Nothing can move itself. While it is true that the form of a thing determines the kind of motion it shall have, it cannot in itself produce that motion, which can be caused only by an efficient cause from without. The case of animal motions may seem like a refutation of this view, but it is not really so. The soul and the body are two distinct principles in the animal; and it is the soul that moves the body. The reason why a thing cannot move itself is because the thing which is moved is potential with reference to that which the motion is intended to realize, whereas the thing causing the motion is actual with respect to the relation in question. If then a thing moved itself, it would be actual and potential at the same time and in the same relation, which is a contradiction. The Bible, too, hints at the idea that every motion must have a mover by the recurring questions concerning the origin of prophetic visions, of the existence of the earth, and so on. Such are the expressions in Job (38, 36, 37): "Who hath put wisdom in the inward parts?" "Who can number the clouds by wisdom?" In Proverbs (30, 4): "Who hath established all the ends of the earth?" and in many pa.s.sages besides.[234]

The question of infinity is another topic of importance for proving the existence of G.o.d. We proceed as follows: An infinite line is an impossibility. For let the lines _a_------------_b_ be infinite in the _c_------|-----_d_ _e_ directions _b_, _d_. Take away from _cd_ a finite length = _ce_, and pull up the line _ed_ so that _e_ coincides with _c_. Now if _ed_ is equal to _ab_, and _cd_ was also equal to _ab_ by hypothesis, it follows that _ed_ = _cd_, which is impossible, for _ed_ is a part of _cd_. If it is shorter than _cd_ and yet is infinite, one infinite is shorter than another infinite, which is also impossible. The only alternative left is then that _ed_ is finite. If then we add to it the finite part _ce_, the sum, _ce_ + _ed_ = _cd_, will be finite, and _cd_ being equal to _ab_ by hypothesis, _ab_ is also finite. Hence there is no infinite line. If there is no infinite line, there is no infinite surface or infinite solid, for we could in that case draw in them infinite lines. Besides we can prove directly the impossibility of infinite surface and solid by the same methods we employed in line.

We can prove similarly that an infinite series of objects is also an impossibility. In other words, infinite number as an actuality is impossible because it is a contradiction in terms. A number of things means a known number; infinite means having no known number. A series is something that has beginning, middle and end. Infinite means being all middle. We have thus proved that an actual infinite is impossible, whether as extension or number. And the Bible also alludes to the finiteness of the universe in the words of Isaiah (40, 12): "Who hath measured the waters in the hollow of his hand...," intimating that the universe is capable of being measured.

We must prove next that no finite body can have an infinite power.

For let the line _ae_ ------------- be a finite line having an infinite _a_ _b_ _c_ _d_ _e_ power. Divide into the several parts _ab_, _be_, _cd_, _de_, etc. If every one of the parts has an infinite power, _ab_ has an infinite power, _ac_ a greater infinite power, _ad_ a still greater, _ae_ a still greater, and so on. But this is absurd, for there cannot be anything greater than the infinite. It follows then that each of the parts has a finite power; and as the sum of finites is finite, the line _ae_ also has a finite power. All these principles we must keep in mind, for we shall by means of them prove later the existence and incorporeality of G.o.d.[235]

As the concepts of physics are essential for proving the existence of G.o.d, so are the principles of psychology of importance in showing that there are intermediate beings between G.o.d and the corporeal substances of the world. These are called in the Bible angels. The philosophers call them secondary causes.

Accordingly Ibn Daud follows his physical doctrines with a discussion of the soul. There is nothing new in his proof that such a thing as soul exists. It is identical with the deduction of Joseph Ibn Zaddik (_supra_, p. 134). Stone and tree and horse and man are all bodies and yet the last three have powers and functions which the stone has not, _viz._, nutrition, growth and reproduction. Horse and man have in addition to the three powers above mentioned, which they have in common with tree, the powers of sensation and motion and imagination, which plants have not. Finally man is distinguished above all the rest of animal creation in possessing the faculty of intelligence, and the knowledge of art and of ethical discrimination. All these functions cannot be body or the result of body, for in that case all corporeal objects should have all of them, as they are all bodies. We must therefore attribute them to an extra-corporeal principle; and this we call soul. As an incorporeal thing the soul cannot be strictly defined, not being composed of genus and species; but we can describe it in a roundabout way in its relation to the body. He then gives the Aristotelian definition of the soul as "the [first] entelechy of a natural body having life potentially" (_cf._ above, p. x.x.xv).

