The Library of Original Sources, Vol 4


Moses Maimonides

Arabian civilization added only two important ideas to philosophy, one the introduction of the Divine Will as the final cause of the universe by the Jew Avicebron, the other the combination of Jewish theology with the philosophy of Aristotle by the Jew Moses Maimonides.

Moses Maimonides was born at Cordova, 1135 A.D. The invasion of the Mohammedan fanatics from Africa in 1148 A. D. drove the family from Cordova, and eleven years later they are thought to have been compelled to embrace Islam at Fez, though this apostasy is much doubted. Moses spent a number of years in wandering, butfinally settled at Old Cairo, and the last thirty years of his life were lived there, first as jeweller, then doctor, and at last court physician. He died in 1204 A. D.

His great work was done in theology as a commentator on the Old Testament and the Talmud, and in philosophy by combining Jewish theology with the thought of Aristotle. His work is also a good example of the thought of the times. We give below his outline of his proof of God’s existence, his analogy between man and the universe, which Well illustrates the thought of the period, and his list of the propositions accepted from Aristotle, showing the foundations upon which the scholasticism of the time built.

Method for Proving God’s Existence

My proof of God’s existence, as far as I now can explain it in general terms, is as follows. The universe is either eternal or has had a beginning; if it had a beginning, there must necessarily exist a being which caused the beginning; this is clear to common sense; for a thing that has had a beginning, cannot be the cause of its own beginning, another being must have caused it.

The universe was, therefore, created by God. If on the other hand the universe were eternal, it could in various ways be proved that, apart from the things which constitute the universe, there exists a being which is neither body nor a force in a body, and which is one, eternal, not preceded by any cause, and immutable. That being is God. You see that the proofs for the Existence, the Unity and the Incorporeality of God must vary according to the propositions admitted by us. Only in this way we can succeed in obtaining a perfect proof, whether we assume the eternity or the creation of the universe. For this reason you will find in my works on the Talmud, whenever I have to speak of the fundamental principles of our religion, or to prove the existence of God, that I employ arguments which imply the eternity of the universe. I do not believe in that eternity, but I wish to establish the principle of the existence of God by an indisputable proof, and should not like to see this most important principle founded on a basis which every one could shake or attempt to demolish, and which others might consider as not being established at all; especially when I see that the proofs of the philosophers are based on those visible properties of things, which can only be ignored by personspossessing certain preconceived notions, while the Mutakallemim establish their arguments on propositions which are to such an extent contrary to the actual state of things as to compel these arguers to deny altogether the existence of the laws of nature. When I shall have to treat of the creation, I shall in a special chapter prove my opinion to some extent, and shall attain the same end which every one of the Mutakallemim had in view, yet I shall not contradict the laws of nature, or reject any such part of the Aristotelean theory as has been proved to be correct. Even the most cogent of the proofs offered by the Mutakallemim respecting the act of creation, has only been obtained by reversing the whole order of things and by rejecting everything fully demonstrated by the philosophers. I, however, shall be able to give a similar proof without ignoring the laws of nature and without being forced to contradict facts which have been clearly perceived. I find it necessary to mention to you the general propositions of the Mutakallemim, by which they prove the act of creation, the existence of God, His Unity and His Incorporeality. I intend to explain their method, and also to point out the inferences which are to be drawn from each proposition. After this, I shall describe those theories of the philosophers which are closely connected with our subject, and I shall then explain their method.

Do not ask me to prove in this work the propositions of the philosophers, which I shall briefly mention to you; they form the principal part of Physics and Metaphysics. Nor must you expect that I should repeat the arguments of the Mutakallemim in support of their propositions, with which they wasted their time, with which the time of future generations will likewise be wasted, and on which numerous books have been written. Their propositions, with few exceptions, are contradicted by the visible properties of things, and beset with numerous objections. For this reason they were obliged to write many books and controversial works in defence of their theories, for the refutation of objections, and for the reconciliation of all apparent contradictions, although in realty this object cannot be attained by any sophistical contrivance. As to the propositions of the philosophers which I shall briefly explain, and which are indispensable for the demonstration of the three principles—the Existence, the Unity, and the Incorporeality of God, they will for the greater part be admitted by you as soon as you shall hear them and understand their meaning; whilst in the discussion of other parts reference must be made for their proofs to works on Physics and Metaphysics, and if you direct yourattention to such passages as will be pointed out to you, you will find everything verified that requires verification.

