SUMMARY OF PHILOSOPHY OF NATURE

Causes and their relationship with Science

Man has always made efforts to acquire knowledge in science and nature. We seek a cause, a reason that will explain why things happen the way they do and are the way they are. Also, why things are formed the way they are.  It is our desire in this paper to consider the causes in nature and their relationship with science.

            A Cause simply means ‘that which produces an effect; a person or thing that makes something happen. Again, it may mean ‘the reason for something; a factor that justifies something; an aim, a principle or a movement that is strongly defended or supported. Cause is necessary in nature because the three principles of nature are not sufficient for generation

According to Kenny, science is a technical term for knowledge of a determined subject, an attribute which is the property of that subject and the cause of that attribute. It is the knowledge of universal fact through the proper causes. Such scientific knowledge according to Aristotle is attained through inquiry into objects that have principles, conditions or elements. Science is demonstrative because it is knowledge of the fact with proper and justifiable reason for the fact. To gain this knowledge, a thorough analysis of this knowledge gained through experience and research is made to its simplest form.

Kenny opined that to be acquainted with natural science, the knowledge of the sequence in order of procedure is needed which consists of principle, cause and element. He emphasized causes, identified them as four with their meaning as follows:

Ø  Material cause: It explains what a thing is made of.

Ø  Formal cause: Explains the form a thing assumes

Ø  Efficient cause: Explains the process by which a thing came into being. They are prior conditions, entities or events considered to have caused a thing. They are the primary source of change (motion) or rest. It is that which brings something about. They explain the process by which a thing came into being.

Ø  Final cause: Explains the purpose a thing serves, that, for the sake of which the efficient cause acts. The intention of the agent.

With these divisions, Kenny stated that natural science deals with both matter and form since both are nature. The form of a thing is actually the end (final cause) of matter of that thing. Once the thing is changed, the form changes and vice versa. The final form dictates what will be done to the matter. The use of a thing (final cause) determines the form it will take and the form in turn, determines the matter. He added that natural science which is our interest here uses all the causes. Since science is knowledge by causes and it is by knowing the cause that one is able to see and explain why a conclusion is true, therefore the knowledge of the cause is by induction important in scientific knowledge acquisition.

Furthermore, Aristotle adds that natural science deals with natural things and not artificial things. Things whose source of activity or principle are their own intrinsic nature and have the principle of motion within them are natural. Yes, some things around us are natural, others are artificial otherwise they are designated by chance. Those that are natural have in themselves some principles of motion and rest. On the other hand, artificial things do not have such a principle of motion but only of that which possess them. Thus, the basic difference between natural and non-natural things is the virtue of having the principle of motion within the natural which artificial things do not have.

            Prompted by this understanding, one may conclude that in natural science, knowledge is derived through inquiry into the cause of a thing. Therefore, the knowledge of the cause is by induction important in scientific knowledge acquisition.

The second chapter of Aristotle’s Physics presents us with the principles of nature

Conceptual clarifications

Things in nature involve processes and stages before they are generated. Some terminologies have been attached to them to expose their meaning as well as identify them.

Prime matter: this is pure potency. It is the substantial underlying reality of all things, and as such has the potential to become anything. It has no physical appearance, quality or quantity. It has no form and therefore cannot be known. It is that which is in potency for substantial existence. It has no form or privation but subject to them. There is no other matter before it.

Potency: These are those things which can be but are not. It is the ability of a thing to achieve a determinate end.

Act: These are those things which already exist. It is the acquisition of the form by matter.

Element: it is that material cause for which a thing is primarily composed of, which is in that thing and is not divided by the form.

Existence: Whenever the matter takes a form, there is existence. Form is that which gives existence to matter and because form causes existence in act, therefore form is the act. There are two forms of existence: Substantial existence which is “matter from which” existence begins and accidental existence which is “matter in which” accidental changes can take place without affecting the subject. Substance (subject) is the being while predicates are on it. The subject has already a complete existence but can only experience accidental change. Man is a substantial existence while man’s colour is accidental.

Generation: this is the movement to existence. It is a change from non-existence to existence and a change to form. It takes place from a non-being which is in potency to being while Corruption is the movement from existence to non-existence. Matter and efficient causes are absolute necessity for generation while conditional necessities are causes after generation i.e. completeness which are end and formal causes

There are two forms of generation: Those things that come into being and are called generation simpliciter which is the substantial form and the things come into being as something and are called generation secundum quid which is the accidental form. It is already in being, but the changes that take place in it are accidental changes. There three conditions for generation which are matter, privation and form.

