In the name of the Lord, God of the World1

[INTRODUCTION TO THE SECOND PART]

The premises² needed for establishing the existence of the deity, may He be exalted, and for the demonstration that He is neither a body nor a force in a body and that He, may His name be sublime, is one, are twenty-five — all of which are demonstrated without there being a doubt as to any point concerning them. For Aristotle and the Peripatetics after him have come forward with a demonstration for every one of them. There is one premise that we will grant them, for through it the objects of our quest will be demonstrated, as I shall make clear; this premise is the eternity of the world.

1] The first premise: The existence of any infinite magnitude is impossible.

2] The second premise: The existence of magnitudes of which the number is infinite is impossible — that is, if they exist together.³

3] The third premise: The existence of causes and effects of which the number is infinite is impossible, even if they are not endowed with magnitude. For instance, the assumption that one particular intellect, for example, has as its cause a second intellect, and that the cause of this second intellect is a third one, and that of the third a fourth, and so on to infinity, [2b] is likewise clearly impossible.

4] The fourth premise: Change exists in four categories: it exists in the category of substance, the changes occurring in a substance being generation and corruption. It exists in the category of quantity, namely, as growth and decrease. It exists in the category of quality, namely, as alteration. It exists in the category of place, namely, as the motion of translation. It is this change in the category of place that is more especially called motion.

5] The fifth premise: Every motion is a change and transition from potentiality to actuality.

6] The sixth premise: Of motions, some are essential and some accidental, some are violent and some are motions of a part — this being a species of accidental motion. Now essential motion is, for example, the translation of a body from one place to another. Accidental motion is, for example, when a blackness existing in this particular body is said to be translated from one place to another. Violent motion is, for example, the motion of a stone upwards through the action of something constraining it to that. Motion of a part is, for example, the motion of a nail in a ship; for when the ship is in motion, we say that the nail is likewise in motion. Similarly when any compound is in motion as a whole, its parts are likewise said to be in motion.

7] The seventh premise: Everything changeable is divisible. Hence everything movable is divisible and is necessarily a body. But everything that is indivisible is not movable; hence it will not be a body at all.

8] The eighth premise: Everything that is moved owing to accident must of necessity come to rest, inasmuch as its motion is not in virtue of its essence. Hence it cannnot be moved forever in that accidental motion.

9] [3a] The ninth premise: Every body that moves another body moves the latter only through being itself in motion when moving the other body.

10] The tenth premise: Everything that is said to be in a body is divided into two classes: either it subsists through the body, as do the accidents, or the body subsists through it, as in the case of the natural form. Both classes are to be considered as a force in the body.

11] The eleventh premise: Some of the things that subsist through body are sometimes divided through the division of the body and hence are divisible according to accident, as for instance the colors and the other forces that are distributed through the whole of the body. In a like manner some of the things that constitute a body are not divisible in any way, as for instance the soul and the intellect.

12] The twelfth premise: Every force that is found distributed through a body is finite because the body is finite.

13] The thirteenth premise: It is impossible that one of the species of motion be continuous, except local motion, and of this only that which is circular.

14] The fourteenth premise: Local motion is the primary and the first by nature among all motions; for generation and corruption are preceded by alteration, and alteration is preceded by the approach of that which alters to that which is to be altered; and there is no growth and diminution except when they are preceded by generation and corruption.

15] The fifteenth premise: Time is an accident consequent upon motion and is necessarily attached to it. Neither of them exists without the other. Motion does not exist except in time, and time cannot be conceived by the intellect except together with motion. And all that with regard to which no motion can be found, does not fall under time.

16] The sixteenth premise: In whatsoever is not a body, [3b] multiplicity cannot be cognized by the intellect, unless the thing in question is a force in a body, for then the multiplicity of the individual forces would subsist in virtue of the multiplicity of the matters or substances in which these forces are to be found.4 Hence no multiplicity at all can be cognized by the intellect in the separate things, which are neither a body nor a force in a body, except when they are causes and effects.

17] The seventeenth premise: Everything that is in motion has of necessity a mover; and the mover either may be outside the moved object, as in the case of a stone moved by a hand, or the mover may be in the body in motion, as in the case of the body of a living being, for the latter is composed of a mover and of that which is moved. It is for this reason that when a living being dies and the mover — namely, the soul —is lacking from it, that which is moved — namely, the organic body — remains at the moment in its former state, except that it is not moved with that motion. However, inasmuch as the mover that exists in that which is moved is hidden and does not appear to the senses, it is thought of living beings that they are in motion without having a mover. Everything moved that has a mover within itself is said to be moved by itself—the meaning being that the force moving that which, in the object moved, is moving according to essence, exists in the whole of that object.

18] The eighteenth premise: Everything that passes from potentiality to actuality has something other than itself that causes it to pass, and this cause is of necessity outside that thing. For if that cause were that thing and there were no obstacle to prevent this passage, the thing would not have been for a certain time in potentia but would have always been in actu. If, however, the cause of the passage from potentiality to actuality subsisted in the thing, and if there was at the same time an obstacle to it, which was subsequently removed, there is no doubt that the factor that put an end to the obstacle is the one that caused that potentiality to pass into actuality. Understand this.

