Alhassanain(p) Network for Heritage and Islamic Thought

Lesson Fifty-Five: Motion

The Concept of Motion

During the previous discussions the concept of motion became clear, and a simple definition of it was obtained: gradual change. Other definitions of motion have been given, some of which were mentioned in the course of the preceding discussions, including ‘the gradual emergence of a thing from potentiality to actuality,’ and another definition ascribed to Aristotle, that is, ‘the first perfection of a potential existentqua potential,’ which was mentioned in Lesson Forty and which means that an existent which possesses the potentiality and capacity for a perfection but lacks it at present, will advance toward it under certain conditions, and this advancing is preparatory to the achievement of the sought perfection. And the phrase ‘qua potential’ is added in order to exclude the specific form of the moving existent, because every potential existent has a specific form anyway, which may be considered its first perfection, but this first perfection is with respect to its actuality rather than its potentiality, and is irrelevant to motion.

The perfection of motion for a body pertains to its potentiality, and its being ‘first’ pertains to its priority for attaining its end. However, the first definition is to be preferred because it is more concise and conceptually clear, although none of them may be considered what in logical terminology is called a ‘complete definition’ (ḥadd-e tāmm ), because a complete definition is specific to whatnesses, which possess a genus and difference, while the concept of motion is a secondary philosophical intelligible abstracted from the manner of the moving existent, and in the external world there is no substance nor accident called motion; rather motion is the being gradual of the existence of a substance or accident and its flowing through the extension of time. Even according to Shaykh al-Ishrāq, who considered motion to be of the category of accidents, a complete definition cannot be given for it, because its category is a highest genus and does not possess genus and difference.

Another point we should mention is that instantaneous changes are abstracted from two existences, or at the least from the existence and nonexistence of a single thing, while motion is abstracted from a single existent and its extension through time. Numerical difference between something which changes and that into which it changes pertains only to its potential parts which continually become existent and nonexistent, although none of them has actual existence. In other words, motion is not a collection of existents which come into existence one after the other, rather it is abstracted from the extension of a single existent and it is infinitely divisible, although the division of it in the external world involves the appearance of rest and the destruction of its unity.

The Existence of Motion

In Lesson Fifty-One it was mentioned that a group of ancient Greek philosophers, such as Parmenides and Zeno of Elea denied that there was gradual change or motion. This position seems strange at first, and the question immediately arises in the mind of the reader or hearer as to whether they did not observe all these various motions?! Did they not themselves

move around?! But by examining their words more carefully it becomes clear that the matter is not quite so simple. Even the positions of some of those who believe in motion and stubbornly defend it (such as some Marxists) originate with the Eleatics!

The secret of the matter is that they considered the changes called motion to be a collection of successive instantaneous changes. For example, the motion of a body from one point to another was considered to be the successive resting of the body at the points between the two assumed points. In other words, they did not accept motion as something gradual and continuous, but rather as a collection of successive rests. Therefore, if someone else holds that motion has actual parts, in reality he has joined the ranks of those who deny motion.

The truth is that the existence of motion as a single gradual thing is undeniable. Even some instances of it, such as the gradual changes of psychic qualities, can be perceived by infallible presentational knowledge. The source of the error of the Eleatics are doubts that run counter to consciousness and self-evidence, and no uncertainty remains once these doubts are dispelled.

Problems Raised by those who Deny the Existence of Motion and their Solution

Those who have denied the existence of motion in the external world and who have considered it to be a mental concept which refers to a succession of rests have resorted to dubious notions the most important of which are the following two:

1. If motion exists as a single continuous thing in the external world, it must be considered as having parts, and since each of its parts possesses extension, each of these in turn will be divisible into other parts, and this division will continue infinitely. This implies that finite motion must be infinite.

