I
THE science of local motion is fundamental in natural philosophy. Locomotion is the primary kind of motion; it is generated last of the three kinds of motion so that in order of being it is first, as the Philosopher has observed. Thus, owing to its primacy, a proper knowledge of the nature of local motion is necessary for a full understanding of the first of the five ways by which St. Thomas establishes by reasoning the existence of God as the Author of Nature, namely, the argument from motion in the world. In the philosophia perennis, unfolded by Plato, Aristotle, the later Greek and Roman philosophers, and the Jewish, Arab, and Christian doctors of succeeding ages, motion is recognized as a transition from a state of potentiality to a state of actuality; further, such a transition to actuality can only come about by the influence of something already in a state of actuality; hence we have the principle that whatever is in motion must be moved by another. This principle illuminated the sciences of Nature and guided philosophers along sure paths during those ages in which the philosophia perennis was the inspiration of all but a few eccentric and misguided individuals. However, since the revolution in physical science in the seven¬teenth century and the appearance of sciences of Nature alien to the philosophia perennis, an entirely different doctrine con¬cerning local motion has generally prevailed. Newton's first law of motion lays down that every body in the universe continues in its state of rest or of uniform motion in a straight line unless compelled by external force to change that state. On Newtonian dynamics a freely moving body does not require an external mover; a mover is required only to change the motion of the body, i.e. to cause acceleration, not to continue its steady state of motion; the Newtonian theory of locomotion thus evokes the principle of the inertia or impetus or momentum possessed by bodies. Newton's doctrine is thus quite at variance with the doctrine of Aristotle and St. Thomas according to which a moving body must be moved continuously by another agent if its movement is not to cease. The Newtonian system was not wholly new; it was rather the definitive form of doctrines of motion which were pro¬pounded in the fourteenth century by Jean Buridan, Nicolas Oresme, and others of the University of Paris; doctrines which became ever more widely disseminated until their final triumph in the seventeenth century with Galileo, Descartes, Newton and hosts of others who participated in the élan of the times. These doctrines of motion are quite foreign to the philosophia perennis; with the triumph of the impetus doctrine in the seven¬teenth century came the general abandonment of the traditional doctrine of motion; the ancient science of nature with its rich patrimony of so many centuries henceforth found no hearing in the universities of Europe; the ancient learning was preserved in obscurity by a discriminating few, for the most part in the seclusion of the cloister, while the learned world followed new and seductive paths. Further, not only were the Aristotelian doctrines of motion abandoned in the seventeenth century, but the whole frame¬work of the philosophia perennis was given up at the same time by the generality of philosophers, and indeed has remained in general oblivion to this day. There are no doubt many reasons for this great seventeenth century tidal movement in philosophical opinion, but prominent among them is this: it was believed very widely that the experimental physics of Galileo and Newton had overthrown the Aristotelian physics, and it was further generally believed that this defeat in the field of physical science was of such a fundamental character that the whole Aristotelian system was thereby rendered untenable, and that other philosophies of the world must be sought. The science of motion was certainly not the prime mover in the philosophical revolution; for that we must look deeper; but the doctrines of motion precipitated this revolution and confirmed it in popular estimation even to our own day. The science of local motion is thus of the greatest import, not only intrinsically but also historically in understanding the sway which these philosophical vagaries have exercised during the last three centuries. We shall now examine the doctrines of local motion, and in particular the general principle that what¬ever is moved must be moved by another. The Two Doctrines of Local Motion. Our first general inquiry will be directed to this question: does the physics of Galileo and Newton truly render the Aristo¬telian physics of locomotion untenable, or does the common belief that this is the case rest on a misconception of the respec¬tive natures of these doctrines? There are several matters which must be considered: (1) The principle that motion requires a constant mover is of such a general character that it does not depend on any particu¬lar theory of locomotion. Motion means the transition from potency to actuality, and this can only be brought about by something already in a state of actuality. Thus, for instance, we heat a pot of water by placing it on the fire; again, a man cannot teach arithmetic to another unless he already knows arithmetic himself. This contention is so fundamental to the world that it may justly be termed metaphysical rather than merely physical. It belongs to a higher and more general order than the particular processes of physical science; it does not rest upon the latter, but rather the particular doctrines of the special sciences flow from the general principle. To trace the operation of our general principle in its rami¬fications in local motion will lead to a deeper understanding of local motion, since the inner springs of that