19] The nineteenth premise: Everything that has a cause for its existence is only possible with regard to existence in respect to its own essence. For it exists if its causes are present. If, however, they are not present, or if they become nonexistent, or if their relation [4a] that entails the existence of the thing in question has changed, that thing does not exist.

20] The twentieth premise: Everything that is necessarily existent in respect to its own essence has no cause for its existence in any way whatever or under any condition.

21] The twenty-first premise: Everything that is composed of two notions has necessarily that composition as the cause of its existence as it really is, and consequently is not necessarily existent in respect to its own essence, for it exists in virtue of the existence of its two parts and of their composition.

22] The twenty-second premise: Every body is necessarily composed of two things and is necessarily accompanied by accidents. The two things constituting it are its matter and its form; and the accidents accompanying it are quantity, shape, and position.

23] The twenty-third premise: It is possible for whatsoever is in potentia and in whose essence there is a certain possibility, not to exist in actu at a certain time.

24] The twenty-fourth premise: Whatsoever is something in potentia is necessarily endowed with matter, for possibility is always in matter.

25] The twenty-fifth premise: The principles of an individual compound substance are matter and form. And there is no doubt about the necessity of there being an agent, I mean to say a mover that moves the substratum so as to predispose it to receive the form. That is the proximate mover, which predisposes the matter of a certain individual. At this point it is necessary to engage in speculation with regard to motion, the mover, and the moved. However, with regard to all this, everything that it was necessary to explain has already been explained. The text of the words of Aristotle is: Matter does not move itself.5 This therefore is the capital premise calling for an inquiry concerning the existence of the Prime Mover. [4b]

Of the twenty-five premises that I have put before you in the form of a preface, some become manifest with very little reflection and are demonstrative premises and first intelligibles or notions approaching the latter, as may be seen in the epitome we have made of their orderly exposition. Others require a number of demonstrations and premises leading up to them. However, all of them have been given demonstrations as to which no doubt is possible. With regard to some of them, this has been done in the Book of “Akroasis”⁶ and its commentaries; with regard to others, in the Book of “Metaphysics” and its commentary. I have already made it known to you that the purpose of this Treatise is not to transcribe the books of the philosophers and to explain the most remote of the premises, but to mention the proximate premises that are required for our purpose.

I shall add to the premises mentioned before, one further premise that affirms as necessary the eternity of the world. Aristotle deemed it to be correct and the most fitting to be believed. We shall grant him this premise by way of a hypothesis⁷ in order that the clarification of that which we intended to make clear should be achieved. This premise, which among them is the twenty-sixth, [consists in Aristotle’s statement] that time and movement are eternal, perpetual, existing in actu.8 Hence it follows of necessity, in his opinion, that there is a body, moving with an eternal movement, existing in actu; and this is the fifth body. For this reason, he says that the heaven is not subject to generation and corruption. For according to him, movement is not subject to generation and corruption; for he says that every movement is necessarily preceded by another movement either of the same species as itself or of other species, and that what is thought with regard to living beings — namely, that their local movement is not preceded at all by another movement — is not correct. For the cause of their movement after rest goes back finally to things calling for this local movement; these things being either an alteration [5a] of temperament necessitating a desire to seek what agrees with the living being or to flee from what disagrees with it, or an imagination, or an opinion occurring to it. Accordingly, any one of these three factors sets the living being in motion, and every one of them is necessitated by other movements. Similarly he says that in the case of everything that comes about in time, the possibility of its coming-about precedes in time its coming-about. From this there follow necessarily several points liable to validate his premise.⁹ According to this premise, a finite moving object moves upon a finite distance an infinite number of times, going back over the same distance in a circle. Now this is impossible except in circular movement, as is demonstrated in the thirteenth of these premises. According to this premise, that which is infinite must necessarily exist as a succession and not simultaneously.¹⁰

This is the premise that Aristotle constantly wishes to establish as true. Now to me it seems that he does not affirm categorically that the arguments he puts forward in its favor constitute a demonstration. The premise in question¹¹ is rather, in his opinion, the most fitting and the most probable. However, his followers and the commentators of his books claim that the premise is necessary and not merely possible and that it has already been demonstrated. On the other hand, every Mutakallim desires to establish that it is impossible. They say that there can be no mental representation of the coming-about in succession of an infinite number of things occurring in time. The strength of their argument is that it constitutes, in their opinion, a first intelligible. But to me it seems that the premise in question is possible — that is, neither necessary, as is affirmed by the commentators of the writings of Aristotle, nor impossible, as is claimed by the Mutakallimūn. It is not the purpose now to explain the arguments of Aristotle, or to raise our doubts concerning him, or to explain my opinion concerning the creation of the world in time. But the purpose at this point is to circumscribe the premises that we need for our [5b] three problems; after first having set forth these premises and having agreed to take-them as granted, I shall set out explaining what necessarily follows from them.