Like many of his predecessors who treated of the soul, Ibn Daud also finds it necessary to guard against the materialistic theory of the soul which would make it the product of the elemental mixture in the body, if not itself body. This would reduce the soul to a phenomenon of the body, or in Aristotelian terminology, an accident of the body, and would deprive it of all substantiality and independence, not to speak of immortality. How can that which is purely a resultant of a combination of elements remain when its basis is gone? Accordingly Ibn Daud takes pains to refute the most important of these phenomenalistic theories, that of Hippocrates and Galen. Their theory in brief is that the functions which we attribute to the soul are in reality the results of the various combinations of the four elementary qualities, hot, cold, moist, dry. The more harmonious and equable the proportion of their union, the higher is the function resulting therefrom. The difference between man and beast, and between animal and plant is then the difference in the proportionality of the elemental mixture. They prove this theory of theirs by the observation that as long as the mixture is perfect the activities above mentioned proceed properly; whereas as soon as there is a disturbance in the mixture, the animal becomes sick and cannot perform his activities, or dies altogether if the disturbance is very great. The idea is very plausible and a great many believe it, but it is mistaken as we shall prove.

His refutation of the "accident" or "mixture" theory of the soul, as well as the subsequent discussion of the various functions, sensuous and rational, of the tripart.i.te soul, are based upon Ibn Sina's treatment of the same topic, and we have already reproduced some of it in our exposition of Judah Halevi. We shall therefore be brief here and refer only to such aspects as are new in Ibn Daud, or such as we found it advisable to omit in our previous expositions.

His main argument against the materialistic or mechanistic theory of the soul is that while a number of phenomena of the growing animal body can be explained by reference to the form of the mixture in the elementary qualities, not all aspects can be thus explained. Its growth and general formation may be the result of material and mechanical causes, but not so the design and purpose evident in the similarity, to the smallest detail, of the individuals of a species, even when the mixture is not identical. There is no doubt that there is wisdom here working with a purpose. This is soul. There is another argument based upon the visible results of other mixtures which exhibit properties that cannot be remotely compared with the functions we attribute to the soul. The animal and the plant exhibit activities far beyond anything present in the simple elements of the mixture. There must therefore be in animals and plants something additional to the elements of the mixture. This extra thing resides in the composite of which it forms a part, for without it the animal or plant is no longer what it is. Hence as the latter is substance, that which forms a part of it is also substance; for accident, as Aristotle says, is that which resides _in_ a thing but not as forming a part of it.

We have now shown that the soul is substance and not accident. We must still make clear in which of the four senses of the Aristotelian substance the soul is to be regarded. By the theory of exclusion Ibn Daud decides that the soul is substance in the sense in which we apply that term to "form." The form appears upon the common matter and "specifies" it, and makes it what it is, bringing it from potentiality to actuality. It is also the efficient and final cause of the body. The body exists for the sake of the soul, in order that the soul may attain its perfection through the body. As the most perfect body in the lower world is the human body, and it is for the sake of the soul, it follows that the existence of the sublunar world is for the sake of the human soul, that it may be purified and made perfect by science and moral conduct.

While we have proved that soul is not mixture nor anything like it, it is nevertheless true that the kind of soul bestowed upon a given body depends upon the state of the mixture in the elementary qualities of that body. Thus we have the three kinds of soul, vegetative, animal and human or rational. We need not follow Ibn Daud in his detailed descriptions of the functions of the several kinds of soul, as there is little that is new and that we have not already met in Joseph Ibn Zaddik and Judah Halevi. Avicenna (Ibn Sina) is the common source for Halevi and Ibn Daud, and the description of the inner senses is practically identical in the two, with the slight difference that Halevi attributes to the "common sense" the two functions which are divided in Ibn Daud between the common sense and the power of representation.

The soul is not eternal. It was created and bestowed upon body. When a body comes into being, the character of its mixture determines that a soul of a certain kind shall be connected with it. The other alternatives are (1) that the soul existed independently before the body, is then connected with the body and dies with the death of the latter; or (2) it remains after the death of the body. The first alternative is impossible; because if the soul is connected with the body in order to die with it, its union is an injury to the soul, for in its separate existence it was free from the defects of matter. The second alternative is equally impossible; for if the soul was able to exist without the body before the appearance of the latter and after its extinction, of what use is its connection with the body? Far from being of any benefit, its union with the body is harmful to the soul, for it is obliged to share in the corporeal accidents. Divine wisdom never does anything without a purpose.