Aristotle responded to this difficulty by claiming that motion does not have actual parts which could be finite or infinite, but rather that it can be divided into two parts, for example, in which case there will be two motions, not a single motion. Likewise, each part may be divided into two or more parts, and with each division performed in the external world a number of actual existents will come about. These divisions may be continued without end, and hence the supposed motion itself will be finite, although its potential parts will be infinite. No contradiction exists between these two propositions, because one of the conditions for a contradiction is the unity of the actual and the potential which does not obtain in this case, for being finite is the attribute of the motion as a whole, while being infinite is the attribute of its potential parts.

But it is better to ask one who reasons in this way what do you mean by finite motion being infinite? If what is meant by being infinite is the number of its parts, this number does not actually exist in any motion, and the appearance of any number, whether finite or infinite, in motion is due to its objective division, in which case a single motion will not exist. Likewise, everything which is divisible into two halves is presently a unit, but

whenever it is divided, it becomes two units, but this divisibility does not imply that it is both one and two!

If what is meant is that the infinite divisibility of motion implies that the continuous amount and quantity (rather than number) is finite from one side and infinite from another, because every part of its infinite parts will have a quantity, and the collection of these amounts will be infinite, the answer to this is that even if every extension is divisible into an infinite number of parts, the amount of any extension will still be a fraction of the amount of the whole. Hence, the sum of the quantities of the infinite fractions of motion will be the finite amount of the motion itself: (1/¥ ´ ¥=1).

It must be mentioned that this problem is not specific to motion, but covers all extensions, such as line and time. For this reason, those who raise these doubts consider every limited line to be composed of a limited number of extensionless points, and every limited portion of time to be composed of a determinate number of instants. They believe that although the points are not extended, a collection of several points could bring a line into existence: though an instant has no length or extension, a set of several of them brings about a portion of time; likewise, a collection of rests brings about motion; in reality, that which has objective existence are points, instants and rests. Line, time and motion are concepts abstracted from their collections.

In other words, they believe in ‘indivisible parts’ (juz’ lā yatajazzā ), that is, every extension is capable of being divided into limited parts, and they believe that the last division leads to parts which are no longer divisible. This is a problem about which philosophers have spoken much, and they have given numerous reasons for the invalidity of the notion of ‘indivisible parts,’ but this is not the place to review them.

2. The other problem is that when a body moves from point A towards point C, for example, at the first instant it is at point A, and at the third instant it is at point C, so, there is no other alternative but that at the second instant it must pass some point B which is between the other two, otherwise there could be no motion. Now, if it is assumed that the above-mentioned body is at point B at the second instant, this would imply that its motion is a collection of three rests, for rest is nothing but the residence of a body in a place, and if it did not reside there this would imply that there was no motion, for motion without passing the second point is impossible. Therefore, motion implies a contradiction (being and not being at an intermediate point).

The answer is that in this example three corresponding extensions are assumed: time, space and motion. If we consider three extended parts for each of them, it can be said that in the first part of time, the moving body has been in the first part of the space and that the first part of its motion corresponds to them, and likewise for the second and third parts. However, the occurrence of every part of the motion in the corresponding parts of time and space does not mean that the body is ever at rest. However, if we take points and moments in their real meaning, as lacking extension, it would have to be said that actual instants and points do not exist in time and space, and the assumption of an actual point in a line means its division into two line segments, such that the said point is the end of one segment and the

beginning of another. It is the same for the assumption of an instant in time and the assumption of a rest in motion. What it means for a body to be at a certain instant at a point in space is that if the extensions of time, space and motion were cut, their points of division would correspond to each other. This does not imply the existence of rest in the midst of motion, just as it does not imply the existence of points in a line or the existence of instants in time.

In reality, the source of this problem is that, on the one hand, being is considered to be equivalent to fixation, rest and residence, while on the other hand, time is assumed to be composed of instants and line composed of points. They attempted to present the extension of motion as a composition of atoms of rest by means of a comparison to the extensions of time and space, while being includes both fixed and flowing beings. Moments and points are ends of extensions of time and line, and are not considered to be parts of them. Likewise, rest appears as the stopping of motion, not as something that exists in the midst of a single motion so as to be considered a part of it.