motion will thereby be made manifest. (2) We have discussed elsewhere the doctrine that the system of physics inaugurated by Galileo and Newton is only prima facie physics in the proper sense of that science, namely, an inquiry into the physics or nature of things. According to this contention (which will be one of the bases of the present inquiry into motion), physics since Galileo has been progressively detached from the family of the real sciences and no longer has any community with the head of the family, namely, metaphysics. A science so detached we shall henceforth designate as Kantian. The structure of modern Kantian physics has been built up as an elaborate tour de force with its own autonomous domestic economy, and with a goal which is ultimately pragmatic. The laws and principles of Kantian physics are imposed on Nature by the physicists, and are not found in Nature; they are not the real principles of Nature any more than the patterns of the formal gardens of Versailles or the conventional lines of latitude and longitude on a map represent Nature. Consequently, the fact that Newton's laws of motion are fundamental to modern physics does not establish these laws as the laws of Nature. Hence the general principle that motion in the world requires a constant mover is in no way invalidated by the existence of a prima facie conflict between this principle and Newton's laws of motion. The conflict is only apparent, not real: the metaphysical principle pertains to the real world, the Newtonian principle to an artificial world. (3) In investigating the nature of local motion we shall not be able to derive immediate assistance from the physical theo¬ries which have been entertained since the days of Galileo, for the reasons mentioned in (2). However, these systems are not wholly fruitless for our purpose. The systems of modern or Kantian physics being mosaics drawn from a variety of sources, they frequently contain disjointed fragments and echoes of metaphysical doctrines. Moreover, if we inquire closely we can often find devious connections of an indirect kind between the modern systems and the nature of the world. Consequently, although we cannot directly draw upon the theories of Kantian physics to formulate the science of loco¬motion, yet we may draw instructive comparisons and illustrations from these various theories. (4) It might be thought that the highly mathematical char¬acter of so many of the laws and theories of modern physics would preclude any significant comparison with the non-mathematical peripatetic physics. Further reflection, however, sug¬gests that this is not really so, since the mathematical character of the modern laws would appear to be not so fundamental and distinctive as it seems at first sight. Thus, the essentially quali¬tative and non-mathematical field theories of Faraday are exactly equivalent to, and may be completely transformed into the mathematical system based on the inverse square law of force. The mathematical theory, in spite of its semblance of a different nature and greater precision, is rather only a different language, and in truth has no more content that the non¬mathematical theory. It seems likely that a similar equivalence between qualitative and quantitative theories extends to all branches of modern physics, although it has not everywhere been yet unfolded. Hence we need not be deterred from a tentative juxtaposition of mathematical and non-mathematical principles. (5) The primary laws of a Kantian physics, such as Newton's laws of motion, rarely or never fit into Nature as they stand. Consequently, along with the primary laws we almost invariably find an array of secondary modifying rules which are designed to bridge the gulf between the laws of physics and accepted phenomena. The bridging of the gulf in modern physical science is somewhat analogous to equity in law: that which bridges the gulf between the law of the State and the norms of natural Justice. Thus Newton's laws in their simple form are immediately modified for terrestrial motions by such secondary rules as Stokes’ law for the movement of an object through a viscous fluid. Without these appropriate adjustments the primary laws could not seriously be entertained. In comparing our physical doctrine of locomotion with Newtonian theories, these modifications of the latter by secondary principles will assume considerable significance. (6) The physics of locomotion in the proper sense will be a fundamentally more coherent and ordered system than the Newtonian theory of matter and motion. The real physics is grounded on reality and illumined by universal principles; the Kantian artifact physics lacks a nature proper to itself and is an inherently mutable and contingent structure enjoying a human rather than a natural authority. It is not to be supposed, however, that the separated physical system is wholly errant like the Prodigal Son; it has a charter, that of pragmatic success, and its separation for this purpose is quite legitimate. Even with this charter, however, modern physics, cut adrift from the steadying hand of a paternal meta¬physics, is ordained to pursue mutable and airy paths to its limited goal, in contrast to the permanent and substantial paths of real physics. The pragmatic goal of the modern systems is less exacting than the ontological goal of real physics. In the real physics a dazzling excess of light from nobler natures or a lack of power in the human intellect to penetrate earthly obduracy may render progress difficult. Hence the spectacular but shallower successes of the modern systems while the real physics has con¬tinued its sober disciplined inquiries in cloistered seclusion. We distinguish in order to unite and thus we bring the separated sciences back into