Principles of nature: There are three principles of nature: matter, form and privation.

Matter: This is that which receives the form. It is that in which the privation and the form are understood. It is the being in potency. That matter which does not imply privation is permanent but that which implies it is transient. It can never exist by itself and is not completely without any form or privation. It is that in which generation takes place. It is a passive potency for it receives the form and cannot act. Without the matter, the form does not exist, but matter receives the form. It is the content of a thing. It cannot be completely without form or privation.

Form:  This is the structure and function of a thing. It is what allows prime matter to become substance. It is an active potency. It brings existence to matter and matter cannot be known without the form. Once there is form, the matter is in existence and known. It is through it a thing comes to be in act.

Privation: privation is a principle which qualifies the matter. It is the proper potency/aptitude for a form and leaves once the form comes which makes it not to be among the causes. It is seen in becoming and not in existing. It is non-existence in act. Matter is never entirely without privation which makes privation necessary for generation. In fact, it is same in subject with matter but differ in definition. It is a per accidens principle because it is coincident with matter and without it, the matter will still be in existence. Privation is necessary for generation because it qualifies the matter and describes the form it takes.

N:B Matter is prior to form from the point of view of generation and time but the other way from the point of view of substance and completeness. Material and efficient causes are prior by way of generation while formal and final causes are prior by way of corruption.

Assignment: The subject of Natural science

Nature is the principle of motion and rest in that in which it is primarily and per se and not according to accident. Nature is defined in terms of motion. Some things around us are natural, others are artificial otherwise they are designated by chance. Those that are natural have within them some principles of motion and rest like growth, local motion and qualitative change. We discuss the principles of motion because there is plurality of being and plurality of motion. Principles are not infinite but finite otherwise we cannot know them.

            On the other hand, artificial things do not have such a principle of motion but only of that which possess them. Thus, the basic difference between natural and non-natural things is the virtue of having the principle of motion within the natural which artificial things do not have. Nature is only in natural things. The following characteristics from the definition constitute natural things:

Ø  Principle: This is an intrinsic (inherent) property of motion that enables it to act or be acted on. It can either be active (fire burning) or passive (magnet moving an object). Matter, form and privation are the principles. Considering nature as form, in the active sense, it acts on another while in the passive; it initiates self-motion (gravity). But as matter in nature, it is passive for it receives motion from the form.

Ø  Motion and rest: Nature causes something to move and makes it also to remain at rest when it reaches its proper place.

Ø  In that in which it is: have the nature of their own, and not on others nature like machine

Ø  Primarily: the composition, the generic nature of the matter

Ø  Per se and not per accident. It has substantial components.

Nature is Self-evident: the existence nature is not demonstrated, but evident.

Nature as form and matter: However, in another sense, some people saw nature as matter considering it as the subject and constitutive part of natural things but this was false if matter is considered as the whole substance. They see matter as the basic fundamental stuff in nature which may be either one or more than one like air, fire, water, and earth since they have always been in existence and may always be. Potency and matter are not the nature of a thing. Others consider nature as form because the actual thing does not come into being until it receives a certain form. Form gives identity and actuality. Therefore, matter is nature, form is nature and what comes out of them is a composite of nature being a product which indirectly i s part of it. But since the identity of a thing comes more from its act than from its potency, nature applies more to the form than to the matter even though both are nature. For Aquinas and Aristotle, nature takes from both matter and form in contrast of earlier philosophers that considered nature primarily in terms of matter alone. Form is the end of matter and that is why nature is considered as form and matter. But nature is considered in so far as there is matter.

Natural science differs from the other sciences in the following ways:

Mathematics: Mathematicians may begin from sensible matter and terminate in abstract and define their terms without motion or matter while natural scientists definitions comprise sensible matter.

Mixed sciences: They begin from the abstract and terminate in sensible matter. They are not purely natural but demonstrate their conclusions by another middle term unlike the natural sciences.

Natural science: it deals with both matter and form since both are nature. The form of a thing is actually the end (final cause) of matter of that thing. Once the thing is changed, the form changes and vice versa. The final form dictates what will be done to the matter. The use of a thing (final cause) determines the form it will take and the form in turn, determines the matter.

