Gravity and Aristotle's Aether

Planet Earth from the probe Cassini viewed from the far side of Saturn [NASA/JPL]

When Sir Isaac Newton propounded his formula for the universal law of gravitation, he did not make the mistake of confusing its calculation with its causation.[2] Criticised for arguing to the existence of some external and undetectable cause, he responded that it was enough that phenomena implied attraction but he had never “[sought to assign] a cause to this power”.[3]

For all the sophistication of its knowledge, modern science has yet to discover gravity’s cause. Treating gravity as a force of attraction between the relevant bodies satisfies the demands of the physical principles involved. The primal problem with the thesis of attraction, however, is that there is nothing in a body of matter qua matter that demands that it should attract another. There is, moreover, no medium of transmission whereby the immense centripetal forces involved could be conveyed from one celestial body to another body. Common sense would indicate that gravity’s cause is not to be found within celestial bodies but from some force outside them—not something intrinsic but extrinsic—but the business remains a mystery.

There have been many attempts to explain gravity as a species of extrinsic force. They have foundered over difficulties about the nature of the force and about the mode of its operation. In the late 1740s Georges Louis Le Sage, for example, proposed a mechanical explanation arguing that the force was constituted by particles of great rarefaction.[4] But science revealed that material bodies are largely porous, ‘mostly empty space’. His hypothetical particles would be expected, then, to penetrate, rather than to bear upon, the surface of celestial bodies.

The philosopher Immanuel Kant raised a more fundamental objection. Le Sage’s particles must, he argued, have a ‘non-zero’ radius. This implied the existence of some sort of binding force to hold these particles together. Now, that binding force could not be explained by the gravitational particles themselves. Hence there had to be some additional force binding these, and so on, ad infinitum. This objection, addressing as it did the influence which provides extension and parts to a material substance, the metaphysical category quantity, demonstrated that one could not hope to discover an extrinsic cause of gravity and ignore the force that binds atomic and molecular structure. It also showed that a substance that could produce such a force must be superior to any of ordinary matter.

Modern science is concerned with things observable, with phenomena. Its theories, its determinations, its prognostications, are all grounded in mensurable data. It notes effects, it looks for causes to explain them : and because its modus is almost exclusively inductive the causes at which it arrives are not necessarily the true causes or, if true, are not necessarily ultimate causes. For certitude in induction depends upon the discovery of a sufficiency of effects to exclude error about the cause. An explanation may ‘save the appearances’, as St Thomas remarked about Ptolemaic astronomy, and not exclude the possibility of another theory providing a better.[5]

Modern science has another limitation. It is informed—and has been for some 350 years—by a defective philosophy manifest in two poles of thought, materialism and subjectivism. The one contends that if something cannot be detected experimentally, it does not exist ; the other that only that is true which the individual, or the majority, asserts to be true. These defects reflect the mentality of worldly thinkers who have long since turned their backs on any philosophy which addresses the part of reality which is not material. The result is that experimental science frequently fails to reach sound conclusions. Has there ever in the history of mankind been an age to compare with the present in knowledge, and in lack of wisdom ? T. S. Eliot put it succinctly :

The modern world is apt to dismiss the thinking of Aristotle and St Thomas Aquinas in the realm of nature because it can show their cosmology to be defective. But their cosmology was not so much defective as limited. Their analyses, grounded in reality rather than the limited vision of modern philosophies, more than compensate for shortcomings in knowledge. We propose to set out the principles they expounded concerning the behaviour of the heavens and gravity—though neither recognised this latter as the entity whose laws were codified by Newton—and to revisit their insistence on the existence in the natural world of an element which modern science refuses to acknowledge.

We will begin with a self-evident principle: nothing, i.e., non-being, does not exist. Its corollary is this : every material thing is surrounded by other material being however intangible. We may accept this readily enough in respect of the bodies we encounter in daily experience. Even if we cannot discern, we can imagine the proximity (taken literally here as ‘the next-ness’) of other material being to the very least of bodies : but what of celestial bodies in outer space ? What of the atoms and molecules of which material bodies are constituted but surrounded, so science tells us, by ‘empty space’ ? Neither of these ‘spaces’ can be empty : principle prevents it.

Modern science maintains that notwithstanding that light is a material reality it does not need a material medium in which to travel. How can this be ? If light encountered a somehow existing ‘nothing’, would not this ‘nothing’ be an impenetrable barrier to its passage[7] ? Einstein tells us that the relationship between energy and the mass of a body is a function of the speed of light. But what on earth has that ethereal, if powerful, reality, light, to do with the relationship between those two ? The answers to these questions lie in the acknowledgement of the existence—and the remarkable characteristics—of an element of the material universe whose reality was exposed by Aristotle. He called it ‘the heavenly body’, or ‘first body’, or aether ; later thinkers have referred to it, perhaps dismissively, as ‘the quintessence’[8] .

Here are the relevant teachings of Aristotle in natural philosophy and cosmology with the additions of St Thomas, his greatest commentator. We refer to the two hereafter collectively as ‘the Philosophers’. For the purposes of this exercise the reader is asked to accept, for the moment, the limitations in their knowledge. The references for the most part are from St Thomas’s commentaries.

iii. The passive principle of the motion of the heavens is that body’s nature according to which it is apt to be moved with such a motion, but—

iv. There are four species of motion—generation, increase, alteration and local motion [In IV Physics L23, 631]—but the first, the more simple, and regular of motions is this last, local motion. [In VIII Physics L 14, 1094-5] All local motion is either straight (rectilinear) or circular, or some combination of these two. [In VIII Physics L 16, 1105] Straight motion is imperfect because it involves contraries ; for it must cease when it reaches its term, or return by reflex motion to its beginning. [In VIII Physics L 16, 1106] In contrast, circular motion—

v. The universe is spherical and, since all motion is founded upon something immobile [In I De Caelo, L iii, 36], its motion must be considered in relation to its immobile centre. Hence, reflecting their respective relations to the universe’s centre, there can be only three simple natural motions—one from the centre, one towards the centre, and a third around the centre. [In I De Caelo, L iii, 36]

vii. A simple body is one that has a principle of natural motion. There are four simple elements : earth, air, fire and water. Fire and air have a principle of straight motion away from the centre (of the universe), as earth and water have a principle of motion towards its centre. Circular motion is perfect motion ; it has no contrary. Such motion, simple and distinct from straight motion, must be proper to some natural simple body other than these four. [In I De Caelo, L iii, 36]

viii. This fifth element, as befits a substance with perfect movement, is perfect[10] . It is higher and nobler than the four simple elements. It is incapable of being generated or corrupted ; incapable of expulsion from its proper place by violence ; it has no lightness or heaviness ; it has no contrary ; it is prior to, and contains, all other bodies.

