A History of Mediaeval Jewish Philosophy

by Isaac Husik

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.