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 n.o.ble 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 G.o.d. 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 a.s.sistance 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 quant.i.ty 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 a.s.sume 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 G.o.d 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 const.i.tutes 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.

Finally Ibn Daud finds it necessary to defend the Bible against those who criticize the Jews on the ground that there is no mention of the future world and the existence of the soul after death in the Biblical writings. All the rewards and punishments spoken of in the Bible, they say, refer to this world. His answer offers nothing new. Judah Halevi had already tried to account for this phenomenon, besides insisting that altogether devoid of allusion to the future world the Bible is not. Ibn Daud follows in Halevi's footsteps (_cf._ above, p. 170).[236]

Abraham Ibn Daud closes the first, the purely scientific part of his treatise, by a discussion of the heavenly spheres and their motions. In accordance with the view of Aristotle, which was shared by the majority of writers throughout the middle ages, he regards the spheres with their stars as living beings, and their motions as voluntary, the result of will and purpose, and not simply "natural," _i. e._, due to an unconscious force within them called nature. One of his arguments to prove this is derived from the superiority of the heavenly bodies to our own. Their size, their brightness and their continued duration are all evidence of corporeal superiority. And it stands to reason that as the human body, which is the highest in the sublunar world, has a soul that is n.o.bler than that of plant or animal, so the heavenly bodies must be endowed with souls as much superior to the human intellect as their bodies are to the human body. The Bible alludes to this truth in the nineteenth Psalm, "The heavens declare the glory of G.o.d.... There is no speech nor language...." The last expression signifies that they praise G.o.d with the intellect. There are other pa.s.sages in the Bible besides, and particularly the first chapter of Ezekiel, which make it clear that the heavenly bodies are living and intelligent beings; not, to be sure, in the sense of taking nourishment and growing and reproducing their kind and making use of five senses, but in the sense of performing voluntary motions and being endowed with intellect.[237]

We have now concluded our preliminary discussion of the scientific principles lying at the basis of Judaism. And our next task is to study the fundamental doctrines of Jewish theology which form the highest object of knowledge, dealing as they do with G.o.d and his attributes and his revelation. The first thing to prove then is the existence of G.o.d, since we cannot define him. For definition means the designation of the genus or cla.s.s to which the thing defined belongs, whereas G.o.d cannot be put in a cla.s.s. As the essence of a thing is revealed by its definition, we cannot know G.o.d's essence and are limited to a knowledge of his existence.

The principles for this proof we have already given. They are that a thing cannot move itself, and that an actual infinite series is impossible. The argument then proceeds as follows: Nothing can move itself, hence everything that moves is moved by something other than itself. If this is also moving, it must be moved by a third, and so on _ad infinitum_. But an actual infinite series of things moving and being moved is impossible, and unless we ultimately arrive at a first link in this chain, all motion is impossible. Hence there must be a first to account for the motion we observe in the world. This first must not itself be subject to motion, for it would then have to have another before it to make it move, and it would not be the first we supposed it to be. We have thus proved, therefore, the existence of a _primum movens immobile_, a first unmoved mover.

We must now show that this unmoved mover is incorporeal. This we can prove by means of another principle of physics, made clear in the first part. We showed there that a finite body cannot have an infinite power.

But G.o.d is infinite. For, being immovable, his power is not affected by time. Hence G.o.d cannot be body.

This proof, as we said before, is new in Jewish philosophy. In Bahya we found a proof which bears a close resemblance to this one (_cf._ above, p. 87); but the difference is that Bahya argues from being, Ibn Daud from motion. Bahya says if a thing is, some cause must have made it to be, for a thing cannot make itself. As we cannot proceed _ad infinitum_, there must be a first which is the cause of the existence of everything else. The objection here, of course, is that if a thing cannot make itself, how did the first come to be.