Moreover, as it contains all other bodies, this element is to them as form to matter and as act to potency. [In I De Caelo, L iv, 50]

xi. This, the heavenly body which St Thomas refers to as ‘first altering body’, is universal in the heavens. Following Plato, Aristotle and St Thomas, we call it aether.

To this list we must add the Philosophers’ insistence on the principle that all motion in the universe is founded on something immobile.

III

i. The earth is a globe turning on its axis once each day. It circles the Sun each year, its rotational axis inclined some 23 degrees to the perpendicular of the plane of its orbital axis. The moon is a satellite circling the earth every 27.3 days, though taken with respect to the earth’s motion around the sun it takes 29.5 days for it to return to the same place in the sky. These heavenly bodies and all the stars and planets that people the sky are immersed in an apparently empty sea of space. Sun, moon and stars do not rotate around the earth each day. Their apparent daily circuit is a function of the planet’s rotation. The elements of which material bodies are comprised are not four but (at last count) 118.[14]

ii. Let us recall the very first words of Divine revelation: In the beginning God created the heavens and the earth… Notice that the sacred author first says that God created the heavens. This accords with philosophical principle. No material thing can come into being, can exist, save in a pre-existing material setting. The earth and its various component parts—the stars, the sun, the celestial bodies, and the elements of which these are comprised—none could have been created in vacuo ; for nothing (a void) does not exist. What, then, are we to understand by the expression ‘the heavens’ ? (The Latin Vulgate, incidentally, reads caelum, i.e., the singular, ‘heaven’) It is not unreasonable to conclude that ‘the heavens’ in the text signifies not the sun, moon, planets, stars and other celestial bodies, but aether ‘the heavenly body’ ; and ‘the earth’ signifies not just our own planet but all celestial bodies, indeed, all ordinary, or common, material being.

When the Philosophers say that aether is ‘first body’ they mean exactly that ; first in the order of reality, first in the order of time. The apparently empty void of space is replete with it. But let it be understood that ‘replete with’ is not convertible with ‘filled’, as if aether was a fluid poured into an empty vessel. Aether, not void, is first in the order of reality : where there is no other material being, there is aether. While imagination inclines us to view a void as reality’s ‘default setting’ (to adopt modern computer jargon), intellect insists it is the first body, aether. Aether is the universe, the matrix in which every celestial body exists ; the universe is aether. St Thomas appears to acknowledge this in his second lecture on the first book of the De Caelo.[15]

iii. When it is said that aether is an element of the natural world this is not to be understood in the sense of ‘a component’.

Now what is said about aether’s involvement in the operations of the celestial bodies is, in the view of this commentator, no less true of the substances of which they are comprised. These do not subsist, do not come into existence, save in aether as their proper matrix. Much as the sea is the medium and essential condition in which fish and other creatures exist, aether is the medium and essential condition of the existence and coming into existence (the be and become) of all material things. In the author’s view aether cooperates with first metaphysical accident quantity in binding the atomic and molecular structure of each bodily substance.

iv. The Philosophers conceived of the celestial bodies as embedded in concentric spheres with their motions determined by this heavenly body. They were aware of the reality of gravity as ‘heaviness’ and that this involved a force or tendency downwards. They understood, too, that the earth was spherical, but held it to be fixed and its centre the centre of the universe. If certain bodies had a downward motion it was because that was part of their nature.

Modern science notes a number of effects universal among celestial bodies—spherical formation ; circular movement ; gravity. We know that the moon rotates about the earth ; that the planet circles the sun ; that the sun and stars circle in our own galaxy, the Milky Way, and that stars circle in other galaxies.[17] If science has confirmed anything it is that circular motion is as characteristic of the bodies that people the universe as it is uncharacteristic of the mundane. Now this universal effect as those of spherical form and gravity must have a proportionate cause.

v. Many realities in nature are not scientifically detectable. Science cannot, for instance, detect experimentally the cause of life in a living being. This reality has no weight, no colour, no appearances, nothing which can be measured. One can only conclude to its existence from effects. Yet it is the essential element of the living thing.[18] Notwithstanding its besotted-ness with materialism, science cannot, accordingly, object to some reality simply because it is unable to discern the presence of, or measure, its physical characteristics.

Now, cause and effect are always proportionate. The more particular an effect, the more particular its cause ; the more universal an effect the more universal its cause. If the thesis proposed here be accepted, it is clear that the only substance as universal as the effects of gravity, spherical form, and circular movement is aether. As a working hypothesis, then, let us assume that aether, the sea in which according to our thesis all celestial bodies subsist, is the cause of these effects.

vi. Let us recall what the Philosophers have to say of philosophical principle and the attributes they ascribe to this element, and weigh these against the realities science cannot explain.