Lesson Fifty-Six: Properties of Motion

The Constituent Factors of Motion

Noting that which has already been discussed regarding motion, it becomes clear that the occurrence of motion hinges on three things which may be called the constituents of motion:

1. The unity of the source of abstraction of motion. Contrary to other types of change, motion is abstracted from a single existent. Hence, every motion is a single entity in which no actual parts are to be found.

2. The fluidity and extension of motion in the expanse of time. Since that which is gradual does not occur without a correspondence to time, motion is not abstracted from instantaneous things and fixed existents, which are outside the realm of time, and it is not attributed to them.

3. Infinite divisibility. Just as every extension is infinitely divisible, so too is motion. Each potential part of motion is the changing predecessor (mutaghayyir ) in relation to the potential part which follows it, and the part which follows, with respect to the part which precedes it, is its changed successor (mutaghayyirun ilayh ).

The Features of Motion

In addition to the three things mentioned above, which are grasped through meditation on the essence of motion, and which are necessary for all motions, there are other things which may be called the features of motion. Noting the differences among them, specific kinds of motion may be considered, the most important of which are the following:

1.The channel of motion. It is possible for an existent to have numerous aspects of capacity for change. For example, it is possible for an apple to fall from a tree with a spatial or translative motion, and likewise it is possible for it to rotate or to gradually change color. However, each of these motions has its own specific ‘channel’ (bastar ) which distinguishes it from other motions. For example, the channel for the motion of the apple toward the ground is space, and this motion is spatial or one of displacement, or motion in the category of where (‘ayn ). The channel for the gradual change in its hue is color, and this is considered to be a change in the category of quality. The channel for its rotation is position, and it is taken to be a change in the category of position.

2.The course of motion. It is possible for something to move in various ways through a single channel. For example, the spatial movement or displacement of a star is possible in either a circular or an elliptical shape, or the motion of a ball from one point to another may be in a straight or a curved line. In this way another concept may be obtained which is more specific than the previous one, and this may be called the course (madār ; literally, orbit, here used in the sense of the course of motion) of motion. However, it must be noted that the expressionmadār has a broader meaning here than its literal meaning, the place of circling, just as the expression ‘curve’ has a broader meaning in mathematics than in ordinary usage, and it is possible for the curve which shows the course of a given change to be a straight line.

3.The direction of motion. It is also possible for motion in a single course to take place in various ways. For example, the motion of a top rotating on its axis may be from left to right or from right to left. Therefore, another feature must be considered for motion, and this is called the direction of motion.

4.The speed of motion. Speed is a concept which is obtained from the relation between the time and displacement of motion. For example, it is possible for a body to travel a certain distance in one minute or in two minutes. The distinguishing aspect between these two motions is speed.

5.Acceleration . It is possible for the speed of motion to gradually increase or decrease, as it is possible for the speed to remain constant. In the first case, the motion is becoming faster, or possesses a positive acceleration. In the second case it is becoming slower or possesses a negative acceleration, while in the third case it is said to be constant, or without acceleration, or as possessing zero acceleration.

6.The agent of motion. Among the things which differentiate types of motion is difference in the type of agent of motion. For example, there is a difference in kind between motions which have voluntary agents and those with natural agents, although there may be no difference externally. Likewise, multiple individual agents cause multiple individual motions, just as the multiple forces which successively come about by the two engines of an airplane causes the multiplicity of its motions, even if the two above mentioned motions are contiguous and without any temporal gap, and from a superficial point of view there seems to be but a single motion.

The Requirements of Motion

Philosophers have considered six things to be requirements of motion: origin (mabdā’ ), end (muntahā ), time, distance, subject (mutaḥarrak ) and agent (muharrik ).

1 & 2.Origin and end. Some of the definitions of motion suffice to warrant the requirement of an origin and end for every motion. For example, ‘the gradual emergence of actuality from potentiality’ implies that at the beginning a potentiality should exist and at the end of the motion an actuality. Hence, potentiality and actuality may be considered the origin and end of motion.

