Though previously a popular scientific concept (in the form of the lumeniferous aether), the notion of an aether (ether) had essentially become taboo in science after the infamous Michelson-Morley (M-M) experiment supposedly disproved its existence in 1887, even though at best (or worst) all it did was seemingly to disprove the existence of an inert material or mechanical aether, hanging in the air like a gas. The adoption of Einstein’s relativistic theories where space-time was dependent on (relative to) an observer’s speed ruled out an aetheric medium which rationally offered a single universal metric for space and for time.


Gregg Braden, in The Divine Matrix, has referred to the M-M experiment as “history’s greatest ‘failed’ experiment.” Independent researcher Gary Novak adds that the M-M experiment “failed to find an etheric medium in space for conducting light waves. In fact, it failed to produce any result. A looked-for diffraction pattern did not appear.The absence of a result is not a valid basis for conclusions in science. Any number of explanations exist for the result.” Continuing, Novak states frankly: “Failing to find the etheric medium should have meant nothing…and a recent mathematical analysis is said to show that if the curvature of the earth were taken into account, the result would have been different.”

Other researchers have expressed the view that it is ‘totally absurd’ to consider Einstein’s relativity and the M-M experiment to be a disproof of an underlying aetheric medium.(1) As independent scientist Paul LaViolette points out in Genesis of the Cosmos, the aether theory wasn’t abandoned because of experimental disproof; it just went out of style. In contemporary particle physics, the aether has its counterpart in the zero point field (ZPF) and zero point energy—the quantum foam seething with its endless array of virtual particles bubbling momentarily into our reality and vanishing just as quick. We need to stress: The aether is not physical (like a gas), but it does evince physical effects. In fact, it is the ZPF/aether and its abundant quantum activity that create and sustain matter itself.

Henry C. Warren has pointed out that the M-M experiment “was an invalid test” and explains that “what general relativity did in effect was to rename ether and call it space. This model preferentially uses expressions such as fabric of space or medium in space, without spelling out precisely the nature of that fabric or medium” (emphasis added). He adds that an model and any other model that is based on the inflow of a spatial medium or fabric…can meet all the same experimental tests that led to the acceptance of general relativity.”(2)

Indeed, Einstein had said: “Time and space and gravitation have no separate existence from matter…Physical objects are not in space, but these objects are spatially extended. In this way the concept ‘empty space’ loses its meaning…The particle can only appear as a limited region in space in which the field strength or the energy density are particularly high.”(3) In a 1920 lecture, after his theory of general relativity was fully developed, Einstein acknowledged the necessity for aether, and did so again in his book Relativity.(4)

As the aether theory illustrates, the spatial/aetheric inflow towards the center of a celestial body creates the ‘pull’ of gravity and the so-called ‘curvature’ of Einstein’s relativistic ‘curved space,’ which is merely the aetheric medium renamed. Space is not curved but Euclidian in this view. In a heated defense of the 1933 Dayton Miller aether experiments, James DeMeo asserts that in combination, the small Michelson-Morley drift and the greater drift of the Dayton Miller experiments, which were performed at a higher altitude, actually support an entrained aether theory.(5) In 1986, the journal Nature reported on the results of experiments conducted with more sensitive equipment than what was available to Michelson and Morley. A field with the characteristics of the aether was detected, and it behaved just as the older predictions had suggested it would a century before. It was “precisely linked to the motion of the earth through space, just as had been predicted!”(6)

There were several theories that were proposed to explain the initial M-M null result, including Einstein’s Special Relativity. Michelson, himself a Nobel laureate, rejected the Special Relativity theory and championed the ‘(a)ether drag’ theory, which had been proposed as early as 1831.(7) Experiments by Michelson and Gale actually supported the case for a ‘physical’ vacuum, though fundamentalized relativistic Science prefers to ignore this.(8) Though the Priesthood of Official Science would never let on, many have criticized the theoretical removal of the aether, including Michelson himself.(9) Other researchers have attempted to correct the misconception of the apparently failed aether hypothesis through the years, with little success, due to the perceived prestige of Einstein’s entrenched theories and the assumptions carried with them.

In fact, the experiments and research of Georges Sagnac (early 1900s), Herbert Ives (mid-1900s), Panagiottis Pappas (1983), Ernest Silvertooth (1987), Peter Graneau (1980s), and others (including Ampère) have rendered invalid both special relativity and general relativity, “and with [GR] goes the expanding-universe theory.

