Soul in Islamic Philosophy
SHAMS C. INATI
The discussion of the human soul, its existence, nature, ultimate objective and eternity, occupies a highly important position in Islamic philosophy and forms its main focus. For the most part Muslim philosophers agreed, as did their Greek predecessors, that the soul consists of non-rational and rational parts. The non-rational part they divided into the plant and animal souls, the rational part into the practical and the theoretical intellects. All believed that the non-rational part is linked essentially to the body, but some considered the rational part as separate from the body by nature and others that all the parts of the soul are by nature material. The philosophers agreed that, while the soul is in the body, its non-rational part is to manage the body, its practical intellect is to manage worldly affairs, including those of the body, and its theoretical intellect is to know the eternal aspects of the universe. They thought that the ultimate end or happiness of the soul depends on its ability to separate itself from the demands of the body and to focus on grasping the eternal aspects of the universe. All believed that the non-rational soul comes into being and unavoidably perishes. Some, like al-Farabi, believed that the rational soul may or may not survive eternally; others, like Ibn Sina, believed that it has no beginning and no end; still others, such as Ibn Rushd, believed that the soul with all its individual parts comes into existence and is eventually destroyed.
1-The existence of the soul
All Muslim philosophers concerned themselves with the subject of the soul. The most detailed and most important works on this subject are those of al-Kindi, al-Farabi, Ibn Sina and Ibn Rushd. Muslim philosophers recognized that the first issue, that confronts the human mind with regard to the soul is its existence. That is why, at the very beginning of his inquiry about the soul inal-Shifa’(Healing), Ibn Sina asserts that we infer the existence of the soul from the fact that we observe bodies that perform certain acts with some degree of will. These acts are exemplified in taking nourishment, growing, reproducing, moving and perceiving. Since these acts do not belong to the nature of bodies, for this nature is devoid of will, they must belong to a principle they have other than bodies. This principle is what is called ‘soul’.
This argument is intended to prove the existence of the animal soul, which includes the plant soul. The soul is the source of acts performed by the will, not inasmuch as it is ‘a substance’ (an independent entity), but inasmuch as it is ‘the principle of such acts’. The rational soul, on the other hand, need not look outside itself to infer its existence. It is aware of its existence with immediacy, that is, without any instruments. Ibn Sina’s example of the suspended man is intended to prove that the rational soul is aware of itself apart from any body. His argument boils down to the view that, even if the adult rational soul is not aware of anything material, not even its body, it remains aware of its own existence.
2-The nature of the soul
While Islam made it incumbent on Muslim philosophers to occupy themselves extensively with the study of the soul and to make certain statements that in some cases appear consistent with Islamic beliefs, Greek philosophy had the upper hand in forming the real convictions of Muslim philosophers with regard to the nature of the soul. Unless otherwise specified, reference to :he soul here is limited to the terrestrial soul to the exclusion of the celestial one, since Muslim philosophers concerned themselves primarily with the former. It must be pointed out at the outset that ‘soul’.(nafs)was used in more than one sense in Islamic philosophy; the term was used to refer to the plant or vegetative part of a living being, the animal or sensitive part, the rational part and finally the totality of all three parts. The first two are the non-rational soul and the totality is the human soul. To add to the confusion, ‘human soul’ is used only in the sense of this fourth type of soul. The plant, animal and; rational souls are also called powers or parts of the; soul. Only from the context can one understand, whether a Muslim philosopher was using ‘soul’ in the broad sense to mean the human soul (the totality of the parts of the soul), or in the narrow sense to mean a specific part of the human soul.
Inasmuch as it has a certain relation to a body, the soul is a form for that body, that is, the perfection of that body. It is a form because a natural body is composed of matter and form, which in the case of animals are body and soul. Since it has been shown that the soul is the source of will and therefore is not matter, it remains a form. Perfection is of two types, primary and secondary. A primary perfection is what makes a thing actually a species, as shape does for the sword, or a genus as sensation and-movement do for animals. A secondary perfection is an act necessitated by the nature of the species or genus, such as cutting for the sword and touching for animal. The soul is a primary perfection of a natural body capable of performing the secondary perfections necessitated by this primary perfection. Together with its body, the soul constitutes a material substance. This substance can be the subject of plant, animal or human life.