their proper places in the family of the sciences. The State of the Question. Since the seventeenth century the science of Nature has been obscured and discussions of the subject vitiated by the promiscuous mixture of theories and doctrines belonging to different orders, so that today this science is in a more confused condition than it was when left by St. Thomas. By distinguishing the different orders we remove this confusion and restore the true doctrines of Nature to their proper authority. The wealth of observation of Nature which has accumulated in recent centu¬ries has not yet been properly made use of to enrich the real science of Nature. Our inquiries into locomotion will be a first step in this direction. The course we shall follow is historical. In general we may regard the history of physics in one of two ways: We may re¬gard past physical doctrines as merely the debris in the evolutionary march of physical science towards greater conquests of Nature; or we may survey the whole field in such a way that the history of physics becomes comparative physics: this is a science like comparative anatomy or comparative law. We invoke the comparative science here in order to reach a deeper understanding of the physics of locomotion. The Impression of the Agent on the Subject. When we throw a stone it continues to move after it has left the hand; this suggests the necessity for a general inquiry into the persistence of impressions made on a subject by an agent. St. Thomas discusses this matter in various places. Thus, he points out, there are several cases: (1) The impression of the agent remains permanently in the effect after the agent has ceased to act, if the impression be¬comes part of the nature of the effect. For instance, if a stone is generated in Nature, it persists with its properties, as its hard¬ness and its heaviness. (2) Some things become partially attached to the nature of the subject and may persist for a long time; so habits, disposi¬tions, etc., in man. (3) Things of a more noble nature do not remain for an instant after the action of the agent has ceased; so light does not remain in a body when the source of the light is removed. To these cases we might add a fourth, allied to (2): (4) Impressions such as the violent motion given to a stone by the thrower, the heat induced in a body by being in the neighborhood of a fire, and the potency of the semen; these impressions persist for some time after the action of the original agent has ceased; the duration of their persistence depends upon the surrounding medium and its ability to conserve the original action; the subject itself has no firm grip on such impressions. Transient impressions which come under case (4) must not be confused with permanent impressions belonging to case (1). Thus, in (1), if a heavy body is generated, the body retains its heaviness indefinitely after the generator has ceased its opera¬tion, because the form of heaviness has been imprinted on the body and has entered into its nature. Accordingly, if at any subsequent time an obstacle is removed, the body will move spontaneously downwards towards its natural place. Similarly for light bodies which move upwards. On the other hand, in (4), if a body is moved violently, the violent motion is not given to the body as its form or nature, and consequently the body does not of itself retain the violent motion; the motion which the archer imparts to the arrow persists for a certain time and then fails. The violence received from man never becomes part of the nature of the arrow as does an impression received by the creative operation of God; the violence is a transient thing given to the body in addition to its nature. Thus, St. Thomas, in his Commentary on the DE CAELO of Aristotle, discusses the question of natural and violent motion and is at pains to make this distinction between them. It must not be thought, he remarks, that the mover producing the violent motion of the stone impresses on the stone motive virtue by which it is moved, in the way in which the virtue of the generator impresses on the thing generated a form from which the natural movement of the latter results. If this were so, continues St. Thomas, the violent motion of the stone would be an intrinsic principle in the stone, which is contrary to the notion of violent motion. Further, it would follow that the stone, from this very fact that it is moved locally by violence, is altered, which is against common sense. In general, writes St. Thomas in another place, “that which creatures receive from God is their nature, while that which natural things receive from man in addition to their nature is somewhat violent.” And again: “Art takes its matter from nature, and nature receives its matter from God through crea¬tion. Now the products of art are preserved in being by virtue of the products of nature; for instance a house by the solidity of the stones. . . .” In figurative terms we may say that art is God's grandchild. It is clear then that the impressions made by art on nature are not permanent, but are inherently subject to attenuation and disappearance; the arrow falls, the house perishes. While the impressions of art do persist, they are preserved by natural means invoked for the purpose, as by the archer and the architect. Let us now consider how the violent motion of the arrow is continued for some time after it has left the archer.
How is Continued Violent Motion Possible?
The Philosopher [Aristotle] gave much thought to this subject. “If everything that is in motion, with the exception of things that move themselves [i. e., animals], is moved by something else, how is it that some things, e.g., things thrown, continue to be in motion when their movent is no longer in contact with them?” he asks.