The Expanding Universe ( Source >> )

Consequently the entire edifice of modern relativistic cosmology has begun to crumble.”(10) (Einstein’s GR equations demanded an expanding or contracting universe which caused him to introduce the cosmological constant notion whose purpose was to ensure a stationary space-time continuum, which he believed in. LaViolette states the expanding/Big Bang universe idea is not compatible with today’s scientific evidence and does not afford the universe enough time to create stars and galaxies.)(11)

Scientist and aether researcher David Thomson laments on his blog the nonsensical stance mainstream physics has taken towards the aether and the fabric of reality and asks how much longer it will be before the popular PC theories essentially collapse under their own weight:

Mainstream science tells us the Aether does not exist because it is not physical. However, mainstream science talks about ‘electrical currents’ and ‘twisted magnetic field lines’ as though they were physical objects…current is not a physical object of itself. Also, magnetic field lines are considered by mainstream science to be mathematical structures, not physical structures. Like the Aether, magnetic flux lines are non-material. Students of the Aether Physics Model clearly understand that magnetic flux lines are Aether structures. So the acknowledgement of the reality of magnetic flux lines is the acknowledgement of the reality of Aether! The more science learns the truth about existence, the closer they are getting to returning to the Aether theories of the past. How much more strain can mainstream science take before they are forced to recognize the Aether Physics Model?(12)

Long-time researcher Tom Bearden has also lamented the peculiar psychology of mainstream research regarding the potential of tapping the aether/vacuum for infinite energy.(13) This is science in the theoretical no-man’s land of aether-lessness. Wilcock is frank:

We now know that an ‘aetheric’ science is the only remaining model of the Universe that fits together with the evidence that is now available. Current theories working with these aether concepts…all agree that our physical reality arises from this hidden energy substance, which creates all that we know and see by vibrating.(14)

The highly respected physicist Paul Dirac wrote in an article in Nature in 1951 that “we must make some profound alterations to the theoretical idea of the vacuum,” and added that “with the new theory of electrodynamics we are rather forced to have an aether.” Over fifty years on, Dirac’s words are even more pertinent. Others who have devoted many years of their life to promoting the aether theory are: Maurice Allais (Nobel Prize 1988—Economics), Harold Aspden, Steven Rado, Ken H. Sato, Gordon L. Ziegler, and many others. The list of anti-relativity scientists is even longer (generally scientists are anti-relativity because the verifiable formulas of relativity can be derived from classical physics and in fact many of the formulas used in relativity existed before relativity). Many scientists are both pro-aether and anti-relativity.(15) There are many experimental effects and research data that essentially necessitate an aetheric model, as noted. An incomplete list includes:

The Casimir effect wherein two parallel plates held very close to each other are pushed together by the virtual frequencies of the vacuum/aether surrounding them.(16)

The Aspden effect demonstrated that an object that has been rotated and returned to a stationary position can then be accelerated up to the same speed again using less energy than on the first go—feeding off the spiralling aetheric torsion energy like a sponge, seemingly lessening its mass.(17)

The DePalma effect shows that when two balls—one of them spinning rapidly and the other not—are catapulted at the same speed and angle through a vacuum, the one that is spinning will travel higher, fall faster, and move farther overall than its non-spinning counterpart, defying all known ‘laws’ of physics—as if the torsion energy of the aether is harnessed by the ball’s spin, affecting an apparent lessening of its mass.(18)

Russian biophysicist S.E. Shnoll’s 30-plus years of research reveal the existence of a previously unknown relationship between fluctuations in the rates of radioactive and other processes in the laboratory, and major astronomical cycles, including the day, month, and year,(19) all of which would not be possible without the unifying harmonics of a ZPF or aether.