The soul is a perfection inasmuch as it makes a natural body into a plant, an animal or a rational being. However, to define the soul as a perfection does not give us a clue as to what the soul is in itself, but only inasmuch as it has a relation to the body. The body is, therefore, an essential element in the definition of the soul. Without relating to a body, the thing we call ‘soul’ is not a soul and does not require the body as an essential part of its definition. Note, however, that in spite of this assertion, perhaps for the lack of any better term, Muslim philosophers use ‘soul’ also to refer to the rational soul after it separates from the body and reaches a complete state of purity from matter.
In its first or lowest stages of relating to the body, the soul is the plant soul, which is a primary perfection for an organic natural body inasmuch as this body can take nourishment, grow and reproduce. The plant soul is the power human beings and other animals share with plants. If the body with a soul is an animal, the soul develops into the animal soul, which is a primary perfection for an organic natural body inasmuch as this body has sensation and movement through will. While this soul includes the plant soul, it has also a sensitive power and a locomotive one. The sensitive power has both external and internal senses. The external senses are, in priority of existence, touch, taste, smell, hearing and sight. The first three are said to be necessary for survival and the last two for well being. InTalkhis kitab an-nafs(Middle Commentary on Aristotle’sOn the Soul),IBN RUSHD (3) asserts that the five external senses may be in potentiality, as in infancy and sleep, or in actuality, as in daily seeing or hearing. He also argues that there cannot be any external sense other than these five because there would be no function for it, since there is no external sensation other than the objects of the five senses mentioned above. Most Muslim philosophers mention three types of internal senses: common sense, imagination and memory. IBN SINA (3) enumerates five internal senses: common sense, representational power, imagination, estimative power and memory. On the whole, the philosophers agree on the function of the common sense, imagination and memory; the function that Ibn Sina limits to the representational and estimative powers, other Muslim philosophers allocate to the imagination.
The common sense is an internal power in which all the objects of the external senses are collected. Contrary to the external senses, which can grasp only one type of sensation, as sight grasps light and hearing grasps sound, the common sense can grasp all external sensations, such as that honey is of such and such a colour, texture and smell. The representational power preserves the sensations of the common sense even after sensible things disappear. The imagination selects at will to combine some of the objects of the representational power with each other and to separate the rest. It makes its judgment about external things, but in the absence of these things. That is why it functions best when the external senses, which represent external things, are not at work, as in sleep. Ibn Rushd points out that animals such as worms and flies that do not act except in the presence of sensible things are devoid of imagination. The imagination is called such inasmuch as it is an animal instrument; it is called cognitive inasmuch as it is a rational instrument. The estimative power grasps non-sensible notions of sensible things, such as the sheep’s notion that the wolf is to be avoided. This notion is about a sensible thing but is not grasped through the external senses, as is the colour or shape of a wolf. Memory preserves the notions of the estimative power. The imagination acts on the objects of memory in the same way it acts on those of the representational powers. Like the objects of the external senses, those of the internal senses are particular and material. The difference is that they can be experienced in the absence of external things and are to some degree abstracted from matter.
The locomotive power branches into that which causes movement and that which actually moves. The former, the desiderative power, subdivides into the appetitive and the irascible. The appetitive causes movement toward what is imagined to be necessary or beneficial in the pursuit of pleasure. The irascible causes avoidance of what is imagined to be harmful or an impediment in the pursuit of dominance. The power that actually moves uses the nerves to relax the muscles at the demands of the appetitive power or tighten them at the demands of the irascible one.
3- The rational soul
The rational soul, which is defined as a primary perfection for an organic natural body inasmuch as this body can act by rational choice and grasp the universals, is divided into the practical and the theoretical intellects. The practical intellect seeks knowledge in order to act in accordance with the good in its individual body, its family and its state. It must, therefore, know the principles for properly managing the body, the family and the state, that is, ethics, home management and politics. The practical intellect is the rational soul turning its face downward. The function of the theoretical intellect is to know just for the sake of having the universals (the realities or natures of things). Some of these natures, such as God and the intellect, cannot attach to movement; knowledge of them is metaphysics. Other natures, such as unity, can attach to movement but do not; knowledge of them is mathematics. Still other natures, such as humanity and squareness, can attach to movement either in reality and thought, such as humanity, or in reality but not in thought, such as squareness. Knowledge of these is physics.
The theoretical intellect is the rational soul with its face upward. The practical intellect looks up to the theoretical one and moves its body accordingly. In this, the practical intellect is similar to :the celestial soul that looks up to the intellect of its sphere and moves its sphere accordingly. Thus, like .the celestial soul, the practical intellect is the link between intellect as such and matter.