I have already told you that nothing exists except God and this universe, and that there is no other evidence for His Existence but this universe in its entirety and in its several parts. Consequently the universe must be examined as it is; the propositions must be derived from those properties of the universe which are clearly perceived, and hence you must know its visible form and its nature. Then only will you find in the universe evidence for the existence of a being not included therein. I have considered it, therefore, necessary to discuss first in a merely colloquial manner, in the next chapter, the totality of existing things, and to confine our remarks to such as have been fully proved and established beyond all doubt. In subsequent chapters I shall treat of the propositions of the Mutakallemim, and describe the method by which they explain the four fundamental principles. In the chapters which will follow, I propose to expound the propositions of the philosophers and the methods applied by them in verifying those principles. In the last place, I shall explain to you the method applied by me in proving those four principles, as I have stated to you.

A Parallel Between the Universe and Man

Know that this Universe, in its entirely, is nothing else but one individual being; that is to say, the outermost heavenly sphere, together with all included therein, is as regards individuality beyond all question a single being like Said and Omar. The variety of its substances—I mean the substances of that sphere and all its component parts—is like the variety of the substances of a human being: just as, e.g., Said is one individual, consisting of various solid substances, such as flesh, bones, sinews, of various humours, and of various spiritual elements; in like manner this sphere in its totality is composed of the celestial orbs, the four elements and their combinations; there is no vacuum whatever therein, but the whole space is filled up with matter. Its centre is occupied by the earth, earth is surrounded by water, air encompasses the water, fire envelopes the air, and this again is enveloped by the fifth substance ’(quintessence)’. These substances form numerous spheres, one being enclosed within another so that no intermediate empty space, no vacuum, is left. One sphere surrounds andclosely joins the other. All the spheres revolve with constant uniformity, without acceleration or retardation; that is to say, each sphere retains its individual nature as regards its velocity and the peculiarity of its motion; it does not move at one time quicker, at another slower. Compared with each other, however, some of the spheres move with less, others with greater velocity. The outermost, all-encompassing sphere, revolves with the greatest speed; it completes its revolution in one day, and causes every thing to participate in its motion, just as every particle of a thing moves when the entire body is in motion; for all existing beings stand in the same relation to that sphere as a part of a thing stands to the whole. These spheres have not a common centre; the centres of some of them are identical with the centre of the Universe, while those of the rest are different from it. Some of the spheres have a motion independent of that of the whole Universe, constantly revolving from East to West, while other spheres move from West to East. The stars contained in those spheres are part of their respective orbits; they are fixed in them, and have no motion of their own, but participating in the motion of the sphere of which they are a part, they themselves appear to move. The entire substance of this revolving fifth element is unlike the substance of those bodies which consist of the other four elements, and are enclosed by the fifth element.

The number of these spheres encompassing the Universe cannot possibly be less than eighteen; it may even be larger; but this is a matter for further investigation. It also remains an open question whether there are spheres which, without moving round the centre of the Universe, have nevertheless a circular motion. Within that sphere which is the nearest to us, a substance is contained which is different from the substance of the fifth element; it first received four primary forms, and then became in those four forms, four kinds of matter: earth, water, air, fire. Each of the four elements occupies a certain position of its own assigned to it by nature; it is not found in another place, so long as no other but its own natural force acts upon it; it is a dead body; it has no life, no perception, no spontaneous motion, and remains at rest in its natural place. When moved from its place by some external force, it returns towards its natural place as soon as that force ceases to operate. For the elements have the property of moving back to their place in a straight line, but they have no properties which would cause them to remain where they are, or to move otherwise than in a straight line. The rectilinear motionsof these four elements when returning to their original place are of two kinds, either centrifugal, viz., the motion of the air and the fire; or centripetal, viz., the motion of the earth, and the water; and when the elements have reached their original place, they remain at rest.