On the issue of chance, some argue that there is nothing like chance but attribute everything to predetermined causes , others say everything happens by chance while others added that chance is by divine reason i.e. divine providence. But for Aristotle, chance is anything exceptional to the rule. Things in nature are regular acting in the same way unless impeded, but chance are unintended, unforeseen and exceptional. Chance is defined as the accidental cause of exceptional or unintended results of choice or nature acting for another purpose. It is called fortune or luck when it concerns human beings and can be reduced to efficient cause. Some things around us are natural, others are artificial otherwise they are designated by chance. Impediment of nature results to chance. Aristotle’s view on chance is that once you hold that everything is by chance, there cannot be science.

Assignment: Motion as construed from an Aristotelian- Thomistic tradition.

The relevance of this topic to the study of this course lies in the fact that nature is considered as “a principle of motion and change”. Because of this intrinsic relationship between nature and motion, it therefore becomes obvious that for a correct understanding of nature, a similarly correct understanding of motion is imperative and indispensable. These facts are illustrated in Aristotle’s Physics (Book 3, Lesson 1) and Aquinas commentary on Aristotle Physics (Chapter 5).

Definition of motion

Since natural things are either in motion or at rest and such things in motion can only be defined in potency and act, Aristotle condemned the definition of motion by some people that motion is “a going out from potency to act which is not sudden”. They placed attributes which comes after motion in the definition. Going out (e.g. local motion) comes after motion and sudden related with time. Considering that act and potency are prior to motion, he thereby used them to define motion thus:

Ø  “As the act of what exist in potency, in so far as it exists in potency". Therefore, it is neither the potency of a thing existing in potency for some things are actually in potency, nor the act of a thing in act. But, it is the act of a thing in potency where the word “act” designates its relation to a prior potency and the words “of a thing in potency” designate its relation to a further act.

Ø  As the act of a mobile in as much as it is mobile. Since motion is the act of a thing existing in potency in as much as it is in potency, and as much as it is in potency, and since that which exists in potency as such is the mobile and not the mover (for the mover as such is in act), it however follows that motion is an act of the mobile as such. But movers are also in potency of moving the mobile and being moved because its movement is concurrent with the mobiles. Since what the mover causes by acting and what the moved receives in being acted upon are one and the same thing, so, motion in so far as it proceeds from the mover to the mobile is an act of the mover (action, efficient cause: act of the agent) but in as much as it is in the mobile from the mover, it is an act of the mobile (passion, effect: act of the patient).Therefore, that which has the power of causing motion can only act in reference to a thing capable of being changed and brings with it some elements of form.

Ø  The fulfilment or transition of a thing from one point (real and imagined) to another, either from its qualitative, quantitative, substantial or spatial form. This possibility of natural things to change is grounded in the principles of nature (form, matter, and privation), efficient causality and final causality. Thus, to set a thing in motion means to cause it to pass from potency to act. The implication of this principle is that only a thing which is in act can bring another from potentiality to actuality. Hence, motion is as such necessarily contingent upon a subject’s lack of a certain form (privation) which it is capable of receiving and an agent possessing the perfection it is about to produce. Motion can’t exist apart from what moves, there is no abstract motion.

In conclusion, for motion to be possible, it must occur midway between things that are in act and in potency. Motion involves a relationship between extrinsic efficient cause and its object. Fundamentally, a thing that moves is moved by another which by virtue of that function must be an act.

Assignment: Infinite as construed from an Aristotelian- Thomistic tradition.

Philosophy of nature is concerned with the universal causes or principles in the mobile world of natural sciences. Having treated Motion in the last class, a look at the infinite is expedient for a better understanding of nature and continuity of motion.

Motion as was explained earlier is the act of what exists in potency in so far as it is in potency; thus, motion takes place mid-way between potency and act. According to Aristotle, Infinite exists as something in potency; it is that which is not to be entirely in act or be in act at once, but can be in act part after part. Infinite is that beyond which there is always something. By something here, I suppose that Aristotle implies the continuous act (motion) which goes on in the thing moving it to something beyond its present state. It is an intrinsic property of motion.

The following qualities and characteristics can be said of a thing that is infinite:

Ø  In a thing, it is more of parts than a whole since it is not meant to be entirely in complete act but ever actual.

Ø  It is in potency, imperfect/ incomplete and comparable to matter in perfection.

Ø  It is partly in act and partly in potency like motion

Ø  It can be said to be unknown because it has no complete form. That which has a form has a body which makes it known and is limited by a surface which is finite.