The Philosophers’ contention that the immobile thing on which the mobility of the universe was founded was the physical centre of what they perceived to be its sphere is now shown to be problematic.[19] In perceiving the heavens (i.e., aether) as in motion the Philosophers were, of course, misled by the limitedness of their knowledge derived from the rotation of the planet on its axis. In the Michelson-Morley experiment (1887), science demonstrated that aether is undetectable.[20] While it is certain that aether moves per accidens, for it adapts to the movement of all other bodies, per se it would seem to be immobile. Indeed, careful reflection on the curious nature of this substance indicates that aether is immobile with respect to every element of common material being. Hence, even with respect to heavenly bodies moving at great speed in opposition to each other, the aether in which each subsists is immobile.[21] In summary we contend that aether is the immobile ‘something’ on which the motion of the heavenly bodies is founded and, to this extent, we would depart from the Philosophers’ teaching on aether’s proper motion and argue, instead, that circular movement is the proper effect aether induces in these bodies.

vii. In line with our thesis, aether is the principle of acting, the active principle, of heavenly motion but as instrument, not as principal. For the principal active principle is, as the Philosophers teach, an intellectual substance. The passive principle of the motion of the celestial bodies is embodied in their nature as comprised of the elements of common material being. Consistent with this is St Thomas’s assessment that, since it contains all other bodies, aether the heavenly body is to them as form is to matter, as act is to potency, i.e., is their determinant. [In I De Caelo, L iv, 50]

Had the Philosophers known of the discoveries of modern cosmology and those of science concerning the elements and their periodic table they would have had no difficulty adapting their teaching to encompass 118, rather than four, elements, to maintain that the quintessential body to whose existence they had concluded was—

For the motion proper to each of the 118 elements, as to the almost infinite number of their compounds, is rectilinear motion, and—

This last requirement is satisfied, in our view, if rather than being aether’s proper motion, circular motion is its proper effect ‘according to nature’.

viii. Therefore the motion of each celestial body about its own axis, as of its movement about another, is governed by some body whose proper effect according to nature is the induction of circular motion in other bodies, a body different from, and superior to, those other bodies.

Gravity (as every other created reality) has four causes ; two are intrinsic to the effect (the material and the formal causes) and two extrinsic (the efficient and final causes). Its formal cause is the inclination of the parts of the globe whether actual or potential (i.e., above, or on, or within it) of which a celestial body is comprised towards its centre : the material cause is the globe and those parts. The final cause, taken as the ultimate end of the operation, is the ordering of the globe and its parts to the good of the whole. Taken as the immediate end it is its focus or centre. The efficient cause is the agent that produces the gravitational effect : it is duple, principal and instrumental. The principal efficient cause is an intellectual substance, the instrumental cause the means the principal uses.

Clearly the instrumental efficient cause of gravity cannot be the globe itself for the efficient cause is extrinsic to the effect, while the globe, the subject of gravity, is intrinsic. It is impossible, moreover, that the same can be both intrinsic and extrinsic causes under the same respect of the same effect.[24] Just as clearly the cause must be an agent as universal as is the effect.

ii. Aristotle remarks on the contrariety to be found in nature.[25] There should be no surprise, then, that the superiority of aether to bodies of ordinary matter involves contrariety. A body of ordinary matter acts from within for nature is an intrinsic principle providing determinatepowers, acts and ends to its subjects. In contrast, aether, as befits the container of all other bodies, acts from without. If pressed, aether offers no resistance ; it is wholly pervious to extrinsic influence.[26] Aether’s operations in respect of gravity are completely counter-intuitive.

Let us recall that the problem of celestial centripetal force (gravity) is that no medium has ever been detected or even suggested whereby the immense centrifugal forces dictated by the innate tendency of a celestial body to rectilinear motion could be overridden to compel it to circular motion. This is the reason gravity is treated as an innate force of attraction.

The problem of the medium can only be solved if it is understood that the contrariety in the way mundane and celestial circular motions occur corresponds to a fundamental difference in the natures of the relevant acting bodies. Do follows be[27] : difference in modus operandi reflects a difference in modus essendi. In bodies of ordinary matter centripetal force precedes circular motion ; centripetal force must be secured before circular movement can be achieved. Before a wheel can turn spokes must be in place ; before dancers can spin around a common axis hands must be interlocked. Though the two realities, centripetal force and circular motion, occur together in time, ontologically, i.e., in the order of reality, circular motion depends on centripetal force. The dynamic is from within to what is without.

In contrast to this, Aristotle teaches that the agent that produces circular motion among celestial bodies operates at the circumference of the circles of motion.[28] That is, in aether’s realm circular motion is initiated not at the centre but at the periphery. The dynamic is from without to what is within. Celestial circular motion does not depend on centripetal force : centripetal force (i.e., gravity) depends on circular motion. Moreover, it does not seem necessary that there be actual motion, the potency to aether’s influence is sufficient to generate gravitational force.

iii. It may be objected that the rotation of celestial bodies about an axis and the orbiting of satellites about a celestial body each occurs in one plane only whereas gravity operates in every possible plane about a celestial body’s centre. The answer seems to be that aether is not constrained by the limitations of bodies of ordinary matter. Whereas they operate particularly and in one plane, aether operates universally and in every plane. Thus does aether produce spherical form, for a sphere, which is the mark of gravity, is simply a compound of every possible circle about a centre. Aether’s proper effect is circular motion, perfect motion, and the form it produces is spherical form, perfect material form.

iv. The influence aether exercises falls within the metaphysical category action, an accident. To understand this we must understand what is meant by accident and by the reality to which it is the essential accompaniment, substance.

In metaphysics substance does not mean what the modern scientist means when he uses that term—a material body without regard to nature or quiddity.[29] A substance is something which exists in itself (be-in-self) not in another.[30] In contrast, an accident is something which exists not in itself but in another : it cannot exist save in some substance (be-in-other). The sky is a substance (or a mix of them) ; that it is lit is an accident. The sea is a substance ; that it is blue is an accident. A horse is a substance; that it is galloping is an accident. A dog is a substance ; that it is clothed in a coat is an accident. That this man, a substance, is standing under a tree is an accident.

The hardest thing for the modern mind (immersed, as it is, in materialism) to grasp is that substance is per se immaterial, i.e., something real yet not comprised of matter. The word ‘substance’ means ‘that which stands under’. Stands under what? Stands under the body’s physical characteristics, the first of which is quantity.

Every substance has nine accidents ; the first, quantity, provides physical extension and parts, i.e., provides the substance with a body.[31] The next accident, quality, makes the body be of what kind (qualis), giving it density, permeability or impermeability, hardness or softness, texture, colour, heat, and so on. The remaining accidents relation, when, where, action, passion, habitus and situs, determine it in every other possible fashion.