[1]
Some have suggested, continues the Stagirite, that the solution to the problem lies in a process of "mutual replacement" (
antiperistasis)
: the thrower at the same time as he throws the thing thrown, also imparts motion to the air, and the air in motion in turn imparts further motion to the thing thrown.
[2] In general, A pushes B, B pushes C, C pushes D, and so on, and even, in a circular fashion, Z pushes A; hence the motion is continued, like the trucks in a railway train or the endless motion of a revolving belt. But it is manifest, says the Philosopher, that in such a case all the members, whatever the exact sequence may be, would have to be in motion simultaneously, or at rest simultaneously, and hence when the original movent ceases to move the series all movement would instantly cease. The process of
antiperistasis on this ground alone, not to mention other defects, fails therefore to explain the continued motion of the single thrown body after the original act of throwing has ceased. Hence, observes Aristotle, we must look elsewhere for the explanation of the thrown body.
[3]
It is not the continued
movement of the medium which explains the movement of the projectile; this only pushes back the problem one step, since we still have to explain the continued movement of the medium. The continued local movement of the medium must be ruled out as the source of the projectile's continued motion: yet the source must lie with the medium in some way, since the medium is the only possible source of the projectile's continued motion after it has left the thrower, so the Philosopher writes.
[4]
Thereafter while we must accept this explanation
[antiperistasis] to the extent of saying that the original movent gives the power of being a movent either to air or to water or to something else of the kind, naturally adapted for imparting and undergoing motion, we must say further that this thing does not cease simultaneously to impart motion and to undergo motion: it ceases to be in motion at the moment when the movent ceases to move it, but it still remains a movent, and so it causes something else consecutive with it to be in motion, and of this again the same may be said. The motion begins to cease when the motive force produced in one number of the consecutive series is at each stage less than that possessed by the preceding member, and it finally ceases when one member no longer causes the next member to be a movent but only causes it to be in motion. The motion of these last two - of the one as movent and of the other as moved - must cease simultaneously, and with this the whole motion ceases.
[5]
In another place the Philosopher sums up the theory of the continuance of violent motion in a succinct manner when he says: “the force transmits the movement, to the body by first, as it were, impregnating the air. . . . If the air were not endowed with this function, constrained movement would be impossible.”
[6]
The original violence initiates the movement and gives to the circumambient medium the power of continuing it; however this is a transient power, and diminishes and finally fails, whereupon the violent movement ceases and the projectile falls.
It would appear that we must recognize in the medium not only a propulsive but also a resistive agency; the medium offers different resistance to the body's movement according as the medium is more or less easily divided by the body.
[7] Thus, we can throw a stone more readily in air than under water. We shall further consider this twofold action of the medium later in connection with natural motion.
St. Thomas fully agrees with the foregoing doctrine of Aristotle. In the section of this
Commentary on the DE CAELO to which we have previously referred,
[8] St. Thomas lays down, that in the violent movement of a stone the mover impresses motion only while it is in contact with the stone. Nevertheless, because air is both subtle and light it is susceptible to impressions. Consequently, when the violence of the mover desists, the air in contact with the stone continues to propel the stone, and gives also propulsive power to the conjoined air, which in its turn propels the stone, and so on. Consequently the first violence endures in the stone to all appearance, but really the stone continues to move because of the successive impressions of the air. Hence, if there were no such bodies as air, there would be no violent motion -
si enim non esset tale corpus quale est aer, non esset motus violentus.
Aristotle and St. Thomas are unanimous that movement in a void, if such could exist, would be impossible.
[9] In a void there would be no motivating medium to cause motion; nor would there be any determinate direction for movement, so that there could be no directed motion, which is absurd.
[10] A stone could not be thrown from the hand nor an arrow shot from the bow in a void, if there were such.
This principle is the antithesis of the doctrines of original impetus (of which more in a later place) advanced by Buridan, Descartes, Newton, etc. According to the impetus doctrine, motion in a void is not only possible but is the most free of all motions and persists indefinitely; the function of the medium for the impetus theory is merely to retard motion.
The Principal Agent and its Instruments.
St. Thomas embarks on an interesting discussion of motion in the
De Potentia.[11] He compares the continued movement of the arrow with the retention by the semen of the force originally imparted to it by the soul. This comparison has sometimes been taken to mean that St. Thomas subscribed to a theory of impetus for moving bodies.