The spherical bodies, on the other hand, have life, possess a soul by which they move spontaneously; they have no properties by which they could at any time come to a state of rest; in their perpetual rotations they are not subject to any change, except that of position. The question whether they are endowed with an intellect, enabling them to comprehend, cannot be solved without deep research. Through the constant revolution of the fifth element, with all contained therein, the four elements are forced to move and to change their respective positions, so that fire and air are driven into water, and again these three elements enter the depth of the earth. Thus are the elements mixed together; and when they return to their respective places, parts of the earth, in quitting their places, move together with the water, the air and the fire. In this whole process the elements act and react upon each other. The elements intermixed, are then combined, and form at first various kinds of vapours; afterwards the several kinds of minerals, every species of plants, and many species of living beings, according to the relative proportion of the constituent parts. All transient beings have their origin in the elements, into which again they resolve when their existence comes to an end. The elements themselves are subject to being transformed from one into another; for although one substance is common to all, substance without form is in reality impossible, just as the physical form of these transient beings cannot exist without substance. The formation and the dissolution of the elements, together with the things composed of them, and resolving into them, follow each other in rotation. The changes of the finite substance, in successively receiving one form after the other, may therefore be compared to the revolution of the sphere in space, when each part of the sphere periodically reappears in the same position.

As the human body consists both of principal organs and of other members which depend on them and cannot exist without the control of those organs, so does the universe consist both of principal parts, viz., the quintessence, which encompasses the four elements and of other parts which are subordinated and require a leader, viz., the four elements and the things composed of them.

Again, the principal part in the human body, namely the heart,is in constant motion, and is the source of every motion noticed in the body; it rules over the other members, and communicates to them through its own pulsations the force required for their functions. The outermost sphere by its motion rules in a similar way over all other parts of the universe, and supplies all things with their special properties. Every motion in the universe has thus its origin in the motion of that sphere; and the soul of every animated being derives its origin from the soul of that same sphere.

The forces which according to this explanation are communicated by the spheres to this sublunary world are four in number, viz., (a) the force which effects the mixture and the composition of the elements, and which undoubtedly suffices to form the minerals; (b) the force which supplies every growing thing with its vegetative functions; (c) the force which gives to each living being its vitality, and (d) the force which endows rational beings with intellect. All this is effected through the action of light and darkness, which are regulated by the position and the motion of the spheres round the earth.

When for one instant the beating of the heart is interrupted, man dies, and all his motions and powers come to an end. In a like manner would the whole universe perish, and everything therein cease to exist if the spheres were to come to a stand still.

The living being as such is one through the action of its heart, although some parts of the body are devoid of motion and sensation, as, e.g., the bones, the cartilage, and similar parts. The same is the case with the entire universe; although it includes many beings without motion and without life, it is a single living being through the motion of the sphere, which may be compared to the heart of an animated being. You must therefore consider the entire globe as one individual being which is endowed with life, motion, and a soul. This mode of considering the universe is, as will be explained, indispensable, that is to say, it is very useful for proving the unity of God; it also helps to elucidate the principle that He who is One has created only one being.

Again, it is impossible that any of the members of a human body should exist by themselves, not connected with the body, and at the same time should actually be organic parts of that body, that is to say, that the liver should exist by itself, the heart by itself, or the flesh by itself. In like manner, it is impossible that one part of the Universe should exist independently of the other parts in the existing order of things as here considered, viz., that the fire should exist without theco-existence of the earth, or the earth without the heaven, or the heaven without the earth.

In man there is a certain force which unites the members of the body, controls them, and gives to each of them what it requires for conservation of its condition, and for the repulsion of injury—the physicians distinctly call it the leading force in the body of the living being; sometimes they call it "nature." The Universe likewise possesses a force which unites the several parts with each other, protects the species from destruction, maintains the individuals of each species as long as possible, and endows some individual beings with permanent existence. Whether this force operates through the medium of the sphere or otherwise remains an open question.