Substance is the reality that underlies the appearances on which science concentrates its energies yet confuses with quantity.

v. The sixth accident action[33] is, as the commentator quoted above [John of St Thomas] remarks, depends upon something extrinsic. Action entails the production by some agent of an effect in another, called a patient, with movement from one to the other.[34] There are different species of action. That which concerns us here is called ‘transitive’. An illustration : when something such as a spoon is placed in hot water the heat of the water (the agent) transfers into the spoon (the patient) ; action in the water is passion (seventh accident) in the spoon. Action is really distinct from the movement involved as a line is distinct from its curve. Action adds to motion the respect ‘from agent’. Passion, really distinct from the movement involved and adding to it the respect ‘unto patient’, is the reception of the effect. Action is an accident in the agent ; passion another, separate, accident in the patient.

Now much as hot water produces heat in a spoon, aether produces the passion of circular motion in a celestial body and the consequent centripetal force of gravity.

vi. The experiment of Henry Cavendish in 1797-8 involving two sets of lead spheres of differing masses, 1.6 lb and 348 lb each separately suspended some 9 inches apart and on alternate sides, established that there is an apparent force of attraction, albeit infinitesimal, even among mundane bodies. The smaller spheres moved towards the larger causing the supporting arm to rotate : the twisting of the suspending wire enabled the force to be measured against the wire’s torsion coefficient. Now if, as we assert, the force at work is not one of attraction between, but of extrinsic action by aether on, these bodies the experiment demonstrates that aether’s action is not confined to the heavens but is universal.

Examples of aether’s influence among the mundane may, perhaps, be seen in various earthly phenomena we ascribe to other causes. One is the soap bubble. When a pocket of air is captured by a soapy solution competing centripetal and centrifugal forces produce the evanescent miracle of spherical form. [Note, we are not using ‘centrifugal’ here in the sense of a force at right angles to the radius of the circle of motion but in the proper sense of ‘flying away from the centre’.[35] ] While the source of the centrifugal force is the trapped air, that of the centripetal force may be ascribed to the surface tension of the soapy water but only as instrument of a higher cause. Another instance may be that occurring in the manufacture of shot where small quantities of molten metal forced through a sieve fall into water and solidify as tiny spheres.

Cause and effect are always proportional. If spherical form in celestial bodies is the mark of aether’s influence, why are these earthly instances not also ?

vii. Let us recall the Philosophers’ teaching (III. iii above) that, while not a component, aether is an essential element of material being ; that “it is involved in the composition of the whole universe as being part of it.” The ‘space’ that, science tells us, makes up most of atomic and molecular structure of the elements and compounds of material bodies can, no more than that between celestial bodies, be ‘nothing somehow existing’. According to our thesis aether is involved intimately in the structure of each celestial body : it cooperates with first metaphysical accident quantity in binding atomic and molecular structure. Since, as the Philosophers teach, aether acts but cannot be acted on, the dilemma that confronted Le Sage’s thesis does not arise : aether’s extrinsic force bears not only on the surface but on the whole body.

This passion of inclination towards the centre of its mass of a celestial body resembles somewhat the passion of compression in a body submerged in the sea. Yet the analogy limps for, regardless of the depth and the intensity of its pressure, the creatures of the sea under nature’s edict retain their native forms.

i. But if gravity is produced by an efficient cause extrinsic to a celestial body, why does it give the appearance of a force of attraction, i.e., of something intrinsic ? If the matter (i.e., the subject) of gravity’s centripetal force is the globe of the celestial body and all its parts, the form (that which makes gravity be what it is) is the inclination towards its centre. But gravity’s strength or weakness, according to proven scientific principle, is a function of the mass of the heavenly body. In breach of metaphysical principle, then, gravity seems to be determined by its material rather than by its formal cause.

The native motion of every element of common matter, as of the bodies they comprise, is straight (rectilinear) motion, as Newton makes clear.

Velocity is speed + direction. A change in direction is a change in velocity and since circular motion involves constant change in direction, science regards a circling body as accelerating towards the centre of its motion.

The gravitational force ‘of attraction’ (Fg) between two bodies is calculated according to Newton’s celebrated formula as follows—
Fg = m₁ m₂ x G
r²
—where m₁ and m₂ are the masses of the relevant bodies, G is a fixed ratio called the gravitational constant, and r is the distance between the centres of mass. For the purposes of the present discussion we will not explore the subtleties elaborated by Einstein. Gravitational force depends radically, then, on what science calls mass. But what is mass?

Some say mass is constant proportion between force and acceleration, others constant proportion between weight and acceleration, a quantitative measure of an object’s resistance to its change of speed. While this force varies from place to place, a body’s mass remains unchanged—pace Einstein’s theories. Another view has it that mass depends on the number of atoms a body contains. This is problematic because atoms are not uniform across the elements as the periodic table shows. A further view says mass is proportional to the volume a body occupies.[39] Mass is clearly not volume for volume is variable under the influence of pressure and temperature. It is not weight for weight is an effect of gravity and varies with altitude, i.e., distance from the centre of the earth (or other celestial body).

Perhaps the most objective assessment, at least for the purposes of Newton’s Laws, is that it is a measure of the force necessary to deflect a body from the straight motion natural to it, in other words, a measure of its inertia. While the definition of each of these categories seems constrained by another in a bemusing circularity, it should be observed that science now expresses, in the unit the ‘Newton’, a measure of a body’s lineal inertia, the force necessary to cause it to accelerate at a given rate.[40]

iv. Aether operates, according to our thesis, universally and uniformly (via its proper accident of action) in and about each celestial body to produce in it the passion of circular motion. In the body it produces rotation on one of the infinite number of possible axes about its centre or focus and thereby generates internal centripetal force, gravity. The larger the body the greater the gravitational force generated and, it would seem, the more perfectly the body approaches spherical form. The inclination to the centre or focus, taken ontologically, is the formal principle of rotation of the celestial body, both actual and potential. But no celestial body exists alone in the aethereal sea. About the body, then, aether produces the passion of circular motion relative to each neighbouring body with an intensity that reduces in proportion to the square of the distance between them. Science treats gravity’s operations on analogy with a magnetic field.