Ø  Infinite consists in privation and the per se subject of this privation which constitutes the nature of the infinite is sensible continuum.

Ø  Thus, it deals with continuity and sensible things

Ø  It also deals with magnitude (divisible) and denumerable i.e. numbers can be added to unto infinity and these are infinite in potency.

Ø  Infinite of magnitudes and numbers is the finite actualization of something that can always be further actualized by division and addition.

In conclusion, since anything that is infinite is supposedly in motion i.e. it is inherent in motion being that motion is the act of that in potency in so far as it is in potency; and motion is continuous, therefore, infinite is necessary for motion, act and nature. Sensible things have infinite in the finite only in potency but such things are finite in act. This is potential infinity. Actual infinity is that beyond which there is nothing and is not experienced in nature such cannot move. That is why God is infinite

Assignment: Place, Space, Void as construed from an Aristotelian- Thomistic tradition.

Nature deals with the principles of motion and since the intrinsic part of motion has been discussed, it is our desire to summarize the extrinsic parts. But the first three extrinsic factors to consider here are place, space and void.

PLACE: Place is considered in this course because, for there to be motion, things move from one place to another or alter (increase or decrease) in place. Place therefore is

Ø  A place “from which” and “to which” of local motion

Ø  the immobile surface of that which primarily contains a body.

Ø  what contains that of which it is the place while remaining distinct from it.

Ø  the immediate place of a thing i.e. the immediate boundary of a thing.

Ø  it is the boundary of the containing body, while the contained body is what is apt to be moved in respect to place.

Ø  can be left behind by the thing and is separable

Ø  the innermost motionless boundary of what contains.

Ø  Constant and does not change.

Everything in place has a place although the thing can move from one place to another which is called motion. Place takes precedence to the thing because it can exist without the thing but the thing cannot exist without it and place does not pass out of existence but the thing does. Therefore, every sensible thing is in place. Place is of two kinds- primary (proximate) place which is our immediate surroundings and common place which is the larger area where we happen to be. There are various arguments for the existence of place, some support and others oppose insisting that place does not exist.

Reasons for the existence of place are: (1) From local motion: Generally in local motion, there is change of place and things move from one place to another for motion to take place, showing that there is place. (2) From proper place: Here, we consider the destination or variation of place either ‘up’ and ‘down’ or ‘right’ or ‘left’, the increase and diminution of a thing shows that place exists. (3)Void and space: Since in or around a thing, there is a place devoid of anything, therefore place exists. Some Philosophers have raised arguments against the existence of place but the existence of place is expedient for local motion.

Space:  It is seen as an absolute dimension that does not change. Like the four dimensions of a room. It does not change the dimensions of the body that fills it. In fact, it does not affect the state of the body. it is the generality of places but when marked out, it becomes a place. Some philosophers argue that there can be neither duration nor succession in space.

Void: For some Philosophers, change of place would be impossible without void. Since there is motion in nature, it follows that there should be void to receive the thing being moved because a thing cannot be moved into what is full otherwise there will be two bodies. Place is in a space while a thing is in a place. The remaining part of a place in a space not occupied by the thing, is the void. There is still void for compressible things to allow for compression. This is a place in which there is nothing i.e. no object. But for Aristotle, nature abhors vacuum and it is difficult to get void in nature. So, void does not exist.

In conclusion, Place is different from Space, Void, Form (it is intrinsic), Matter (becomes one with the thing) and Vessel (can be moved) and should not be considered to be the same. Therefore, Place according to Aristotle is the immobile surface of that which primarily contains a body, it is the surface of the containing body. With this, place is important for local motion to take place. In fact, motion is the rate of change of place.

Assignment: Time as construed from an Aristotelian- Thomistic tradition.

Time

Time is one of the extrinsic principles of motion. But the question is, does time exist? What is its nature?  What is its relationship with motion? These questions we shall address in in this paper. Time can be considered in the following ways: Time

Ø   is in the numbering of motion according to before and after i.e. as it crosses different points of place.

Ø  is a measure of motion, basically, local motion in its duration essentially (hours, days) and also in its being (continuous and numerable).

Ø  is also a measure of rest for those things that are not moving but have motion at a point. Therefore, time is everywhere both in things in motion and those at rest.

Ø  is composed of some parts which have been (past), others which have to be (future) and  the no part which is (now). Therefore, past and future do not exist.