The Aristotelian proof of Ibn Daud knows nothing about the origin of being. As far as Aristotle's own view is concerned there is no _temporal_ beginning either of being or of motion. Both are eternal, and so is matter, the basis of all genesis and change. G.o.d is the eternal cause of the eternal motion of the world, and hence of the eternal genesis and dissolution, which const.i.tutes the life of the sublunar world. How to reconcile the idea of eternal time and eternal motion with the doctrine that an actual infinite is impossible we shall see when we treat Maimondes (p. 251). Ibn Daud does not adopt eternity of motion even hypothetically, as Maimonides does. But this merely removes the difficulty one step. For the infinity which is regarded impossible in phenomena is placed in G.o.d. But another more serious objection is the adoption of an Aristotelian argument where it does not suit. For the argument from motion does not give us a creator but a first mover. For Aristotle there is no creator, and his proof is adequate. But for Ibn Daud it is decidedly inadequate. We are so far minus a proof that G.o.d is a creator _ex nihilo_. Ibn Daud simply a.s.serts that G.o.d created matter, but this argument does not prove it. As to the incorporeality of G.o.d Aristotle can prove it adequately from the eternity of motion. If a finite body (and there is no such thing as an infinite body) cannot have an infinite power, G.o.d, whose causing eternal motion argues infinite power, is not a body. Ibn Daud's attempt to prove G.o.d's infinity without the theory of infinite motion on the ground that time cannot affect what is immovable, is decidedly less satisfactory. On the whole then this adoption of Aristotle's argument from motion is not helpful, as it leads to eternity of matter, and G.o.d as the mover rather than the Creator.

Gersonides was frank enough and bold enough to recognize this consequence and to adopt it. We shall see Maimonides's att.i.tude when we come to treat of his philosophy.

Ibn Daud may have been aware of the inadequacy of his argument from motion, and therefore he adds another, based upon the distinction between the "possible existent" and the "necessary existent"--a distinction and an argument due to Alfarabi and Avicenna. A possible existent is a thing whose existence depends upon another, and was preceded by non-existence. It may exist or not, depending upon its cause; hence the name _possible_ existent. A necessary existent is one whose existence is in itself and not derived from elsewhere. It is a necessary existent because its own essence cannot be thought without involving existence. Now the question is, Is there such a thing as a necessary existent, or are all existents merely possible? If all existents are possible, we have an infinite series, every link of which is dependent for its existence upon the link preceding it; and so long as there is no first there is nothing to explain the existence of any link in the chain. We must therefore a.s.sume a first, which is itself not again dependent upon a cause prior to it. This is by definition a necessary existent, which is the cause of the existence of everything else. This proof is compatible with G.o.d as a Creator.

Having shown the existence and incorporeality of G.o.d we must now prove his unity. We shall base this proof upon the idea of the necessary existent. Such an existent cannot have in it any multiplicity; for if it has, its own essence would not be able to keep the elements together, and there would be need of an external agent to do this. But in this case the object would be dependent upon something else, which is incompatible with the idea of a necessary existent.

Nor is it possible there should be two necessary existents; for the necessary existent, we have just shown, must be of the utmost simplicity, and hence cannot have any attribute added to its essence.

Now if there is a second, there must be something by which the first differs from the second, or they are identical. Either the first or the second therefore would not be completely simple, and hence not a necessary existent.

We have thus shown that G.o.d is one both in the sense of simple and in the sense of unique. To have a clear insight into the nature of his unity, we must now show that nothing else outside of G.o.d is really one, though we apply the term one to many things. No one will claim that a collective is one; but neither is an individual really one, for an individual man, for example, consists of many organs. You might think that a h.o.m.ogeneous and continuous elementary ma.s.s like air or water is one. But this is not true either, for everything that is corporeal is composed of matter and form. If then we set aside corporeal objects and aim to find real unity in mathematical ent.i.ties like line and surface, which are not corporeal, we are met with the difficulty that line and surface are divisible, and hence potentially multiple. But neither are the simple intellectual substances, like the angels, true ones; for they are composed of their own possible existence and the necessary existence they acquire from another. The only being therefore that may be a true one is that which is not corporeal and not dependent upon another for its existence.

Considering the question of unity from a different aspect, in its relation, namely, to the thing designated as one, we find that unity never forms the essence of anything called by that name; but is in every case an accident. Thus if it were the essence of man as man that he is one, there could not on the one hand be many men, and on the other there could not also at the same time be one horse, one tree, one stone. In G.o.d his unity cannot be an accident, since as simple he has no accidents. Hence his unity is his essence. And if we examine the matter carefully we find that it is a negative concept. It involves two things.