[12] In truth, however, it cannot be thus interpreted. Let us consider St. Thomas' words:
An instrument is understood to be moved by the principal agent so long as it retains the power communicated to it by the principal agent; thus the arrow is moved by the archer as long as it retains the force wherewith it was shot by him. Thus in heavy and light things, that which is generated is moved by the generator as long as it retains the form transmitted thereby: so that the semen also is understood to be moved by the soul of the begetter, as long as it retains the force communicated by that soul, although it is in body separated from it. And the mover and the thing moved must be together at the commencement of but not throughout the whole movement, as is evident in the case of projectiles.
It will be evident in the first place that St. Thomas' comparison here between the semen and the projectile is somewhat general, and is not to be taken in an unduly literal manner. The force impressed on the semen is more firmly attached to its nature than is the violent motion of an arrow. Furthermore, St. Thomas holds that the form of heavy and light bodies is not the
cause of natural local motion, but is its
principle, as he relates in the
Contra Gentiles:[13]the form determines the place to which the body has a tendency, the actual movement to that place must have another and external cause, namely, the impulsion of the medium. Thirdly, even the continued force of the semen is dependent upon a suitable medium to preserve that force,
[14] as indeed is manifestly the case with the preservation of any living thing.
In this discussion in the De Potentia St. Thomas does not refer to the action of the surrounding medium because here he is taking that action for granted. With the semen the retention of the force given to it by the soul of the begetter depends on the proper medium to conserve and apply that force. So with the arrow: the retention of the force given to it by the archer requires the participation of the medium, to preserve in itself the impression for as long as is proper, and to guide the arrow to the place determined by the original act of the archer.
St. Thomas is primarily concerned in this discussion with the fact that a body receives its power from the original agent, and retains it for a time after it leaves that agent; the arrow does not take off on its own account, nor does the semen acquire its force except from the begetter. The medium cannot originate the movement, only the initial act can accomplish this; but the force or impulse once given by the principal agent, the medium's function is to take up the subordinate task of carrying out the movement; so the movement persists after the body has separated from the principal agent. Thus, the captain directs and the sergeant sees that the direction is carried through. The whole movement depends on the initial act of the principal agent and is executed by the instruments of that agent under the agent's direction. Failure to achieve the end laid down by the principal agent is due to the defectibility of the instruments.
On the primacy of the principal agent St. Thomas writes: “An effect is ascribed more especially to the direction of the first mover towards the end than to the instruments which receive that direction,"
[15] Thus he can continue: "The arrow receives its direction to a fixed end through the impulse
[ex impulsione] of the archer, so, too, natural bodies receive an inclination to their natural ends from their natural movers [the heavens], from whom they derive their forms, powers and movements," without in any way implying a doctrine of impetus. In the impetus doctrine no instrumental agent is required to continue the original action; in St. Thomas' doctrine, a continuous hierarchy of movers is required.
Thus in no way in his doctrine of local motion does St. Thomas weaken the force of the principle that whatever is moved is moved by another.
The Attenuation of Violent Motion.
Why does the arrow finally fall? Why does its flight not continue indefinitely under the influence of the propelling air when once started by the archer? In considering this question we should see it in its more general content: always we perceive that the nearer a thing is to its cause the more powerful is the effect of that cause. Thus the nearer a body is to a fire the hotter it is: the heat of the fire is actual and it moves the neighboring body from potency to act, so that heat becomes actual in the body. The nearer the body to the fire the greater is this effect, and consequently the hotter the body becomes.
[16] So, a man who knows arithmetic teaches it to another, and the more conscientiously the pupil applies himself, the more does he learn.
Duhem cites an illuminating passage from al Bitrogi, the disciple of ibn Rushd, in which the attenuation of violent motion is compared with the general inward radial attenuation of motion in the cosmos, al Bitrogi writes:
[17]
[the stone and the arrow] continue to move, but by means of a virtue which remains applied to the stone or to the arrow after the projector has launched it; the more the arrow is separated from its motor, the more feeble the virtue becomes. As this virtue is consumed when the arrow falls, so the virtue that the Supreme Mover confers on the inferior spheres diminishes continually until it comes to the Earth which remains naturally immobile.
An influence radiating from a central point through a hierarchy of agents is attenuated and divided and diversified the farther removed it is from the center.