Ø  Is applied in terms of ‘now’ in so far as it is not always the same but in as much as it is the conception of ‘before’ and ‘after’ (i.e. events succeeding one another from the past, through the present to future). The ‘now’ is a point in time, an instant, a moment. Time is known through the now. Now is the various points in the difference between the before and the after. The culmination of those instances makes up the time. That is why now seems to be continuous and a boundary of time. E.g. he has now come, he came at 2:00pm, it happened then. In its strict sense, now is the end of the past and a beginning of the future making it continuous. In fact, it measures time and if there is no time, there is no now and vice versa. Now is our most immediate experience of time and once experienced, ceases to be but becomes past. Now distinguishes the past from the present. It points to a moment, an instant.

Ø  is divisible.

Ø  talks about how short or long an event lasts when it occurs in so far as it is a continuum and much or little in so far as it is a number.

Ø  As a number (much or little), the minimum is one e.g. a year, day or second. But as a continuum (long or short), it can be divided into smaller parts just like magnitude.

Ø  is linked with movement  that is something in motion and change

Ø  is that by which movement can be numerically estimated. Movement is measured by the time and time is measured by the movement, they define each other.

Ø  enables things to change; therefore, there is change because there is time.

Ø  cannot be pointed as an actual thing, are not extended in space, not sensible objects and has no location.

Ø  deals with events. Without events, there is no time because in talking about time, we talk about temporal sequence of events within space. It is the duration of events.

Ø  is related to event in that events make time but there is no event outside now which is always in the past. The future is not an actuality.

Ø  Is the same everywhere but different due to the event by reason of before and after

Ø  Can be repeated (duplicated) because of the specific repetition (rainy season) of the motion (event).

Ø  It is infinite in potency but finite in being. It is a continuum but discrete in relation to motion and events.

In conclusion, Time is not identical to motion but linked with it. It is not motion (because motion exists in particular things that are in motion but time is everywhere). Time does not exist without motion. It is connected with motion. Time is in the numbering of motion according to before and after. Time cannot be applied unless there is succession of events, which is the beginning of the event to the end of it. It is the number and measure of motion. Because there is a priority and posterity of motion, there is a priority and posterity of time. It is not a motion of the mind. Whatever is contained in time is subject to decay and corruption, but whatever is outside time exists forever.

Eternity has to do with endless life. There is no event in it either before or after and it does not begin or end. Only God is eternal. Time is not eternal but eternity is the cause of time and is therefore not in time. Whatever is in the visible world must have a beginning which is the beginning of motion and time. Time began when nature came to be i.e. creation. Creation was the beginning of time. Therefore, motion and time came into being when nature began and are not eternal and whatever is subject in time is subject to decay and corruption but that outside time exists forever and is no longer in nature. But evolution is in time, it is a change of form.

Assignment: The kinds of motion and their contrariety.

            The impart and importance of Motion on natural things makes it paramount to discuss on the different kinds of motion and their contrariety. What are those requirements for motion? Does every category in nature admit motion? Can motions be contrary? These we shall be discussing in this paper.

            According to Aristotle, since motion is defined in terms of its terminals, there are five basic requirements for motion. These are: that which directly causes motion (efficient cause or a mover), that which is in motion (the mobile or subject of the motion), that in which motion takes place i.e. time in which the motion occurs, a starting point or terminal of the motion, and that to which motion proceeds (the end point or terminal of the motion), since every motion proceeds from something into something. He postulates that there are different kinds of changes with respect to the terminals. He identified the changes associated with generation and corruption as not being motion because they are instantaneous while motion is continuous. Change from a non-subject to a subject takes place between contradictories and is called generation (non-red to red, non-man to man). Generation is not motion because what does not exist cannot be moved, and if it exists it is already generated. Change from subject to non-subject is also between contradictory terminals and is called corruption (red to non-red, man to non-man). Only the change from subject to subject (i.e. two affirmative contraries or intermediaries) is motion i.e. from a being to another being which signify two terminals (black to white).

Expatiating, Aristotle asserts that among the ten categories in nature, there are only three that admits motion, thus, quality, quantity and place. It follows therefore that there are three kinds of motion which are: qualitative motion called alteration, quantitative motion seen in increase and decrease, and motion in respect of place or locomotion (local motion) and continuity and contrary extremes exist in them. 