Again, in the body of each individual there are parts which are intended for a certain purpose, as the organs of nutrition for the preservation of the individual, the organs of generation for the preservation of the species, the hands and eyes for administering to certain wants, as to food, etc.; there are also parts which, in themselves, are not intended for any purpose, but are mere accessories and adjuncts to the constitution of the other parts. The peculiar constitution of the organs, indispensable for the conservation of their particular forms and for the performance of their primary functions, produces, whilst it serves its special purpose, according to the nature of the substance, other things, such as the hair and the complexion of the body. Being mere accessories, they are not formed according to a fixed rule; some are altogether absent in many individuals; and vary considerably in others. This is not the case with the organs of the body. You never find that the liver of one person is ten times larger than that of another person, but you may find a person without a beard, or without hair on certain parts of his body, or with a beard ten times longer than that of another man. Instances of this phenomenon, v/z., great variation as regards hair and colour, are not rare. The same differences occur in the constitution of the Universe. Some species exist as an integral part of the whole system; these are constant and follow a fixed law; though they vary as far as their nature permits, this variation is insignificant in quantity and quality. Other species do not serve any purpose; they are the mere result of the general nature of transient things, as e.g., the various insects which are generated in dunghills, the animals generated in rotten fruit, or in fetid liquids, and worms generated in the intestines, etc. In short, everything devoid of the power of generation belongs to this class. You will,therefore, find that these things do not follow a fixed law, although their entire absence is just as impossible as the absence of different complexions and of different kinds of hair amongst human beings.

In man there are substances the individual existence of which is permanent, and there are other substances which are only constant in the species, not in the individuals, as, e.g., the four humours. The same is the case in the Universe; there are substances which are constant in individuals, such as the fifth element, which is constant in all its formations, and other substances which are constant in the species, as e.g., the four elements and all that is composed of them.

The same forces which operate in the birth and the temporal existence of the human being operate also in his destruction and death. This truth holds good with regard to this whole transient world. The causes of production are at the same time the causes of destruction. This may be illustrated by the following example. If the four forces which are present in every being sustained by food, viz., attraction, retention, disgestion, and secretion, were, like intelligent forces, able to confine themselves to what is necessary, and to act at the proper time and within the proper limits, man would be exempt from those great sufferings and the numerous diseases [to which he is exposed]. Since, however, such is not the case, and since the forces perform their natural functions without thought and intelligence, without any consciousness of their action, they necessarily cause dangerous maladies and great pains, although they are the direct causes of the birth and the temporal existence of the human being. This fact is to be explained as follows: if the attractive force would absorb nothing but that which is absolutely beneficial, and nothing but the quantity which is required, man would be free from many such sufferings and disorders. But such is not the case; the attractive force absorbs any humour that comes within the range of its action, although such humour be ill-adapted in quality or in quantity. It is, therefore, natural that sometimes a humour is absorbed which is too warm, too cold, too thick, or too thin, or that too much humour is absorbed, and thus the veins are choked, obstruction and decay ensue, the quality of the humour is deteriorated, its quantities altered, diseases are originated, such as scurvy, leprosy, abscess, or a dangerous illness, such as cancer, elephantiasis, gangrene, and at last the organ or organs are destroyed. The same is the case with every one of the four forces, and with all existing beings. The same force that originates all things,and causes them to exist for a certain time, namely, the combination of the elements which are moved and penetrated by the forces of the heavenly spheres, the same cause becomes throughout the world a source of calamaties, such as devastating rain, showers, snowstorms, hail, hurricane, thunder, lightning, malaria, or other terrible catastrophes by which a place or many places or an entire country may be laid waste, such as landslips, earthquakes, meteoric showers and floods issuing forth from the seas and from the interior of the earth.