[18] This is true whether we consider a state or a transition, whether the spreading ripples caused by dropping a pebble into a pond, or the cosmos as a whole proceeding from God.
The general principle illuminates such diverse things as the imperfection and contingency of the sub-lunary world and the inferiority of man's intellectual powers to the angel's. The eventual fall of the arrow; the crumbling of the old house; the impotency of seeds kept too long; the gradual cooling of hot bodies when the fire is removed; each of these processes of decay may be hastened or retarded in its own way according to the surroundings; but its ultimate extinction is as certain as the imperfection of terrestrial affairs compared with celestial.
[1] Physic. 266 b 27-30 (Oxford ed.).
[2] Physic. 215 a 15; 266 b 30 f.; 267 a 16 f.; etc. Ross' Commentary on the
Physics of Aristotle may profitably be consulted on
antiperistasis and related matters.
[3] It is remarkable that so well-informed an historian as Pierre Duhem should have been mistaken about the Aristotelian doctrine on this matter. He attributes, quite wrongly, the absurd theory that the moving air impels the projectile, to Aristotle. In fact, as we have seen, Aristotle is at pains to show how untenable such a theory must be (cf.
Leonardo, t. 3,
préf., p. vi, etc.).
[5] It is instructive to compare this process described by Aristotle, of combined motion and power of giving motion, with wave progression: e. g., the spreading ripples produced on the surface of a pond when a pebble is thrown in. We shall have more to say on this matter hereafter.
[6] De Caelo 301 b 25-29.
[7] Physic. 215 a 30, etc.
[8] III de Cael. et Mund., lect. 7.
[9] Physic. 215 a 18; a 23.
[10] Let us remark here that the so-called "vacuum" obtained by pumping the air out of a vessel is not to be regarded as a void, but rather as a medium of rare lightness and subtlety in which both natural and violent motions proceed with facility under the influence of the aethereal medium. A suggestive similitude will be found in the theory of "wave mechanics," a subject we shall discuss later.
[11] De Pot., q. 3,
a II, ad 5.
[12] So, apparently, Garrigou-Lagrange:
God: His Existence and His Nature, I,
274 f. Dominic Soto, O. P. (1494-1560),
the celebrated Spanish philosopher and theologian, invoked this discussion of St. Thomas' to support, it is said, an impetus theory of motion. Cf. Duhem,
Leon. t. 3, p. 286 f.
[13] III Cont. Gent., c. 23.
[14] An interesting case may be found in the modern practice of artificial insemination in animals which often requires the prolongation of the force of the semen beyond its ordinary span. This is accomplished by providing a suitable medium at a favorable temperature.
[15] III Cont. Gent., c. 24: "How even things devoid of knowledge seek the good."
[16] On the doctrine of heat see, for instance, the last paragraph of
III Cont. Gent., c. 69 (cf. Aristotle,
Physic. 255 a 23). It will be evident that this doctrine of heat differs fundamentally from the theory of heat held in modern "Kantian" physical science.
[17] Duhem,
Leon., t. 2, p. 191.
[18] III Cont. Gent., c. 64;
Summa Theol., I, q. 89, a. 1, etc.
33 De Caelo 308 a 3; 310 b 25, etc
To be continued ....
Frits Albers’ critique of Gavin Ardley’s article,
“The Physics of Local Motion”
… My main objection to the alleged interpretation and application of the Aristotelian principles put forward by Ardley is, that they arbitrarily transfer the whole debate from ‘motion’ to ‘power to move’, and so become inconsistent with REAL facts.
I accept with St. Thomas the truth of the two universal principles that
(1) “whatever is moved is moved by another”, and
(2) “motion is recognized as a transition from a state of potentiality to a state of actuality”,
both quoted by Ardley in his “Physics of Local Motion”. They do neither include nor do they prepare us for what is to be brought into the debate: the altogether alien matter of the ‘transfer of power’ to actualise by another agent what had been actualised by its proper agent. I cannot stress enough that ‘power to actualise’ and ‘power to transfer actualisation’ are two totally different and unrelated matters. For either
(a) the original agent, although perfectly fitted to actualize a certain potential, may be totally unsuited to actualize the totally different potential of transferring the actualisation, or
(b) the new agent may be totally unsuited to be actualised for the execution of this original actualisation even regardless of the ludicrous situation when we do not know HOW, or by WHOM or by WHAT the transfer of power has been actualised.