It appears that motion does not essentially require a relation to an origin or end, and hence, the assumption of infinite motion without beginning or end is not an irrational one. Accordingly, some ancient philosophers considered the motions of the celestial spheres to be without beginning or end in time, and so they had to take quite some pains to associate some origin and end with them. It may be said that origin or end are specific to limited motions, and that origin or end are implied by their limits, not implied by the motion itself, as every limited extension has an origin or end. Perhaps the source of the plausibility of considering motion to have an origin or end is that a means is thereby sought to determine the direction of motion.

Anyway, origin or end cannot be considered requirements of all motions.

It is necessary to mention that those who consider motion to require an origin or end do not take them to be within the motion itself, because every

part of motion is extended, and no matter how small a part is imagined, it will be divisible, and again it will have to have a beginning part. If a part of motion is called the origin or end of motion, this will be a relative attribution to the motion itself.

Taking potentiality and actuality as the origin and end of motion involves a certain laxity, for the terms origin and end are abstracted from the limits of motion, like point for line and moment for time, and they are considered to have an aspect of non-being. This is contrary to potentiality and actuality (especially the latter) which cannot be considered cases in which there are aspects of non-being.

Furthermore, the requirement of potentiality and actuality has not been established for motion, and it may be said that in order to abstract the concept of motion it is not necessary to take into account anything more than the gradual existence of a substance or accident. Therefore, another distinctive aspect of the first definition of motion (gradual change) is established.

3.Time . It was previously indicated that it is impossible for a thing to be gradual without a correspondence to time. For this reason, the corresponding extension in time was considered to be one of the fundamentals of motion. Since time and motion are analytic accidents of fluid existence, they may be considered to be two sides of the same coin.

4.Distance . By the ‘distance’ of motion philosophers mean a category to which the motion is related, such as the relation of rotation to the category of position, and the relation of translative motion to the category of space.

Distance is like a canal through which a moving thing flows. If it is assumed that the extension of motion is cut, and it comes to rest, then it may be said that the mentioned body is in the canal. Therefore, distance corresponds to the channel of motion. However, a subtle distinction may be drawn between distance and the channel of motion, namely, that the channel of motion is also applied to the specific whatness, such that every supposed part of motion can be considered to be an individual of that species. However, distance is commonly used as a term for the highest genus or category, and it is like an extended canal which embraces partial canals.

To explain further, motion as we know it is obtained from the extension of the existence of a substance or accident through the expanse of time, and it is possible that the existent which is the source of the abstraction of motion is perfected through the process of motion, such that from a part of it a specific whatness is abstracted, and from another part, another whatness. For example, if it is assumed that the color of an apple gradually changes from green to red, from a part of this motion the accidental whatness of green will be abstracted, while from another part the accidental whatness of red is abstracted, both of which are considered kinds of color. Color in turn is considered a sensory quality, and sensory quality belongs to the category of ‘quality.’ The distance of this motion is the very category of quality. But the channel of the motion is also applied in the case of the transformation of an individual of one specific quality to another individual. For example, the motion of a body from one place to another does not require the occurrence of kinds within the category of place, rather, one individual is constantly

transformed into another individual, regardless of the laxity in the use of ‘individual’ for the potential parts of motion, and likewise the laxity in the use of ‘category’ for the abstracted concept of place.

In any case, observing that changes from one kind to another in the process of motion are not permissible, philosophers considered categories to be channels of a general sort for motion, for motion never violates the limits of the categories, and they called the channels ‘distance.’

It should not be left unsaid that some philosophers considered specific difference between potential parts of motion to be not only permissible but necessary. However, it seems that specific difference can only be taken to obtain at the beginning or end of motion, because the abstraction of several whatnesses from the potential parts of motion implies the ability to consider a definite boundary for each of them. This indicates that the given motion is really a composite of several motions, however much it may seem superficially to be a single motion. For example, although the transformation of the color of an apple from green to yellow and from yellow to red seems to be a single process, if these colors and perhaps other colors which are intermediaries between them were different in kind, certain cut-off points in the motion would be abstracted, and the assumption of numerous cut-off points is like the assumption of the appearance of points in a line and implies numerous cuts even if no temporal separation between the cut-off points is assumed.