Bear in mind, however, that in all that we have noticed about the similarity between the Universe and the human being, nothing would warrant us to assert that man is a microcosm; for although the comparison in all its parts applies to the. Universe and any living being in its normal State, we never heard that any ancient author called the ass or the horse a microcosm. This attribute has been given to man alone on account of his peculiar faculty of thinking, I mean the intellect, i.e., the hylic intellect which appertains to no other living being. This may be explained as follows. An animal does not require for its sustenance any plan, thought or scheme; each animal moves and acts by its nature, eats as much as it can find of suitable things, it makes its resting-place wherever it happens to be, cohabits with any mate it meets while in heat in the periods of its sexual excitement. In this manner each individual conserves itself for a certain time, and perpetuates the existence of its species without requiring for its maintenance the assistance or support of any of its fellow creatures; for all the things to which it has to attend it performs by itself. With man it is different; if an individual had asolitary existence, and were, like an animal, left without guidance, he would soon perish, he would not endure even one day, unless it were by mere chance, unless he happened to find something upon which he might feed. For the food which man requires for his subsistence demands much work and preparation, which can only be accomplished by reflection and by plan; many vessels must be used, and many individuals, each in his peculiar work, must be employed. It is therefore necessary that one person should organise the work and direct men in such a manner that they should properly cooperate, and that they should assist each other. The protection from heat in summer and from cold in winter, and shelter from rain, snow, and wind, require in the same manner the preparation of many things, none of which can properly be done without design and thought. For this reason man has been endowed with intellectual faculties, which enable him to think, consider, and act,and by various labours to prepare and procure for himself food, dwelling and clothing, and to control every organ of his body, causing both the principal and the secondary organs to perform their respective functions. Consequently, if a man, being deprived of his intellectual faculties, only possessed vitality, he would in a short time be lost. The intellect is the highest of all faculties of living creatures; it is very difficult to comprehend, and its true character cannot be understood as easily as man’s other faculties.

There also exists in the Universe a certain force which controls the whole, which sets in motion the chief and principal parts, and gives them the motive power for governing the rest. Without that force, the existence of this sphere, with its principal and secondary parts, would be impossible. It is the source of the existence of the Universe in all its parts. That force is God; blessed be His name! It is on account of this force that man is called microcosm; for he likewise possesses a certain principle which governs all the forces of the body, and on account of this comparison God is called "the life of the Universe" (Deut. xii. 7.)

You must understand that in the parallel which we have drawn between the whole universe, on the one hand, and the individual man, on the other, there is a complete harmony in all the points which are mentioned above; only in the following three points a discrepancy may be .noticed.

First, the principal organ of any living being which has a heart, derives a benefit from the organs under the control of the heart, and the benefits of the organs thus become the benefits of the heart. This is not the case in the constitution of the universe. That part which bestows authority or distributes power, does not receive in return any benefit from the things under its control; whatever it grants, is granted in the manner of a generous benefactor, not from any selfish motive, but from a natural generosity and kindliness; only for the sake of imitating the ways of the Most High.

Secondly, living creatures endowed with a heart have it within the body and in the midst thereof; there it is surrounded by organs which it governs. Thus it derives a benefit from them, for they guard and protect it, and they do not allow that any injury from without should approach it. The reverse occurs in the case of the Universe. The superior part encompasses the inferior parts, it being certain that it cannot be affected by the action of any other being; and even if it could be affected, there is nobody without it that could affect it. Whileit influences—all that it contained within, it is not influenced by any act or force of any material being. There is, however, some similarity [between the universe and man] in this point. In the body of animals, the organs more distant from the principal organ are of less importance than those nearer to it. Also in the universe, the nearer the parts are to the centre, the greater is their turbidness, their solidity, their inertness, their dimness and darkness, because they are further away from the loftiest element, from the source of light and brightness, which moves by itself and the substance of which is the most rarefied and simplest: from the outermost sphere. At the same ratio at which a body is near this sphere, it derives properties from it, and rises above the spheres behind it.