On the contrariety of motion, Aristotle argues that motions are contrary much more by reason of their attained terms than by reason of their relinquished terms. He states that contrary motions are those which have contrary terminals, i.e. motion from a contrary to its opposite contrary. They touch at one or more points and traverse through a number of betweens (points arrived at, no complete stop even though there is go-slow) before the extremes making them to be one but at the same time contraries. It refers to the two different extremes that motion takes place. The time should be continuous and uninterrupted for there to be contrary and continuous. Also, since rest is a privation of motion, it can be seen to be a contrary

When the end points of species are one i.e. touches, continues and become one, they are said to be continuous. But when they touch, don’t continue and becomes two actual points, it is contiguous.

In conclusion, there are three kinds of motion, namely, qualitative, quantitative and local motion and each of these motions possess a pair of contrary extremes (terminals).

Assignment: The divisibility of Motion.

Aristotle argues that motion is divisible. Is motion truly divisible and what makes them divisible? This shall be our aim in this paper. Since motion has been described in the early presentations as a continuum, if it is a continuum, is it really divisible or indivisible?

According to Aristotle, those things that are composed of parts have extremities that are one or together. Thus, those extremities that are one are called continuous (continuum) while those that touch themselves without being in constant movement are contiguous. Continuous things are those things which are composed of points which do touch one another, continues in motion or rest and do not break. Consequently, motion is continuous.

Aristotle argues that, in continuous things, there will always be the existence of two points, the first point where the thing moved from to where it is moving or moved to. Since there are two points for a moving object, it therefore follows that there will be difference in position and time for continuous things where the change in position is associated with magnitude.

However, since magnitude and motion are correlated, he opines that magnitude is divisible because of the difference in positions for a moving or moved object. He thereby added that motion is divisible since magnitude is divisible.

Furthermore, as it has already been established that time is considered as before, now and future and ‘now’ as that which terminates the past and begins the future which is not contiguous but continuous since time is not an aggregate of indivisible ‘nows’. A particular ‘now’ is indivisible and therefore has no motion. Does it then means that there is no motion in time since time is considered in the ‘now’ which is already past? He answers that considering that there is difference in the ‘now’ and a former ‘now’, then the time between the two ‘nows’ are divisible. Motion resides at this time between the two ‘nows’. Motion is accordingly divided to time since there is difference in time and less motion in less time and vice versa. Therefore, since time is continuous and divisible, motion is also continuous and divisible according to him.

Aristotle therefore teaches that Motion is divided according to the motion of the parts of the mobile object. But the beginning and end of motion are not divisible. Just as motion is continuous and divisible, so rest is continuous and divisible.

Assignment: The First (Unmoved) Mover

            Since it is an already established fact that whatever is moved must be moved by another, it is our view in this paper to present that there is a first unmoved mover who causes motion and is in itself unmoved who is called God.

According to Aristotle, in a series of moved movers, the last thing that is moved and the moved movers are being moved together like coaches in a train. They are moved simultaneously, at the same time and are continuous which makes them seem to be infinite. This is because generically in nature, it is possible for most things to be joined together in one enormous continuous body.

 However, Aristotle asserts that since everything that is moved is moved between two termini, the motion of the infinite mobile objects is finite. There is a finite motion in the whole series of motion. Secondly, in his postulation of series of motion, he posits that there cannot be an eternal series of motion because basically, there will be a first mover and a first moved in the series. Though there are different causes of motion in the series, there is an ultimate cause of motion which though causes motion but is itself uncaused and unmoved. If there is something which is moved by another, it is necessary to come to a first that is not moved by another to be able to experience motion. Thus, we must come to a first unmoved mover and if this first does not act, the last does not act and there will be no mover or moved. Therefore, the first moving cause in the whole universe must not be moveable even per accidens.

In view of the fact that there is no infinite series of moved movers and there is immobility of the first mover from the perpetuity of motion, Aristotle views the Eternal as the “Prime Mover” and “Uncaused Cause” and this Prime Mover, Aquinas calls God. For Aristotle, therefore, there is a single continuous perpetual motion which accounts for and is prior to all earthly generation and corruption and that is the Unmoved mover.

Finally, the Unmoved Mover is the first mover in the series of movers. He is not in motion but imparts motion, and as such, he is the ultimate Cause of motion. And if he does not act, there will be no motion as he is the initiator of motion. He is known as God.

Notes

For those natural things which don’t have in themselves the capacity to move i.e. inanimate things, an impetus is given to them for motion which keeps it going. But the impetus does not last forever. E.g. projectile. So to be moved requires a mover, the mover imparts the impetus.