5.Subject : Another thing philosophers have considered to be necessary for motion is the subject of motion or the object moved (mutaḥarrik ). However, it must be noted that the expression ‘subject’ (mawḍū‘ ) is employed in the intellectual sciences in various senses, the most well known of which are indicated by the logical term, which is usually contrasted with ‘predicate,’ and the philosophical term, which is used in the case of substance insofar as it is the locus of accidents.

The first term is a secondary logical intelligible, and is applied to the first part of every predicative proposition, and even the concept of ‘contradiction’ in the proposition ‘contradictions are impossible’ is the subject of the proposition. It is clear that ‘subject’ in this sense is not relevant to the present discussion.

The second term is specific to the subjects of accidents, and if motion is also an objective accident, as was imagined by Shaykh Ishrāq, it will be in need of a subject. However, we have come to know that motion is not a kind of objective accident, but a kind of analytic accident of flowing existence. Hence, the establishment of a subject for all motions will only be correct in a third sense, which includes the source of the abstraction of analytical accidents. According to a famous expression in philosophy, a subject is only needed in the case of accidental motion in the respect in which it is an accident and not in the respect in which it possesses motion.

6.The Agent or Mover: The sixth thing which philosophers have considered to be necessary for motion is a mover or agent of motion. However, it must be borne in mind that the agent, meaning the generative cause (‘illat-e hastī bakhsh, literally, ‘existence granting cause’) is not specific to motion. Every existent which is an effect needs a generative

cause. Basically, motion has no entified specific referent beyond the existence of the substance or accident abstracted from it, and it is the existence of the substance or accident which requires a generative cause. The concept of motion is abstracted from the manner of its existence, and ‘composite making’ (ja‘l ta’līfī ) does not apply to it. In other words, the creation of a flowing substance or accident is the very creation of substantial or accidental motion. However, a natural agent, which is not a producer or creator, and is considered in another sense to be a preparatory cause, is specific to material phenomena all of which possess a kind of change, alteration or motion. But such an agent can only be assumed in the case of accidental motions, and in the appropriate place it will be explained that substantial motion does not need this sort of agent.

Lesson Fifty-Seven: Divisions of Motion

Introduction

We have learned that the constituents of motion exist in all motions and are invariable, and there is no difference on the basis of which different types of motion may be conceived. However, the characteristics and implications of motion are more or less different, and on the basis of these various kinds of motion can be differentiated. For example, differences in the course of transfer are completely sensible and the different forms for it which may be imagined cause differences in the related motions. But, on the one hand, the differences in courses are not limited to a certain number of types, and on the other hand, no specific philosophical conclusions are to be obtained on the basis of such differences. Hence, a categorization of motions on the basis of differences in their courses will not be of much benefit.

Likewise, the directions of motion, even if they are generally divided into six main well known directions [will not provide for a useful categorization]. First, this division is conventional; second, the division of motion on the basis of these differences yields no philosophical fruit. Also the speeds of motion are innumerable, but these differences are inconsequential for philosophical analysis.

The division of motion on the basis of differences among its agents is really subordinate to the types of agents which have been indicated in Lesson Thirty-Eight. In general, motions may be divided into two kinds, natural and voluntary, for every intentional agent (fā‘il bil-qaṣd ), providential agent (fā‘il bil-‘ināyah ), agent by agreement (fā‘il bil-riḍā ) and agent by self-disclosure (fā‘il bil-tajallī ) is a voluntary agent. Compelled agents (fā‘il bil-jabr ) and subordinate agents (fā‘il bil-taskhīr ) are also considered to be particular states of voluntary agents, just as the constrained agent (fā‘il qasrī ) is considered to be a specific state of the natural agent.

Among all the properties of motion, the most important thing about which the philosophical discussions of the categories of motion turn are the channel and the distance of motion. However, prior to the presentation of these discussions, it would be worthwhile to have a short discussion of a division of motion on the basis of differences in acceleration and at the same time to review the problem of the evolutionary nature of motion and its relation to acceleration.