Thirdly. The faculty of thinking is a force inherent in the body, and is not separated from it, but God is not a force inherent in the body of the universe, but is separate from all its parts. How God rules the universe and provides for it is a complete mystery; man is unable to solve it. For, on the one hand, it can be proved that God is separate from the universe, and in no contact whatever with it; but, on the other hand, His rule and providence can be proved to exist in all parts of the universe, even in the smallest. Praised be He whose perfection is above our comprehension.

It is true, we might have compared the relation between God and the universe, to the relation between the absolute acquired intellect and man; it is not a power inherent in the body, but a power which is absolutely separate from the body, and is from without brought into contact with the body. The rational faculty of man may be further compared to the intelligence of the spheres, which are, as it were, material bodies. But the intelligences of the spheres, purely spiritual beings, as well as man’s absolute and acquired intellect, are subjects of deep study and research; the proof of their existence, though correct, is abstruse, and includes arguments which present doubts, are exposed to criticism, and can be easily attacked by objectors. We have, therefore, preferred to illustrate the relation of God to the universe by a simile which is clear, and which will not be contradicted in any of the points which have been laid down by us without any qualification. The opposition can only emanate either from an ignorant man, who contradicts truths even if they are perfectly obvious, just as a person unacquainted with geometry rejects elementary propositions which have been clearly demonstrated, or from the prejudiced man who deceives himself. Those, however, who wish to study the subject mustpersevere in their studies until they are convinced that all our observations are true, and until they understand that our account of this universe unquestionably agrees with the existing order of things. If a man is willing to accept this theory from one who understands how to prove things which can be proved, let him accept it, and let him establish on it his arguments and proofs. If, on the other hand, he refuses to accept without proof even the foregoing principles, let him enquire for himself, and untimately he will find that they are correct. "Lo this, we have searched it, so it is; hear it, and know thou it for thy good."

Propositions Admitted

Twenty-five of the propositions which are employed in the proof for the existence of God, or in the arguments demonstrating that God is neither corporeal nor a force connected with a material being, or that He is One, have been fully established, and their correctness is beyond doubt. Aristotle and the Peripatetics who followed him have proved each of these propositions. There is, however, one proposition which we do not accept—namely, the proposition which affirms the Eternity of the Universe, but we will admit it for the present, because by doing so we shall be enabled clearly to demonstrate our own theory.

Proposition I.

The existence of an infinite magnitude is impossible.

Proposition II.

The co-existence of an infinite number of finite magnitudes is impossible.

Proposition III.

The existence of an infinite number of causes and effects is impossible, even if these were not magnitudes; if e.g., one Intelligence were the cause of a second, the second the cause of a third, the third the cause of a fourth, and so on, the series could not be continued ad infinitum.

Proposition IV.

Four categories are subject to change:—
(a.) Substance.—Changes which affect the substance of a thing are called genesis and destruction.
(b.) Quantity.—Changes in reference to quantity are increase and decrease.
(c.) Quality.—Changes in the qualities of things are transformations.
(d.) Place.—Changes of place is called motion.

The term "motion" is properly applied to Change of place, but is also used in a general sense of all kinds of changes.

Proposition V.

Motion implies change and transition from potentiality to actuality.

Proposition VI.

The motion of a thing is either essential or accidental; or it is due to an external force, or to the participation of the thing in the motion of another thing. This latter kind of motion is similar to the accidental one. An instance of essential motion may be found in the translation of a thing from one place to another. The accident of a thing, as, e.g., its black colour, is said to move when the thing itself changes its place. The upward motion of a stone, owing to a force applied to it in that direction, is an instance of a motion due to an external force. The motion of a nail in a boat may serve to illustrate motion due to the participation of a thing in the motion of another thing; for when the boat moves, the nail is said to move likewise. The same is the case with everything composed of several parts: when the thing itself moves, every part of it is likewise said to move.

Proposition VII.

Things which are changeable are, at the same time, divisible. Hence everything that moves is divisible, and consequently corporeal, but that which is :indivisible cannot move, and cannot therefore be corporeal.

Proposition VIII.

