combination with the human body is not a mere receptacle or empty potentiality. It is the Active Intellect,
which combines in itself all immaterial forms and thinks them as it thinks itself. It is only in its individualized aspect that it
becomes a potential intellect ready to receive all material forms.
But what Averroes gains here he loses elsewhere. There are certain considerations which are fatal to his doctrine. Thus
it would follow that theoretical studies which have no practical aim are useless. But this is impossible. Nature has put in
us the ability as well as the desire to speculate without reference to practical results. The pleasure we derive from
theoretical studies is much greater than that afforded by the practical arts and trades. And nature does nothing in vain.
Theoretical studies must therefore have some value. But in Averroes's theory of the material intellect they have none. For
all values may be divided into those which promote the life of the body and those which lead to the final happiness of
man. The former is clearly not served by those theoretical speculations which have no practical aim. On the contrary,
they hinder it. Deep students of the theoretical sciences forego all bodily pleasures, and often do without necessities. But
neither can there be any advantage in theoretical speculation for ultimate human happiness. For human happiness
according to Averroes (and he is in a sense right, as we shall see later) consists in union with the Active Intellect. But this
union takes place as a matter of course according to his theory at the time of death, whether a man be wise or a fool. For
the Active Intellect then absorbs the material.
Another objection to Averroes's theory is the following. If the material intellect is in essence the same as the Active
Intellect, it is a separate, immaterial substance, and hence is, like the Active Intellect, one. For only that which has matter
as its substratum can be quantitatively differentiated. Thus A is numerically different from B, though A and B are both
men (i. e., qualitatively the same), because they are corporeal beings. Forms as such can be differentiated qualitatively
only. Horse is different from ass in quality. Horse as such and horse as such are the same. It follows from this that the
material intellect, being like the Active Intellect an immaterial form, cannot be numerically multiplied, and therefore is one
only. But if so, no end of absurdities follows. For it means that all men have the same intellect, hence the latter is wise
and ignorant at the same time in reference to the same thing, in so far as A knows a given thing and B does not know it.
It would also follow that A can make use of B's sense experience and build his knowledge upon it. All these inferences
are absurd, and they all follow from the assumption that the material intellect is in essence the same as the Active
Intellect. Hence Averroes's position is untenable.[340]
Gersonides then gives his own view of the material intellect, which is similar to that of Alexander. The material intellect is
a capacity, and the prime matter is the ultimate subject in which it inheres. But there are other powers or forms inhering
in matter prior to the material intellect. Prime matter as such is not endowed with intellect, or all things would have human
reason. Prime matter when it reaches the stage of development of the imaginative faculty is then ready to receive the
material intellect. We may say then that the sensitive soul, of which the imaginative faculty is a part, is the subject in
which the material intellect inheres. The criticism directed against Alexander, which applies here also, may be answered
as follows. The material intellect is dependent upon its subject, the sensitive soul, for its existence only, not for the
manner of receiving its knowledge. Hence the weakening or strengthening of its subject cannot affect it directly at all.
Indirectly there is a relation between the two, and it works in the reverse direction. When the sensitive powers are
weakened and their activities diminish, there is more opportunity for the intellect to monopolize the one soul for itself and
increase its own activity, which the other powers have a tendency to hinder, since the soul is one for all these contending
powers. It follows of course that the material intellect in man is not immortal. As a capacity of the sensitive soul, it dies
with the latter. What part of the human soul it is that enjoys immortality and on what conditions we shall see later. But
before we do this, we must try to understand the nature of the Active Intellect.[341]
We know now that the function of the Active Intellect is to actualize the material intellect, i. e., to develop the capacity
which the latter has of extracting general ideas from the particular memory images (phantasmata) in the faculty of
imagination, so that this capacity, originally empty of any content, receives the ideas thus produced, and is thus
constituted into an actual intellect. From this it follows that the Active Intellect, which enables the material intellect to form
ideas, must itself have the ideas it induces in the latter, though not necessarily in the same form. Thus an artisan, who
imposes the form of chair upon a piece of wood, must have the form of chair in his mind, though not the same sort as he
realizes in the wood. Now as all the ideas acquired by the material intellect constitute one single activity so far as the end
and purpose is concerned (for it all leads to the perfection of the person), the agent which is the cause of it all must also
be one. Hence there are not many Active Intellects, each responsible for certain ideas, but one Intellect is the cause of all
the ideas realized in the material intellect. Moreover, as this Active Intellect gives the material intellect not merely a
knowledge of separate ideas, but also an understanding of their relations to each other, in other words of the systematic
unity connecting all ideas into one whole, it follows that the Active Intellect has a knowledge of the ideas from their
unitary aspect. In other words, the unity of purpose and aim which is evident in the development of nature from the prime
matter through the forms of the elements, the plant soul, the animal soul and up to the human reason, where the lower is
for the sake of the higher, must reside as a unitary conception in the Active Intellect.
For the Active Intellect has another function besides developing the rational capacity in man. We can arrive at this insight
by a consideration undertaken from a different point of view. If we consider the wonderful and mysterious development of
a seed, which is only a piece of matter, in a purposive manner, passing through various stages and producing a highly
complicated organism with psychic powers, we must come to the conclusion, as Aristotle does, that there is an intellect
operating in this development. As all sublunar nature shows a unity of purpose, this intellect must be one. And as it
cannot be like one of its products, it must be eternal and not subject to generation and decay. But these are the
attributes which, on grounds taken from the consideration of the intellectual activity in man, we ascribed to the Active
Intellect. Hence it is the Active Intellect. And we have thus shown that it has two functions. One is to endow sublunar
nature with the intelligence and purpose visible in its processes and evolutions; the other is to enable the rational power
in man to rise from a tabula rasa to an actual intellect with a content. From both these activities it is evident that the
Active Intellect has a knowledge of sublunar creation as a systematic unity.
This conception of the Active Intellect, Levi ben Gerson says, will also answer all the difficulties by which other
philosophers are troubled concerning the possibility of knowledge and the nature of definition. The problems are briefly
these. Knowledge concerns itself with the permanent and universal. There can be no real knowledge of the particular, for
the particular is never the same, it is constantly changing and in the end disappears altogether. On the other hand, the