v. Consistent with Newton’s principle, if a body of common or ordinary matter is moved circularly a consistent force must be applied to it by the relevant agent. The greater its mass, the greater the force that agent must exercise to overcome its rectilinear inertia. But in aether’s realm circular motion is prior to centripetal force. The greater the force aether exercises in ‘draw[ing] aside from the rectilinear motion which otherwise [the celestial body] would pursue’, then, the greater the centripetal (gravitational) force generated. Thus, while gravity appears to be a force intrinsic in a body this is but a consequence of aether’s undetected extrinsic action.

vi. As to the speed with which gravitational force is generated, we repeat certain points made in an earlier article, namely, that—

To these we add the assessment that aether is immobile with respect to every body of ordinary matter. This last would explain why C is the same in every frame of reference. Einstein contended that C was the one fixity in the universe. What he attributed to light ought, on our thesis, to have been attributed to aether for it is this body which is the immoveable on which all celestial motion depends.[42] . In generating circular motion aether exercises over celestial bodies the accident action. Einstein's General Theory of Relativity has been proven by observation. It requires that any change in a 'gravitational field' take place also at the speed C. We were inclined to think Newton's view, that gravitational force is instantaneous, was to be preferred [43], but Einstein's view cannot be ignored. Moreover, principle demands that action be constrained by matter's inertia. [This paragraph amended 1st September, 2015]

vii. Newton confessed himself unable to explain gravity as action at a distance. Einstein thought he had solved the problem with his elaboration of a gravitational field theory but he had only provided a more precise explanation of how gravity operates. If it is understood that its cause is one body, one substance, that acts on all bodies of ordinary matter, the dilemma of ‘action at a distance’ disappears.

i. But is this thesis not contradicted by what we observe of the influence of the moon and, to a lesser extent, the sun on the seas which cover some seventy per cent of the earth’s surface? If gravity is caused not by something intrinsic to a celestial body but by this extrinsic influence, aether, how explain the clear influence of the moon and of the sun on the regular movements and alterations in movements of the tides ? Science tells us that the moon’s influence on the tides is the greater.

ii. The moon’s involvement in the tides may be seen in the way the diurnal period between successive tides reflects the lunar day, about 24 hours 50 minutes. A cause exercises influence unto the be (esse; existence) of a thing dependent in regard to its be.[44] Causes may be distinguished according as they are essential, or not, to the effect; that is, a cause may exercise its causality per se or per accidens.[45] Of any effect there are four per se causes, no more and no less as outlined above. (IV, i).

Causes per accidens fall into three categories condition, occasion and chance. Of these one only concerns us here, condition (removens prohibens), without whose operation a cause per se cannot act.[46] Now the moon is more than a condition of the motions of the waters that cover the earth ; it is essential to their regularity. It must, then, be a cause per se. It is not a formal or material cause for these are always intrinsic, while the moon is extrinsic to the earth and its motions. It is impossible that it be the final cause, their end or reason, for this is something intended by nature’s author. It remains that the moon is an efficient cause, if subsidiary to the principal efficient cause, that intellectual substance the Philosophers have identified. Hence the moon operates in the capacity of instrument. But there are degrees of instrumentality.

iii. Science’s explanation that the tides are caused by the ‘pull’ of the moon is problematic if for no other reason than that there is nothing in the mass of a celestial body qua mass which demands that it should attract another. Moreover, if the moon exercised a ‘pull’ on the waters of the seas of the earth at a point immediately opposite it, one would expect a general movement of the mass of surrounding seas towards that point, qualified by their inertia. But, given that that point on the earth’s surface is rotating away from the moon at a steady rate (about 460 metres per second at the Equator) to the east, one would expect the two forces to produce a piling of the waters to the east and corresponding diminution in waters to the west. But this is not what happens.

A ‘bulge’ of waters, a high tide, occurs with the moon’s passing, though not necessarily opposite the moon’s meridian, but the waters mass uniformly and, as uniformly, diminish with the earth’s rotation, albeit with amplitudes which differ from place to place. But, even stranger, the massing that occurs in the hemisphere adjacent to the moon is balanced by a corresponding massing in the opposite hemisphere. The total effect is a relatively even pulsation, analogous to an animal’s breathing, with nodes on opposite sides which process steadily about the globe.

iv. Although we take the rotations of earth and moon as simple circles about their axes, their motions are more complex. The planet and its satellite each has an effect on the other, a function of their respective masses. The moon is 1/81st the mass of the earth, its relative density 3.36 to the earth’s 5.5.[47] Its average distance from the earth is some 384,000 km. In accordance with Newton’s laws it appears to influence the earth in direct proportion to its mass and inverse proportion to the square of the distance between their centre of masses. The earth appears to influence the moon in a similar fashion.

The combined masses, separated though they be by some 380,000 odd kilometres, circle about a focus (the centre of the two masses, their centre of gravity) called the barycentre. This is located within the body of the planet at a point opposite the moon an average 4,670 km from the earth’s geometric centre (some 1,700 km beneath its surface).[48] The moon moves in the same direction the earth is rotating, anti-clockwise.[49] But in the time it takes the earth to rotate 360° the moon progresses only 12.2°.[50] The consequence of this disparity is that the barycentre beneath the earth’s surface moves in the opposite direction to the earth’s rotation, somewhat after the fashion of the phenomenon known as mechanical precession.[51] It moves slightly slower for its locus, aligned between earth’s centre and that of the moon, traverses 348° in the time the earth rotates 360°.[52]

v. The barycentre exercises on the components of the earth’s surface a centripetal force additional to that exercised by the earth’s centre of gravity.[53] This barycentripetal force resolves into two subsidiary forces on the waters to east and to west of a point above the barycentral focus, one directed towards the earth’s centre and the other towards a point on the surface directly above it.[54] This horizontal component force draws the waters from east and west, from north and south, towards that point.[55] Under this influence the tides progress from east to west, though the interference of continents, the varying depths of the oceans, the coriolis effect and other factors, produce a complex of movements. These are manifest in a pattern of cotidal lines (lines joining points of identical tidal phase) radiating around centres which turn clockwise in the southern hemisphere and anticlockwise in the northern.[56]