A thing that moves accidentally must come to rest, because it does not move of its own accord; hence accidental motion cannot continue for ever.

Proposition IX.

A corporeal thing that sets another corporeal thing in motion can only effect this by setting itself in motion at the time it causes the other thing to move.

Proposition X.

A thing which is said to be contained in a corporeal object must satisfy either of the two following conditions: it either exists through that object, as is the case with accidents, or it is the cause of the existence of that object; such as, e.g., its essential property. In both casesit is a force existing in a corporeal object.

Proposition XI.

Among the things which exist through a material object, there are some which participate in the division of the object, and are therefore accidentally divisible, as, e.g., its colour, and all other qualities that spread throughout its parts. On the other hand, among the things which form the essential elements of an object, there are some which cannot be divided in any way, as, e.g., the soul and the intellect.

Proposition XII.

A force which occupies all parts of a corporeal object is finite, the object itself being finite.

Proposition XIII.

None of the several kinds of change can be continuous, except motion from place to place, provided it be circular.

Proposition XIV.

Locomotion is in the natural order of the several kinds of motion the first and foremost. For genesis and corruption are preceded by transformation, which, in its turn, is preceded by the approach of the transforming agent to the object which is to be transformed. Also, increase and decrease are impossible without previous genesis and corruption.

Proposition XV.

Time is an accident that is related and joined to motion in such a manner that the one is never found without the other. Motion is only possible in time, and the idea of time cannot be conceived otherwise than in connection with motion; things which do not move have no relation to time.

Proposition XVI.

Incorporeal bodies can only be numbered when they are forces situated in a body: the several forces must then be counted together with substances or objects in which they exist. Hence purely spiritual beings, which are neither corporeal nor forces situated in corporeal objects, cannot he counted, except when considered as causes and effects.

Proposition XVII.

When an object moves, there must be some agent that moves it, either without that object, as, e.g., in the case of a stone set in motion by the hand; or within, e.g., when the body of a living being moves. Living beings include in themselves, at the same time, the moving agent and the thing moved; when, therefore, a living being dies, and the moving agent, the soul, has left the body, i.e., the thing moved,the body remains for some time in the same condition as before, and yet cannot move in the manner it has moved previously. The moving agent, when included in the thing moved, is hidden from, and imperceptible to, the senses. This circumstance gave rise to the belief that the body of an animal moves without the aid of a moving agent. When we therefore affirm, concerning a thing in motion, that it is its own moving agent, or, as is generally said, that is moves of its own accord, we mean to say that the force which really sets the body in motion exists in that body itself.

Proposition XVIII.

Everything that passes over from a state of potentiality to that of actuality, is caused to do so by some external agent; because if that agent existed in the thing itself, and no obstacle prevented the transition, the thing would never be in a state of potentiality, but always in that of actuality. If, on the other hand, while the thing itself contained that agent, some obstacle existed, and at a certain time that obstacle was removed, the same cause which removed the obstacle would undoubtedly be described as the cause of the transition from potentiality to actuality, [and not the force situated within the body]. Note this.

Proposition XIX.

A thing which owes its existence to certain causes, has in itself merely the possibility of existence; for only if these causes exist, the thing likewise exists. It does not exist if the causes do not exist at all, or if they have ceased to exist, or if there has been a change in the relation which implies the existence of that thing as a necessary consequence of those causes.

Proposition XX.

A thing which has in itself the necessity of existence cannot have for its existence any cause whatever.

A thing composed of two elements has necessarily their composition as the cause of its present existence. Its existence is therefore not necessitated by its own essence; it depends on the existence of its two component parts and their combination.

Proposition XXII.

Material objects are always composed of two elements [at least], and are without exception subject to accidents. The two component elements of all bodies are substance and form. The accidents attributed to material objects are quantity, geometrical form, and position.

Proposition XXIII.

Everything that exists potentially, and whose essence includes a certain state of possibility, may at some time be without actual existence.

Proposition XXIV.

That which is potentially a certain thing is necessarily material for the state of possibility is always connected with matter.

Proposition XXV.