First, that every other unity involves plurality in some form or another. And second that being unlike anything else, he cannot bear having other things a.s.sociated with him to make the result many, as we can in the case of man. A, for example, is one; and with B, C, and D he becomes many. This is not applicable to G.o.d.[238]

The divine attributes form the next topic we must consider. Here Ibn Daud offers little or nothing that is essentially new. He admits neither essential nor accidental attributes, for either would bring plurality and composition in the nature of G.o.d. The only attributes he admits are negative and relative. When we speak of G.o.d as cause we do not place any special ent.i.ty in his essence, but merely indicate the dependence of things upon him. The truest attributes are the negative, such as that he is not body, that his existence is not dependent upon another, and so on; the only difficulty being that negative attributes, though removing many doubts, do not give us any positive information. All the anthropomorphic attributes in the Bible endowing G.o.d with human functions like sleeping and waking, or ascribing to him human limbs, eyes, ears, hands, feet, etc., must be understood metaphorically. For the Bible itself warns us against corporealizing G.o.d, "Take ye therefore good heed unto yourselves; for ye saw no manner of form on the day that the Lord spake unto you in h.o.r.eb" (Deut. 4, 15). When the Bible speaks of G.o.d's anger and favor, the meaning is that good deeds bring man near to G.o.d and cause happiness which is known as paradise ("Gan Eden"), and bad deeds remove far away from G.o.d and lead to misfortune, called Gehenna. It is like the apparent motion of the trees and the mountains to the traveller, when in reality it is he that is moving. So here G.o.d is said to approach and depart, to be angry with and favor, when in reality it is man who by his deeds comes near to G.o.d or departs far from him. When we a.s.sign many attributes to G.o.d we do not mean that there is any multiplicity in his nature. This cannot be. It is like the case of a man whose eyes are not properly co-ordinated. He sees double when there is only one. So we too suffer from intellectual squinting, when we seem to see many attributes in the one G.o.d.

The most common and most important attributes are the following eight: One, existent, true, eternal, living, knowing, willing, able. It can be easily shown (and Ibn Daud does proceed to show, though we shall not follow him in his details) that all these are at bottom negative. Unity means that there is nothing like him and that he is indivisible. Eternal means he is not subject to change or motion. True means he will never cease existing and that his existence does not come from another, and so on with the rest.

He closes his discussion of the attributes by intimating that he has more to say on this topic, but had better be content with what has been said so far, for a more thorough discussion of these matters in a book might do harm to those who do not understand and interpret the author's words incorrectly. This reminds us of Maimonides's adjuration of the reader to keep what he finds in the "Guide of the Perplexed" to himself and not to spread it abroad. Philosophy clearly was a delicate subject and not meant for intellectual babes, whose intellectual digestion might be seriously disturbed.[239]

We have now concluded our theory of G.o.d and his attributes; and in doing so we made use of principles of physics, such as matter and form, potentiality and actuality, motion and infinity. The next step is to prove the existence and nature of intermediate spiritual beings between G.o.d and the corporeal objects of the superlunar and sublunar worlds, called angels in the Bible, and secondary causes by the philosophers.

For this purpose we shall have to apply the principles we have proved concerning the soul and the motions of the heavenly bodies. We have proved above that the human soul is at first in the child intelligent potentially and then becomes intelligent actually. This requires an agent, in whom the end to which the potential is proceeding is always actual. As the rational soul is neither body nor a corporeal power, this actual agent cannot be either of these, hence it is neither a sphere nor the soul of a sphere, but it must be a simple substance called _Active Intellect_. The prophets call it "Holy Spirit" ("Ruah Ha-Kodesh"). We thus have a proof of the existence of at least one such simple intellectual substance, or angel, the relation of which to the human soul is as that of light to vision. Without light vision is potential, light makes it actual. So the active intellect makes the potential soul actual and gives it first the axioms, which are universally certain, and hence could not have originated by induction from experience.