This contrariety in motions—of the earth’s surface from west to east, of the barycentre from east to west at a slightly slower rate—produces a contrariety of forces which explains, i) why the sea wells and dissipates at a uniform rate with the passage of the barycentre, the momentum of the waters carried to the east matched by the march of the tidal node to the west ; and, ii) why the tides advance by 50 minutes or so every 24 hours. The moon moves progressively from apogee (furthest away) to perigee (closest) every 7½ cycles. As the moon moves closer the barycentre moves closer to the earth’s surface and the horizontal component of the barycentripetal force, assumes greater magnitude. It is this greater force, not a stronger ‘pull’ of the moon, that explains why the tides at such times increase in amplitude.

vi. To the high tides induced by the ever-moving barycentre there correspond highs on the opposite side of the planet. Let us call the first set primary tides and the corresponding ones secondary. There is currently no satisfactory explanation for these secondary tides. All those proposed are premised on the thesis that the moon exercises a ‘pull’ on the earth. But no such hypothetical ‘pull’ on one side of the globe could account for the massing of the seas in the opposite hemisphere away from `‘the pull’. The barycentripetal theory provides for the presence of a horizontal component force similar to that operating on the seas of the primary tides, but much diminished. For, as focus of the secondary tides, the barycentre is beyond the earth’s centre—some 6,500 km, rather than some 1,700 km, distant. Moreover, the secondary tides constitute a reaction to the primary tides. After a primary tide the seas dissipate, with a momentum which lowers them below the mean, producing a low tide. The secondary high rises to fill this gap somewhat as a second wave follows the trough left by displacement of waters of a pond by a boulder. For these two reasons, secondary tides do not rise to the same heights, or fall to the same depths as primary tides.

As with primary tides, these secondary tides have four causes. We need concern ourselves only with the extrinsic causes (efficient and final). Their final cause is clear. Without them the centre of mass of the planet would move and the resultant instability adversely affect the regularity of its rotation and its relationship to moon and sun. Again, the ultimate efficient cause is clear, it is the intellectual substance that ensures the planet rotates with due order to ensure the welfare of its parts.

The rhythm of this unremitting cycle—primary high, primary low ; secondary high, secondary low—is reinforced twice each lunar month, i) at the beginning when the moon is in the same quadrant as the sun (new moon), and ii) mid-month when it is in opposition to the sun (full moon).

vii. The moon is, thus, a subsidiary instrumental efficient cause of the movement of the tides in the following subordination:

viii. How does the sun affect the tides? Again there is no ‘pull’ exercised by the sun, although the analogy of attraction is closer than with the moon’s involvement because the location of the sun-earth barycentre is within the body of the sun and close to its centre. The influence operating on the earth’s seas is the centripetal force upon them focussed on the sun-earth barycentre generated by aether’s causation of circular motion of the planet and the sun about that centre.

ix. An interesting problem arises over the relative influence of sun and moon. Notwithstanding its distance, some 149.6 million kilometres (93 million miles ; 8.32 light minutes) from the earth, the sun’s influence, through its mass, is some 179 times that of the moon. Yet the sun’s observed influence on the tides is less than half that of the moon. In an endeavour to solve the problem, current science—grounded, of course, on the thesis that the centripetal force of gravity is one of attraction—opines that the tides on one celestial body are influenced by another not according to the square but perhaps the cube of the distance from that other body.[57]

But if the tides are influenced not by the distances between the relevant bodies but by the distances of their respective barycentres, this modification of Newton’s laws is unnecessary. For in respect of the tides the moon is not competing with the sun as—

Despite the force generated as a result of the sun’s much greater mass, the immensity of the distance from the earth’s seas of the sun-earth barycentre[58] diminishes its influence accordingly.

x. As with the moon then, the sun is an instrumental, but subordinate, efficient cause of the movement of the tides. The subordination here operates as follows:

VII

i. Gravity’s final cause is the ordination and subordination, for the good of the whole, of the material substances that constitute the globe and, in the case of earth, its inhabitants.

Gravity’s formal cause, operating to give effect to the final cause, is the inclination towards that centre or focus, the consequence of the circular motion induced in a celestial body and its component parts by aether, the heavenly body. Its formal cause explains why gravity appears to be a force of attraction. As the house-plan realised is the term of the work of construction of a house (its final cause) unless something (e.g., an obstruction ; defective materials) impedes it, so attainment of the centre of mass of the celestial body is the term of the work of gravity, unless something (other matter) impedes it.

Gravity’s material cause is the celestial body and its component parts moved circularly, i.e., against their natural, rectilinear, inclination.

Gravity’s principal efficient cause is the intellectual substance which orders the universe. Gravity’s instrumental efficient cause is aether.

ii. It is characteristic of natural things that the speed of progression increases as they approach their term. This is the philosophical reason why a body accelerates as it approaches the centre of a celestial body. It is this principle, too, working with the relative densities of the component elements of the celestial body, which assists the right ordering of its parts. For, were it otherwise, gases as the least dense of its components would not rise above all others ; and water, less dense than the generality of minerals, would not rise above them but be admixed with them in confusion. Hence, the formal cause of gravity, that which determines the matter so that the end (final cause) of the operation is achieved, ensures that the inclination towards the centre is greater the closer another body approaches it.[59]

iii. In an earlier paper we remarked on the relationship between aether and light and offered the conclusion that aether is universally the vehicle of light’s transmission.[60] In the performance of its function as lucifer, as in those functions that relate to the very structure of bodies and the conduct of celestial bodies, each of them essential to the works of creation, aether might be called a pure instrument.[61] Consistent with our thesis, whether at the level of the infinitesimally small, where it assists in binding atomic and molecular structure, or at the level of the infinitely great where it holds together each solar system, each celestial body, the very universe itself, aether operates unobtrusively and in undetectable fashion.

