A History of Mediaeval Jewish Philosophy

by Isaac Husik

The truth is that the soul does not exist before the body. It arises at the same time as, and in connection with body, realizing and actualizing the latter. Seed and sperm have in them the possibility of becoming plant and animal respectively. But they need an agent to bring to actuality what is in them potentially. This agent—an angel or a sphere, or an angel using a sphere as its instrument—bestows forms upon bodies, which take the places of the previous forms the bodies had. The sphere or star produces these forms (or souls) by means of its motions, which motions ultimately go back to the first incorporeal mover, by whose wisdom forms are connected with bodies in order to perfect the former by means of the latter.

Now the human soul has the most important power of all other animals, that of grasping intelligibles or universals. It is also able to discriminate between good and evil in conduct, moral, political and economic. The human soul, therefore, has, it seems, two powers, theoretical and practical. With the former it understands the simple substances, known as angels in the Bible and as "secondary causes" and "separate intelligences" among the philosophers. By this means the soul rises gradually to its perfection. With the practical reason it attends to noble and worthy conduct. All the other powers of the soul must be obedient to the behests of the practical reason. This in turn is subservient to the theoretical, putting its good qualities at the disposition of the speculative reason, and thus helping it to come into closer communion with the simple substances, the angels and God. This is the highest power there is in the world of nature.

We must now show that the rational power in man is neither itself body nor is it a power residing in a corporeal subject. That it is not itself body is quite evident, for we have proved that the lower souls too, those of animals and plants, are not corporeal. But we must show concerning the rational power that it is independent of body in its activity. This we can prove in various ways. One is by considering the object and content of the reason. Man has general ideas or universal propositions. These are not divisible. An idea cannot be divided into two halves or into parts. Reason in action consists of ideas. Now if reason is a power residing in a corporeal subject, it would be divisible like the latter. Take heat as an example. Heat is a corporeal power, i. e., a power residing in a body. It extends through the dimensions of the body, and as the latter is divided so is the former. But this is evidently not true of general ideas, such as that a thing cannot both be and not be, that the whole is greater than its part, and so on. Hence the rational power is independent of body.

Ibn Daud gives several other proofs, taken from Aristotle and Avicenna, to show that reason is independent, but we cannot reproduce them all here. We shall, however, name one more which is found in the "De Anima" of Aristotle and is based on experience. If the reason performed its thinking by means of a corporeal organ like the external senses, the power of knowing would be weakened when confronted with a difficult subject, and would thereby be incapacitated from exercising its powers as before. This is the case with the eye, which is dazzled by a bright light and cannot see at all, or the ear, which cannot hear at all when deafened by a loud noise. But the case of knowledge is clearly different. The more difficult the subject the more is the power of the reason developed in exercising itself therein. And in old age, when the corporeal organs are weakened, the power of reason is strongest.

Although it is thus true that the rational soul is independent of the body, nevertheless it did not exist before the body any more than the lower souls. For if it did, it was either one soul for all men, or there were as many souls as there are individual men. The first is impossible; for the same soul would then be wise and ignorant, good and bad, which is impossible. Nor could the separate souls be different, for being all human souls they cannot differ in essence, which is their common humanity. But neither can they differ in accidental qualities, for simple substances have no accidents. They cannot therefore be either one or many, i. e., they cannot be at all before body.

Nor must we suppose because the reason exercises its thought functions without the use of a corporeal organ that it appears full fledged in actual perfection in the person of the infant. Experience teaches otherwise. The perfections of the human soul are in the child potential. Later on by divine assistance he acquires the first principles of knowledge about which there is no dispute, such as that two things equal to the same thing are equal to each other, that two contrary predicates cannot apply to the same subject at the same time in the same relation, and so on. Some of these are the fundamental principles of mathematics, others of other sciences. Then he progresses further and learns to make premises and construct syllogisms and argue from the known to the unknown. We have thus three stages in the development of the reason. The first potential stage is known as the hylic or potential intellect. The second is known as the actual intellect, and the third is the acquired intellect. If not for the body the person could not make this progress. For without body there are no senses, and without senses he would not see how the wine in the barrel ferments and increases in volume, which suggests that quantity is accident and body is substance. Nor would he learn the distinction between quality and substance if he did not observe a white garment turning black, or a hot body becoming cold. There is need therefore of the body with its senses to lead to a knowledge of the universals. But this knowledge once acquired, the soul needs not the body for its subsequent existence; and as the soul is not a corporeal power, the death of the body does not cause the extinction of the soul.

Some think that because the soul is the form of the body it is dependent upon it and cannot survive it, as no other form survives its substance. But this inference is not valid. For if the human soul is included in the statement that no form survives its matter, we assume what we want to prove, and there is no need of the argument. If it is not as a matter of fact included, because it is the question at issue, its comparison with the other observed cases is simply a matter of opinion and not decisive.

The reader will see that the problem of the rational soul gave Ibn Daud much concern and trouble. The pre-existence of the soul as Plato teaches it did not appeal to him for many reasons, not the least among them being the statement in Genesis (2, 7), "And God breathed into his nostrils the breath of life," which seems to favor the idea of the soul originating with the body; though, to be sure, a harmless verse of this kind would not have stood in his way, had he had reason to favor the doctrine of pre-existence. Immortality was also a dogma which he dared not deny. The arguments against it seemed rather strong. From the doctrine of the soul's origin with the body and its being fitted to the material composition of the latter, would seem to follow the soul's extinction with the death of the body. The same result was apparently demanded by the observation that the intellect develops as the body matures, and that without the senses and their data there would be no intellect at all. The fluctuation of intellectual strength with the state of bodily health would seem to tend to the same end, against the doctrine of immortality. Moreover, the Aristotelian definition of the soul as the entelechy or form of the body, if it applies to the rational faculty as well as to the lower powers, implies necessarily that it is a form like other forms and disappears with the dissolution of its substance. To avoid all these pitfalls Ibn Daud insists upon the incorporeal character of the reason's activity, i. e., its independence of any corporeal organ, and its increasing power in old age despite the gradual weakening of the body. He admits that its development is dependent on the data of sense perception, but insists that this is not incompatible with its freedom from the body when fully developed and perfected. As for its being a form of body, not all forms are alike; and it is not so certain that the rational power is a form of body. Neither the difficulties nor the solution are of Ibn Daud's making. They are as old as Aristotle, and his successors grappled with them as best they could.

There is still the question of the manner of the soul's survival. The same reasons which Ibn Daud brings forward against the possibility of the existence of many souls before the body, apply with equal cogency to their survival after death. If simple substances having a common essence cannot differ either in essence or in accident, the human souls after the death of the body must exist as one soul, and what becomes of individual immortality, which religion promises? Ibn Daud has not a word to say about this, and it is one of the weak points religiously in his system as well as in that of Maimonides, which the critics and opponents of the latter did not fail to observe.

Before leaving the problem of the soul Ibn Daud devotes a word to showing that metempsychosis is impossible. The soul of man is suited to the character of his elemental mixture, which constitutes the individuality of his body. Hence every individual's body has its own peculiar soul. A living person cannot therefore have in him a soul which formerly resided in a different body unless the two bodies are identical in all respects. But in that case it is not transmigration but the re-appearance of the same person after he has ceased to be. But this has never yet happened.