Similarly we can prove the existence of other simple substances from the motions of the heavenly spheres. We have already shown that the spheres are living beings and endowed with souls. But souls, while causing motion in their bodies are at the same time themselves in a sort of psychic motion. This must be caused by unmoved movers, or intellects, who are also the causes of the souls. To make this difficult matter somewhat clearer and more plausible, we may instance an a.n.a.logy from familiar experience. A ship is made by the shipbuilder, who is its corporeal cause. But there is also an incorporeal cause, likewise a ship, _viz._, the ship in the mind of the shipbuilder. The a.n.a.logy is imperfect, because the incorporeal ship in the mind of the builder cannot produce an actual corporeal ship without the builder employing material, such as wood, iron, etc., and in addition to that expending time and physical exertion on the material. But if he had the power to give the form of a ship to the material as soon as the latter was prepared for it without time and physical manipulation, we should have an instance of what we want to prove, namely, the existence of simple immaterial substances causing forms to emanate upon corporeal existences. This is the nature of the active intellect in its relation to the soul of man, and it is in the same way that the philosophers conceive of the motions of the heavenly spheres. G.o.d is the first unmoved mover. The angels or simple substances stand next to him; and they, too, are always actual intelligences, and move the heavenly bodies as the object of love and desire moves the object loving it without itself being moved. The heavenly bodies move therefore because of a desire to perfect themselves, or to become like unto their movers.

So far Ibn Daud agrees with the philosophers, because the doctrines so far expounded are not incompatible with the Bible. But when the philosophers raise the question, How can the many originate from the One, the manifold universe from the one G.o.d, and attempt to answer it by their theory of successive emanations, Ibn Daud calls a halt. The human mind is not really so all-competent as to be able to answer all questions of the most difficult nature. The doctrine of successive emanations is that elaborated by Alfarabi and Avicenna, which we have already seen quoted and criticized by Judah Halevi (_cf._ above, p. 178 f.). It is slightly more complicated in Ibn Daud, who speaks of the treble nature of the emanations after the first Intelligence--an intelligence, a soul and a sphere--whereas in Halevi's account there were only two elements, the soul not being mentioned.[240]

We have so far dealt with the more theoretical part of theology and religion, so much of it as may be and is accepted by nations and religions other than Jews. It remains now to approach the more practical and the more specifically Jewish phases of religion; though in the purely ethical discussions and those relating to Providence we have once more a subject of general application, and not exclusively Jewish.

As the introduction to this second part of the subject, Abraham Ibn Daud devotes a few words to the theoretical defence of tradition, or rather of mediate knowledge. He does so by a.n.a.lyzing the various kinds of knowledge. Knowledge, he says, is either intelligible or sensible.

Sensible knowledge is either directly perceived by the subject or received by him from another who perceived it directly, and whom he believes or not as the case may be. That is why some things believed by some people are not believed by others. The ignorant may think that this weakness is inherent in matters received from others. As a matter of fact such indirect knowledge is at the basis of civilization and makes it possible. If every man were to judge only by what he sees with his own eyes, society could never get along; there would be no way of obtaining justice in court, for the judge would not put credence in witnesses, and the parties would have to fight out their differences, which would lead to bloodshed and the disruption of social life. The different att.i.tude of different persons to a given matter of belief is due not necessarily to the uncertainty of the thing itself, but to the manner in which the object of the belief came down to us. If a thing rests upon the testimony of one man, its warrant is not very strong. But if a whole nation witnessed an event, it is no longer doubtful, unless we suppose that the account itself is due to one writer, and the event never happened. We shall discuss these matters in the sequel.[241]

Having justified in a general way the knowledge derived from the testimony of others by showing that society could not exist without depending upon such knowledge; though admitting at the same time that caution should be exercised and criticism in determining what traditional testimony is valid or not, we now take up one of these traditional phenomena which plays perhaps the most important role in Jewish theology, namely, the phenomenon of prophecy. Before discussing the traditional aspect of this inst.i.tution and its purpose in the history of religion we must consider it from its natural and psychological aspect.

The explanation of Ibn Daud--it was not original with him, as we have already seen the non-religious philosopher in Halevi's Cusari giving utterance to the same idea, and in Jewish philosophy Israeli touches on it--the explanation of Ibn Daud is grounded in his psychology, the Aristotelian psychology of Avicenna. The first degree of prophecy, he says, is found in true dreams, which happen to many people. Just as waking is a state of the body in which it uses the external as well as the internal senses, so sleeping is a state of the body in which the soul suppresses the external senses by putting them to sleep, and exercises its "natural" powers only, such as the beating of the heart pulse, respiration, and so on. The internal senses are also at work during sleep, or at least some of them. In particular the power of imagination is active when the external senses are at rest. It then makes various combinations and separations and brings them to the common sense. The result is a dream, true or false. When the senses are weak for one reason or another this power becomes active and, when not controlled by the reason, produces a great many erroneous visions and ideas, as in the delusions of the sick.