Michael Baker
15th August 2013—Solemnity of the Assumption of the Blessed Virgin

[1] In I De Caelo, Prologue.

[2] Cf. http://en.wikipedia.org/wiki/Newton%27s_theory_of_gravitation#Newton.27s_reservations

[3] Principia Mathematica Bk. III, General Scholium. “I have not been able to discover the cause of [the] properties of gravity from phenomena, and I frame no hypotheses… [I]t is enough that gravity… acts according to the laws which we have explained…”

[4] Cf. http:en.wikipedia.org/wiki/Le_Sage%27s_theory_of_gravitation

[5] Summa Theologiae, I, q. 32, art. 1, ad 2.

[6] The Rock

[7] On the absolute impediment of void, if it did exist, to the passage of any material thing see Aristotle, Physics, Bk. IV, vi (213b 30 et seq.) and St Thomas’s Commentary, In IV Physics L. 10.

[8] Literally, the fifth essence. The four material essences of philosophical antiquity were earth, air, fire and water. Aether was the fifth.

[9] Physics Bk. VIII. This is clear for things inanimate ; not so clear for the animate differentiated precisely in the fact that they do move themselves. These have an interior principle, a soul, which causes their movement (whether as to execution only (plants), as to execution and form (brute animals), or as to execution, form and end (rational animals). But even the animate, Aristotle shows, is ultimately moved by another. This process of being moved cannot proceed to infinity : there must, therefore, be a first unmoved mover of all other beings.

[10] Whence we get the colouration of the term ‘quintessence’.

[11] Cf. Christopher A Decaen in Aristotle’s Aether and Contemporary Science, The Thomist, 68 (2004) 375, footnote 50.

[12] Cf. Christopher A Decaen in Aristotle’s Aether and Contemporary Science, op. cit., footnote 51. Apparently St Thomas did not comment on Bk. 1, Pt. 6 of Aristotle’s De Generatione et Corruptione. Note that here St Thomas includes with the heavenly substance, aether, the celestial bodies, Sun, Moon, stars and planets which seemed to be part of it.

[13] Which must be understood rightly. Ultimately, every material thing, even the automotive (the living), is moved by the First Mover, God. Intermediately, things are moved by instrumental causes and under different respects, moved in as many ways as there are species of motion (cf. II, iv above). Aether is such an instrumental cause, perhaps the most fundamental in the material order.

[14] One critic has suggested that the assertion of the fourfold constitution of the elements of the material world accepted by the ancient Greek philosophers is reflected in the modern division of material structures into solids, liquids, the gaseous and plasma.

[15] In I De Caelo, L 2, 17.

[16] In I De Caelo, L. xviii, n. 7

[17] Notably M31, Andromeda Galaxy, and M33, Triangulum Galaxy. Those who contend that the motion of the earth and of other planets and satellites is not circular but elliptical are splitting hairs. Whatever the effects of the modifying influences, the motion is primarily and per se circular.

[18] For if it is lost the thing ceases to be. For living things, Aristotle teaches, to live is the same as to be.

[19] Though, for each celestial body there remains ‘a still point of the turning world’, to quote T S Eliot [The Four Quartets]. While no such body is absolutely immobile due to the influence, as science perceives it, of other celestial bodies, each such body is yet relatively so. St Thomas sheds light on the issue where he deals with an objection to Aristotle’s view that circular motion is a simple motion.
[T]he parts of a sphere which is in circular motion are not in uniform motion but the parts near the poles or near the centre are moved more slowly because they traverse a smaller circle in a given time; consequently the motion of a sphere seems to be composed of fast and slow motions. His answer is instructive: But it must be said that a continuum does not have parts in act, only in potency. Now what is not in act is not in actual motion. Hence the parts of a sphere, since they form a continuous body, are not actually being moved. Hence it does not follow that in spherical or circular motion there is diversity actually, only potentially. [ In I De Caelo, L iii, 26].
Transported on the surface of the Earth at a rotational speed of 465 metres per second (at the equator), we are quite unconscious of the motion. One critic has advanced against this that the reason is that the earth’s motion is uniform, not bumpy. We leave this to others to resolve.

[20] This experiment, deemed a failure because it failed to produce a result that accorded with modern science’s materialist preconceptions, was in fact a success. It proved what the Philosophers had maintained for centuries, aether’s superiority to the limitations of ordinary matter.

[21] This characteristic may offer an explanation as to the uniformity of C, the speed of light. As is well known, in every frame of reference its speed is constant at 299,792,458 metres per second.

[22] Dorothy L. Sayers’ fictional detective in The Unpleasantness at the Bellona Club, London (Victor Gollancz Ltd.), 1921, Ch. XV. This (admittedly flippant) citation is from Aristotle’s Poetics (cf. Bekker 1460a) where the context is human making (the artificial) rather than some element of the natural order.

[23] Letters to Dr Richard Bentley, 1692-3.

[24] It may be objected that magnetic attraction between two bodies of iron involves an efficient cause which is intrinsic to the effect, but it is not so. The efficient cause of magnetic attraction is that extrinsic influence establishing in its nature the property that one body of iron will attract another.

[25] nbsp; The constitution of a body involves two contrary principles, one of being determined (prime matter), the other of determining (substantial form). St Thomas addresses the issue directly in II, ix above when he says this element is to all other bodies as form is to matter, as act is to potency.

[26] A point well made by Christopher A Decaen in Aristotle’s Aether and Contemporary Science, op. cit., Part I and footnote 40. This is also the reason why we cannot detect the substance, for every sense requires some reaction to the sense power in the thing sensed.

[27] The nature of a thing determines how it operates.

[28] In Book VIII of the Physics. Cf. St Thomas’s Commentary In VIII Physics, L 23: 1168

[29] Descartes is the philosopher responsible for the shift of meaning so that it has become synonymous with first accident, quantity. Cf. D. G. Boland Ll. B., Ph. D., God and the Theory of Everything, 2012; the text will be available shortly from Sydney’s Centre for Thomistic Studies whose website is http://www.cts.org.au/

[30] And, be it noted, not all substances are corporeal substances. Some have no bodies.