Each compound substance consists of matter and form, and requires an agent for its existence, viz., a force which sets the substance in motion, and thereby enables it to receive a certain form. The force which thus prepares the substance of a certain individual being, is called the immediate motor.

Here the necessity arises of investigating into properties of motion, the moving agent and the thing moved. But this has already been explained sufficiently; and the opinion of Aristotle may be expressed in the following proposition: Matter does not move of its own accord—an important proposition that led to the investigation of the Prime Motor (the first moving agent).

Of these foregoing twenty-five propositions some may be verified by means of a little reflection and the application of a few propositions capable of proof, or of axioms or theorems of almost the same force, such as have been explained by me. Others require many arguments and propositions, all of which, however, have been established by conclusive proofs partly in the Physics and its commentaries, and partly in the Metaphysics and its commentary. I have already stated that in this work it is not my intention to copy the books of the philosophers which are closely connected with our subject, and which we want for our purpose.

To the above propositions one must be added which enunciates that the universe is eternal, and which is held by Aristotle to be true, and even more acceptable than any other theory. For the present we admit it, as a hypothesis, only for the purpose of demonstrating our theory. It is the following proposition:

Proposition XXVI.

Time and motion are eternal, constant, and in actual existence.

In accordance with this proposition, Aristotle is compelled to assume that there exists actually a body with constant motion, viz., the fifth element. He therefore says that the heavens are not subject to genesis or destruction, because motion cannot be generated nor destroyed. He also holds that every motion must necessarily bepreceded by another motion, either of the same or of a different kind. The belief that the locomotion of an animal is not preceded by another motion, is not true; for the animal is caused to move, after it had been in rest, by the intention to obtain those very things which bring about that locomotion. A change in its state of health, or some image, or some new idea can produce a desire to seek that which is conducive to its welfare and to avoid that which is contrary. Each of these three causes sets the living being in motion, and each of them is produced by various kinds of motion. Aristotle likewise asserts that everything which is created, must, before its actual creation, have existed in potentia. By inferences drawn from this assertion he seeks to establish his proposition, viz., The thing that moves is finite, and its path finite; but it repeats the motion in its path an infinite number of times. This can only take place when the motion is circular, as has been of an infinite number of things which do not co-exist but follow one after the other.

Aristotle frequently attempts to establish this proposition; but I believe that he did not consider his proofs to be conclusive. It appeared to him to be the most probable and a likely proposition. His followers, however, and the commentators of his books, contend that it contains not only a probable but a demonstrative proof, and that it has, in fact, been fully established. On the other hand, the Mutakallemim try to prove that the proposition cannot be true, as, according to their opinion, it is impossible to conceive how an infinite number of things could even come into existence successively. They assume this impossibility as an axiom. I, however, think that this proposition is admissible, but neither demonstrative, as the commentators of Aristotle assert, nor, on the other hand, impossible, as the Mutakallemim say. We have no intention to explain here the proofs given by Aristotle, or to show our doubts concerning them, or to set forth our opinion on the Creation of the universe. I here simply desire to mention those propositions which we shall require for the proof of the three principles stated above. Having thus quoted and admitted these propositions, I will now proceed to explain what may be inferred from them.



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Chicago: "Moses Maimonides," The Library of Original Sources, Vol 4 in The Library of Original Sources, ed. Oliver J. Thatcher (Milwaukee, Wisconsin: University Research Extension Co., 1907), 282–295. Original Sources, accessed February 25, 2024,

MLA: . "Moses Maimonides." The Library of Original Sources, Vol 4, in The Library of Original Sources, edited by Oliver J. Thatcher, Milwaukee, Wisconsin, University Research Extension Co., 1907, pp. 282–295. Original Sources. 25 Feb. 2024.

Harvard: , 'Moses Maimonides' in The Library of Original Sources, Vol 4. cited in 1907, The Library of Original Sources, ed. , University Research Extension Co., Milwaukee, Wisconsin, pp.282–295. Original Sources, retrieved 25 February 2024, from