Needless to say, this ‘transfer’ is not treated by Ardley in the sense that it is not even remotely explained. It remains a totally mysterious thing and breaks down on various occasions. Simply pointing to ‘air’ as the new agent is neither good physics nor good metaphysics.
Consider a 12-ton railway carriage, shunted by an engine and now quietly rolling along at a brisk jogger’s pace, unable to be stopped in its tracks by 10 able-bodied men. How can this engine, perfectly suited to actualise the carriage’s potential to motion, now do a totally different thing: cease to be the perfect actualising agent, and transfer the power to actualise that same potential to air? Just claiming that this must happen in the non-apparent need of another power or of another explanation is not serious metaphysics and results in unreal physics. No one can seriously entertain the thought.
(a) that air has now taken over the role of the engine and actually has received the power to move the carriage, and
(b) that air got this power from the engine.
The fact that marbles, once set in motion, roll perfectly on a horizontal plane in a man-made vacuum (airless tube) shows that air does not come into it. Yet the moving carriage and the moving marbles perfectly fulfil the two universal truths quoted above: they were moved by another and their movement is a case in which a potential they possessed has been activated.
The Ardley doctrine of transfer breaks down in the circular motion of a flywheel (grindstone). Here even ‘aether’ (in the absence of ‘air’ as a medium) would find it impossible to move the grindstone to the right at the top and to the left at the bottom, up on the left and down on the right. In fact it is impossible to let a ‘transfer-agent’ cater for the variations in speed (motion!) along the radial of the wheel. Yet here again, the motion of the wheel is in perfect accord with (1) and (2) above.
The fact is that, wherever we observe the actualisation of a potential into act, we see the actualisation being performed by an agent perfectly suited for the realisation of the potential, i.e. to make the potential actual, real. The flying stone, the bowled cricket ball, the fired bullet, the shunted carriage, the circling satellite, the turning flywheel all received the actualization of THEIR potential by THEIR most appropriate agent. The bowler does not move a railway carriage; the flying stone does not receive the power to go into orbit; only in tornadoes do we see air give powerful motion to flying objects. They are all examples of the one universal rule: the immediacy between an act and the actualisation of a potential appropriate to that act and appropriate to the potential.
And here we come across the solution that escaped Ardley and …. whoever.
Even in ‘local motion’, the question is not primarily one of motion, but of the much broader and far more primary (or fundamental) question expressed in (2) above: the actualisation of a potential. As shown by innumerable examples in nature, there is always an ‘immediacy’ between the already existing (actual) agent (perfectly fitted to perform the actualisation) and the potency that is being actualised. Circling satellites and rolling marbles show that ‘air’ does not come into this immediacy when the motion ‘in vacuum’ is considered; and the enormously complex actualisation of the motion of a freely rotating flywheel (up to the 5th power) eliminates ‘aether’ from the actualisation of this very specific potential, even assuming that such ‘transfer’ was feasible. In the absence of a ‘mediate’ agent, the freely rotating flywheel brings us back to the ‘immediacy’ between “act and potency” in motion as it is in ALL actualisation of a potential. If this immediacy exists between the ‘agent’ and the ‘motion’ of a turning flywheel as the only required bond expressed in (2) above, why not in ALL motion where, as examples of (2) above, there can only exist an immediacy between the perfectly fitted agent and the perfectly adapted result.
Ardley does not explain the mechanics, the steps, the HOW of the irrevocable break he postulates as occurring in the immediacy that exists between “act and potency” in motion, between the shunting engine and the carriage, once the carriage leaves the engine. This break in immediacy between act and potency is never postulated anywhere else in philosophy.
Neither does he explain HOW this ‘immediacy’ is now transferred to a most unsuitable agent, air, just because it is lying around. “Here, you will do!” But in the case of the rolling carriage we have the additional anomaly that the air is supposed to have received power to ‘move’ the carriage, but has no effect on the turning wheels (being examples of rotating flywheels) by which this movement becomes possible. The engine as the first and perfectly fitted actualiser of the whole movement saw its actualisation suddenly interrupted, broken off, and transferred to a most unsuitable ‘agent’ which did not even possess any of that potential even to have it actualised.
Impetus?
Not in the Newtonian sense of giving to something the property to keep itself in motion in the absence of the fundamental requisite of the Aristotelian philosophy: hylemorphism. In true Aristotelian metaphysics the realisation of the potential remains under the immediacy of the primary act for the duration of the actualisation without giving to the object “a second nature it did not have before”. And so the moving object remains moved “by another” even if not moved by air. ….