Divisions of Motion on the Basis of Acceleration

Consider an automobile the needle of whose speedometer gradually increases from zero to one hundred kilometers per hour. It goes up, then stays there for a while, and then gradually returns to zero. This automobile is transferred during the period of its motion from pointA to pointB , and this motion is translative and occurs in the channel of space. However, in this process, two other gradual changes are observed. One is the change of the speed from zero to one hundred k.p.h., and the other is the change from one hundred to zero. From a philosophical point of view, this change is also to be included in the definition of motion. It may be considered a kind of

motion in quality, since acceleration and deceleration are two qualities specific to motion which are also accidents of the quantities of the speeds.

The same can be said for other types of changes or motions, so that one motion in quality may be attributed to another motion in quality from a different point of view. For example, suppose that a colorless body gradually becomes black and retains that state of blackness for a while, then its color gradually fades and it becomes colorless again. Undoubtedly, a change in the color of a body is a motion in the category of quality. It is possible that the degree of blackening or fading is not uniform through all parts of time. For example, the speed of blackening might gradually increase and then decrease in the same manner. This change in speed is different from the change itself in color, and for this reason it may be considered a motion which rides upon the other motion. Likewise, one may consider a constant motion to lack this sort of change, and its speed will be fixed.

Therefore, from the perspective of constancy or change in speed, motion can be divided into three kinds:

1. Constant motion without acceleration and a fixed speed.

2. Motion with increasing speed or positive acceleration.

3. Motion with decreasing speed or negative acceleration.

The existence of motion with increasing speed and of motion with decreasing speed and likewise of motion with constant speed are observed by the senses and are undeniable. One can even find instances of them by means of presentational knowledge, such as changes in subjective qualities and states which gradually increase and decrease in speed or are constant. Without a doubt, one may consider the decrease in the speed of a motion as a kind of decline, gradual weakness and imperfection in the motion. In this way a kind of weakening and declining motion is established.

It is at this point that we confront the question of whether the existence of slowing motion conflicts with some of the definitions of motion, such as, ‘the gradual emergence of a thing from potentiality to actuality’ or ‘the first perfection of a potential existent insofar as it is potential.’

In order to answer this question, two aspects of the discussion must be distinguished, one is the perfection of the motion and the other is the perfection of the moving existent.

It is possible that the moving object obtains new perfections through the course of its motion, while there are differences in the speed of these attainments. That is, in some times the speed of perfection may increase while at other times it decreases and at yet a third time this speed may be constant. The constancy or even the decrease in the speed of attaining perfection in no way detracts from the fact that the moving object is becoming perfected. For example, a body whose rate of blackening decreases will still be ever more black from one moment to the next, although the change in color will occur more slowly. Hence, there is no contradiction between the assumption that motion leads to the greater perfection of the moving existent and the assumption of a negative acceleration for the speed of perfection.

If someone were to claim that every motion becomes more perfect insofar as it is motion, this claim will not be compatible with the acceptance

of constant motion and motion without acceleration, and it is clear that such a claim will be contrary to introspection and self-evidence. Recourse to some definitions of motion will not enable one to prove such a claim. Furthermore, the mentioned definitions do not prove such a claim because at most what can be concluded from them is the fact that the moving existent under the influence of motion obtains new perfection and actuality, and as was indicated, the perfection of a moving thing does not conflict with the decrease of the speed of its motion.

The next question we shall take up is that of whether every motion leads to the perfection of the moving thing or not.

The Evolution of the Moved due to Motion

We have learned that the perfecting of motion, in the sense of acceleration and increasing intensity, is not universal. None of the definitions of motion indicate this. However, in the sense of the perfection of the moved under the influence of motion, it is possible to infer from the two mentioned definitions that since the moved achieves a new actuality and perfection by means of motion, it is necessary that every motion will be an intensification and lead to the perfection of the moved.