On the whole, Muslim philosophers followed al-Kindi’s division of the theoretical intellect into the material intellect(al-‘aql al-hayulant),the habitual intellect(al-‘agl bil-malaka),the actual intellect(al-‘aql bi’!-fi’band the acquired intellect’ (al-‘aql al-mustafad). The material intellect is a blank slate with the potentiality for grasping the intelligible forms or universals. Ibn Sina points out that it is referred to as material, not because it is actually material but because it resembles matter in accepting the form. The habitual intellect grasps the universals, as one acquires the skill to write; in other words, this intellect has the ability to use the universals but does not always do so. The actual intellect grasps the universals in actuality and is always ready to use them. While Muslim philosophers differed slightly with regard to their accounts of the acquired intellect, their general view is that it is the highest human state, the point of contact with the divine, the agent intellect (the intelligence of the moon, the lowest celestial intellect), which makes it possible for the theoretical intellect to acquire the universals in the purest form (see EPISTEMOLOGY IN ISLAMIC PHILOSOPHY 4).
4- The ultimate objective of the soul
AL-FARABI asserts that even though the soul is of different parts, it is a unity with all its parts working for one final end, happiness. While the plant soul, for example, serves a specific function, it also serves the powers that are higher than it in rank, the animal powers. Without nourishment, growth and reproduction, the animal powers cannot perform their necessary functions. Similarly, while the function of the animal powers is to have sensation and movement, by performing this function they also promote the functions of the powers above them, the rational ones. The operations of the animal powers, especially those of the senses, are particularly important for the attainment of the final end. The external senses strip the forms from material objects and convey them to the internal senses. The more they are transferred internally, the less mixed with matter do they become. Since the innermost sense they reach is the imagination, they are there in their purest material existence.
The role of the objects of the imagination is not always clearly defined in Islamic philosophy. Occasionally it is said by somebody like Ibn Sina to be one of preparation for the theoretical intellect to receive the universals from the agent intellect. At other times Ibn Sina, like other Aristotelians such as Ibn Rushd, takes these objects to be the ingredients out of which the universals are made after the last process of purification. It seems, however, that in either case the light of the agent intellect is needed to complete the process. In the former case, this light gives the intelligible forms to the theoretical intellect when this intellect is prepared. In the latter case, it sheds itself on the objects of the imagination, which are then reflected on the theoretical intellect without their matter. Since the theoretical intellect is in its first stages in potentiality, it cannot act on the objects of the imagination directly; hence the need for the agent intellect, which is pure actuality. The role of the practical intellect in all this is to put order into the body. This sets free the theoretical intellect from preoccupation with the body and helps the powers whose function is necessary for theoretical knowledge to function unhampered.
Muslim philosophers adhered to the view that the acquired intellect is one with its objects, for they thought the knower and the known are one, as did their Greek predecessors. This means that the highest human state is one in which unity with the universals or the eternal aspects of the universe is reached. This state is described as happiness because in it eternity, an aspect of the objects of the acquired intellect, is attained.
5- Eternity of the soul
When Muslim philosophers assert that the soul comes into existence simultaneously with the coming into existence of the body, some, such as Ibn Sina (§6), who believe that the rational soul is in essence nonmaterial, are thinking only of the non-rational soul. Others, such as Ibn Rushd (§3), who believe that the rational soul is originally not separate from matter, contend that the whole human soul comes into existence. The latter believe that since the rational soul grasps the universals from particular sensibles, and since such sensibles are material and have a temporal beginning, this soul must also be material and must have a temporal beginning. Those who attribute non-materiality to the essence of the rational soul, such as AL-KINDI and Ibn Sina, assert that this soul pre-exists the body. While all of them agree that the non-rational soul is destroyed after the destruction of the body, they differ with regard to the end of the rational soul.
Al-Kindi and Ibn Sina, for example, strongly adhere to the view that all rational souls are indestructible because by nature they are simple. AL-FARABI reminds us that the reason for eternal existence is the rational soul’s knowledge of the eternal aspects of the universe. From this he draws the conclusion, as did ALEXANDER OF APHRODISIAS before him, that only those rational souls that have this knowledge at their separation from the body are indestructible. Other rational souls are eventually destroyed. Ibn Sina finds in the grasping of the universals the grounds for happiness, not the eternity of the soul. Ibn Rushd seems to hold that only the acquired intellect can be indestructible; but the acquired intellect, he argues (as does his teacher IBN BAJJA), is divine and numerically one in all. Ibn Rushd was attacked for this view because it denies eternal existence of individual souls.