In conclusion I may quote two great Saints.
First St.
Thomas:
“The fact that the phenomena can be explained this way (Ardley) is no proof of the truth of these theories. For possibly the same phenomena might be explained in a wholly different way as yet unknown to men”.
To avoid being included in this wise warning, I have abstained from using physical principles as Ardley did, (air) and highlighted what the requirements are of the fundamental doctrine of “act and potency”. If one veers away from that, it must be done on sound metaphysical principles. To advocate a break in the essential unity between act and potency is bad metaphysics. It stinks of Manichaeism in which people can consider themselves excused from the immediacy between their acts and the results of their acts, and transfer the results to an agency outside themselves.
And then St. Bellarmine:
“In this I may myself be considered not bound by St. Thomas”, if St. Thomas advocates this “break” and this wholly unnecessary and totally inadequate “transfer”. …
[Ardley] starts with two metaphysical principles,
(1) whatever is moved is moved by another, and
(2) motion is recognised as a transition from a state of potentiality to a state of actuality.
In other words, he wishes to open up before his readers a metaphysical dissertation. And specifically, he wishes to develop his whole thesis within the context of ‘hylemorphism’, the doctrine of the transfer from potentiality to actuality. But not fully understanding either the universality of metaphysical principles in general or specifically the hylemorphistic principles in particular, he brings ‘air’, a physical entity, not only into his argument, but in to the fundamentals of his arguments, and with that the whole thing collapses; from then on it is neither physics nor metaphysics, but a “dangerous mixture” which is impossible to gel. Needless to say, the tranfser to ‘air’ from whatever went before to whatever role ‘air;’ is now supposed to do becomes inexplicable (mere verbiage) as from now on his whole argument is no longer metaphysics, but neither has it come down to true physics, bur results in a degeneration of both.
… I developed my whole argument within the context where Ardley fell away …: within the context of hylemorphism on the fundamentals of Aristotelian metaphysics. As a brief recapitualtion of what I said I highlight the following:
ALL actualisation from potentia to act takes place IN the potentia. The form an artist gives is IN the marble, the UN-formed ‘matter’. Thus, if motion is a true actualistion from ‘potentia’ to ‘act’, then, as long as the motion lasts, the actualisation takes place where the potentia is: IN the moving ball, the rolling railway carriage, the encircling satellite. THAT is the immediacy between act and potentia, not the physical ‘nearness’ of the cause, and THERE it is where it takes place. The cause remains IN the actualisation of the potentia. And the moving carriage clearly shows that actualisation is still taking place.
In other words: THE AIR COMES TOO LATE! There is no room for it! The actualisation the engine gave to the potentia of the carriage is already taking place precisely where the potentia is: IN the moving body even before they separated, and it is obvious that it is THERE where this actualisation continues after separation until the carriage stops. And since it is equally obvious that, as long as this actualisation continues and the cause of it is continually present (even if not ‘near’: NO physics!), the moving object is truly moved by another for as long as the movement lasts, since ALL actualisation clearly shows that the cause of it is present for ads long as the actualisation endures. Depending on whether the carriage has to be shunted for a mile of for a few hundred yards, the engine will give the precise actualisation to the potentia for the required result.
For as long as ‘Moses’ remains ‘in the marble’, the actualisation of this form endures, even if the artist is long since dead. As the ‘cause’ of this actualisation he is still present in the actualisation. And depending on the size of the statue, the artist will give ‘form’ to the ‘marble’ for the required effect. The cause puts an indelible stamp on his, her, its actualisation of a specific potential. That’s how specific causes are immediately recognised: a bowled cricket ball, a moving carriage, a long-forgotten painting. ….
And that is why St. Paul could write to the Romans, and over their heads to all of us,
“The anger of God is being revealed from Heaven against all impiety and depravity of men who keep Truth imprisoned in their wickedness. For what can be known about God is perfectly plain. Ever since God created the world, His everlasting Power and Deity – however invisible – have been there for the mind to see in the things He has made. That is why such people are without excuse: they knew God and yet refused to honour Him as God, or to thank Him. Instead, they made nonsense out of logic and their empty minds were darkened. The more they called themselves ‘philosophers’, the more stupid they grew …” [Rom. 1:18-22].