One who reasons in this way must confront a great problem: many things gradually weaken, wilt and perish. Their gradual change and motion not only fail to increase their perfections but constantly decrease their perfections, and bring them close to death and destruction. Plants and animals, after passing through the periods of growth and flourishing, enter the stage of old age and decrepitude, and their withering and declining motion begins.

In order to escape this difficulty they have sought to find an alternative in the claim that these kinds of declining and decaying motions are accompanied by the motions of other existents which are growing. For example, while an apple rots due to affliction by a worm, the worm grows in it, and the real motion is the perfecting motion of the worm, which brings about the decrease in perfection of the apple, and its wilting and rotting are its accidental motions.

Not only is there no way to prove that in all cases the declining motion of a moving thing is accompanied by the intensifying motion of another moving thing, but also one cannot ignore the gradual declining change of an existent and dismiss it as ‘accidental.’ Finally, this question remains, what is the philosophical significance of this gradual declining process in the wilting existent?

Reliance on the mentioned definitions in order to deny non-perfecting motions cannot explain their undeniable existence. Assuming that the purport of the definitions is not compatible with declining motion, one must raise doubts about the correctness and universality of the definitions, instead of relying on the authority of the definitions to justify something which is unacceptable. At the same time, however, it is possible to interpret these definitions in such a way that they do not imply a denial of non-perfecting motions.

As was explained in Lesson Fifty-Two, actual and potential are two concepts which are abstracted by comparing the priority of one existent to

another, and the inclusion in the second existent of the whole or part of the first existent. This by no means implies that the second whole is more perfect than the first. Likewise, considering the motion to be a preparatory perfection for the attainment of a major perfection does not imply the perseverance of all of the previous perfections in the present existent, for it is possible that a requirement for motion and the attainment of a perfection whose conclusion is being considered is that the moving object must lose some of its other perfections. The perfection which is obtained as a result of motion may be equivalent to or even less than the lost perfection.

Therefore, the correspondence of Aristotle’s definition to various types of motions does not imply that the perfection which is obtained through motion is ontologically superior to the perfection lost by the moving object. It cannot be concluded that the moving existent necessarily becomes more perfect, comparing its present station with its previous condition.

It is not basically necessary to depend on the concepts of actuality and potentiality and the concept of perfection in the definition of motion, for these concepts, which themselves are in need of explanation and interpretation, cannot remove any ambiguity from the concept of motion.

Is it really acceptable to say that everything which moves from one place to another thereby becomes more perfect and attains new perfections superior to those it had possessed? Can it really be proved that the wilting and declining processes of every vegetable and animal are the results of the perfection of another existent?

Perhaps it will be asked, if motion does not bring about the perfection of the moved, then why does the moved undertake the motion? What motivation could it have?

The answer is that, first, not every motion arises from the consciousness and motivation of the moved, as was mentioned regarding natural and constrained motions. Second, it is possible for a conscious existent to perform a motion in order to attain a real or imaginary pleasure, but out of negligence for the natural consequences or due to the intensity of the desire for the mentioned pleasure, this motion leads to the loss of more valuable perfections. Anyway, the irrationality and imprudence of such a motion does not imply that it is impossible.

It is possible to say that if the resultant of the motions of the world is not positive and that the result of the collection of all their motions is not the obtaining of more perfection for existents in this world, then the creation of such a world would be vain and useless.

The answer is that on the basis of divine wisdom we can prove that the creation of the world is not vain and useless and its results are wise. However, the positive character of the resultant of the motions does not imply that every motion necessarily is perfecting and causes more perfection for the moved itself.

It may be concluded that there is no reason to hold that every moving thing under the influence of motion achieves a perfection superior to its previous perfection, regarding its ontological level. Innumerable experiences show that not only is there constant motion, but also declining and weakening motion exist, in the sense that the moved gradually loses its

present perfections or possesses perfections which are not superior to those it has lost. If some definitions of motion are not compatible with such motions, they must be considered to lack universality. The perfecting character of every motion can be accepted only in the sense that the existence of the moving thing attains to something existing, which it previously lacked, although it previously may have possessed something similar or more perfect, as was mentioned regarding the relation between the potential and the actual.