[31] In his text, God and the Theory of Everything, (2012), Dr D. G. Boland of Sydney’s Centre for Thomistic Studies, points out that that Descartes rejected the metaphysical understanding of substance and substituted for it first accident, quantity. The text will be available shortly; cf. http://www.cts.org.au/

[32] John of St Thomas, Cursus Phil., I, p. 609b, quoted in Ostensive Metaphysics, Treatise One, Ontology, A. M. Woodbury Ph. D, S.T.D., a text of Sydney’s Aquinas Academy, n. 1161.

[33] It is not clear just how many of the nine accidents are properly to be attributed to aether. We remarked in the earlier paper the difficulties presented by the nature of this substance.

[34] This analysis is reproduced from the text of A. M. Woodbury Ph. D, S.T.D, of Sydney’s Aquinas Academy, General Natural Philosophy and Cosmology, c. 22, 1, nn. 334 et seq.

[35] This, the proper sense of ‘centrifugal’, is illustrated in the operation of an explosion.

[36] Sir Isaac Newton, Principia Mathematica, Definition V; Axiom I. (Transl. from the Latin by Andrew Motte revised by Florian Cajori, University of California Press, 1934). My copy, a reprint in The Great Books of the Western World, vol. 34, for Encyclopaedia Brittanica, Inc. 1952.

[37] University of California, Irvine. I have rewritten the final formula to reflect the earlier mode of expression http://learn.uci.edu/oo/getOCWPage.php?course=OC0811004&lesson=006&topic=10&page=1

[38] Principia Mathematica, op. cit., Definition I

[39] Cf. The entry on Mass on the Wikipedia website, http://en.wikipedia.org/wiki/Mass

[40] The inability of science to plumb the nature of mass is understandable for science is not concerned with the natures of things. A substance, as we have noted, is something which exists in itself (be-in-self) not in another, an accident a reality which exists not in itself, only in some substance (be-in-other). The first accident is quantity. Metaphysically understood, then, the mass of a body consists in corporeal substance as affected by quantity. But there is, as Newton remarked, another influence too, that quality which is the substance’s proper density. Substance explains the specific differences between masses, quantity explains the individual differences between them, while density, the quality proper to each substance, explains why one type of substance differs from another in specific gravity. “The action of a generant does not stop at the bare substance but produces it equipped with the accidents upon which the substance depends, that it may exist and operate.” (John of St Thomas; Curs. Phil. II, ed. Reiser, p. 268b, quoted in A M Woodbury, General Natural Philosophy and Cosmology, op. cit., nn. 127 and 344.) The substance of copper (that immaterial reality which is copper), for instance, differs from the substance of water (that immaterial reality which is water), as the density which is the quality proper to copper differs from the density proper to water. One mass of copper differs from another, as one mass of water differs from another, through their respective quantities. [This analysis from A M Woodbury Ph D, S.T.D., General Natural Philosophy and Cosmology, op. cit., nn. 238 to 245. ]

[41] Science and Aristotle’s Aether at http://www.superflumina.org/PDF_files/aether_science.pdf

[42] Rather C’s fixity is a property of aether demonstrating its immobility and fixity.

[43] Newton seemed to treat ‘space’ as if it was an ethereal body while Einstein, at least until he amended his view in 1920, treated it as non-being somehow existing. His amended view did not seem to regard ‘ether’ as much more than an accident of ‘space’, albeit he was correct when he said that it was not to be considered as comprised of parts trackable through time or of ponderable matter.

[44] This principle is elaborated by St Thomas Aquinas in Summa Theologiae I, q. 104, art. 1.

[45] Aristotle Metaphysics Bk. V, ii. and Physics Bk. II, vii (198a 5 et seq,) ; St Thomas In II Physics L. 10.

[46] For a detailed analysis see the material under the heading ‘The Mode of Aether’s Involvement’ in Science and Aristotle’s Aether at http://www.superflumina.org/PDF_files/aether_science.pdf

[47] For this and what follows see for example Steve Massey, Exploring the Moon, Sydney, 2004.

[48] Cf. http://en.wikipedia.org/wiki/Barycentric_coordinates_(astronomy)

[49] So, too, the motion of the Earth around the Sun is counter clockwise viewed from the north.

[50] Hence the Moon advances from west to east some 49 minutes every day. Taken with respect to distant stars, the Moon takes 27.32 days to orbit the Earth (sidereal month). But because the Earth is itself moving circularly around the Sun and, in one cycle of the Moon, traverses about 1/ 12th of its annual cycle, the Moon takes about 29.53 days (synodic period, or synodic month) to pass from new moon to new moon.

[51] Mechanical precession is the movement of a round part in a round hole where the direction of rotation of the inner part is opposite to the direction of rotation of the radial force.

[52] Cf. the title ‘Tides’ at http://en.wikipedia.org/wiki/Tides

[53] For it is a function of the two masses rather than the earth’s alone.

[54] The surface of a fluid of uniform density..., if at rest, is everywhere perpendicular to the lines of force ; for if this were not so, the force at a point on the surface could be resolved into two components, one perpendicular and the other tangent to the surface… (Anthony & Brackett, Elementary Text-book of Physics, p. 127.)

[55] Though due to water’s inertia this welling occurs some time after the barycentre has passed.

[56] > Cf. http://en.wikipedia.org/wiki/Tides for the reproduction of these lines on a homolographic projection of the earth analogous to lines on a topographic map [M2_tidal_constituent.jpg] .

[57] Cf. https://en.wikipedia.ord/wiki/Tide under the heading ‘Forces’

[58] Some 149.3 million km : close to the sun’s centre.

[59] Which facility is recognised in the inverse square law.

[60] Cf. the author’s study on the function of aether as the substance of which light is the proper accident at http://superflumina.org/PDF_files/aether_science.pdf

[61] There is a parallel in philosophical psychology in the field of knowledge where the objective concept has no reality save as instrument to serve the intellect : it is a pure sign or a pure instrument.