Russian electrophysiologist Dr. A. Podshibyakin discovered that by charting acupuncture points, a correlation is revealed between the ‘bioplasma’ (human subtle energy/fields) and changes on the surface of the sun—at the exact moment solar flares occur, there are changes in the electrical potential of the skin’s acupuncture points. In some way, the ‘bioplasma’ of the body is sensitive to these explosions the instant they occur, even though it takes about two days for the cosmic particles to actually reach the Earth. Podshibyakin also established a correlation between solar flares and significant increases in road accidents. Incidentally, it is cases like this that prove one of the fundamental underlying principles of astrology. Most interesting from an astrological point of view is the related evidence of John H. Nelson, a radio engineer, who has discovered that magnetic disturbance in the Earth’s atmosphere (which corresponds to the incidence of solar flares) can be predicted according to the conjunctions and aspects formed by the major planets. When the planets line up in the traditionally ‘inharmonious’ angles, magnetic disturbance is strongest; when they line up in traditionally ‘harmonious’ angles, it is weakest.(20) For instance, Nelson found that sunspots and therefore radio disturbances occurred when two or more planets were in line, at right angles, or arranged at 180° to the sun.(21)

Numerous predictions were made by LaViolette based on his subquantum kinetics (aether) model, which were ultimately borne out by astronomical observation—one such prediction, made in 1985, being that light is in fact not a constant throughout the cosmos (vindicated in 2007 by astronomers).(22) Another postulation subsequently validated by observation was that dwarf elliptical galaxies evolve into spirals and that spirals in turn gradually evolve into giant ellipticals.(23) Such predictions are not made in conventional cosmology. From that perspective, such findings are ‘anomalous.’

Dr. Eli Cartan discovered in 1913 that the fabric (flow) of space and time in Einstein’s general theory of relativity not only ‘curves’ but also possesses a spinning or spiraling movement within itself known as ‘torsion’ or torsion fields. It is now generally accepted that the space surrounding the Earth and perhaps the entire galaxy has ‘right-handed spin,’ meaning that energy is influenced to spin clockwise as it travels through the physical vacuum.(24)

The work of Russian scientist Nikolai Kozyrev (1908–83) showed that by shaking, spinning, heating, cooling, vibrating, or breaking physical objects, their weight can be increased or decreased by subtle but definite amounts, as a result of these manipulations’ effect on the aetheric energy in which these objects are immersed.(25)

In the 1990s, Evgeny Podkletnov engineered a ceramic donut-shaped superconductor ring that shielded gravity by 2–5% in objects placed over it as it spun at 5000 RPMs. A funnel of gravity 30 centimeters above and below the device was also identified.(26)

Kozyrev proved decades ago that torsion fields travel at superluminal speeds. Such a superluminal energy, separate from gravity and electromagnetism (and even more fundamental), represents a significant breakthrough in physics—one that demands, as Wilcock observes, that a ‘physical vacuum,’ ‘zero-point energy’ or an ‘aether’ must really exist.(27)

Torsion fields that travel far beyond light speed must do so in hyperspace. This means the aether and its different density levels are hyperspace itself; ‘parallel’ dimensions/virtual realities that have given birth to our own, though the flow of energy and information is reciprocal: our reality can influence hyperspace and vice-versa (See my article ‘Junk’ DNA: An Interdimensional Doorway to Transformation? for how DNA fits in with this idea on a more personal level). With this conception we have moved far beyond the idea of aether as a gas-like substance lingering in the air and into concepts that once belonged to science fiction.

Theoretical and conceptual genius and long-time researcher, Lt. Col. Tom Bearden can speak with some authority on the subject. He observes:

“Every fundamental constant of nature is dynamically constructed from—and due to—the zero-point, virtual vacuum interactions that constitute ‘empty’ space. The virtual ‘sea’ of seething waves and particles that is empty vacuum is actually an ether—a Lorentz-invariant, nonmaterial (virtual) ether, perfectly admissible by the Michelson-Morley experiment and the entire experimental basis of physics. Indeed, Einstein once proposed naming the vacuum and its contained fields the ‘ether,’ but his suggestion was not heeded.”(28)

In TGI 1 (and 2) I show the reader that the aetheric medium and its torsion fields are the key to life itself, and the foundation and sine qua non of both consciousness and a science thereof. Science of the 21st and 22nd centuries is and will be aether/consciousness science.


(1) See Kehr, The Study of Ether, Ch. 1.
(2) Warren, The Entrained Spatial Medium Gravitational Sink Model.
(4) Warren, Op. cit.
(5) Warren, Op. cit.
(6) Braden, The Divine Matrix, 19–21.
(7) See Kehr, 8.
(8) Yurth, Seeing Past the Edge, 140.
(9) Further reading on Michelson-Morley and aether: , and . See also for Dayton Miller’s aether drag experiments: .
(10) LaViolette, Genesis of the Cosmos, 270–2.
(11) Ibid., Ch. 13.
(12) Thomson, Aether in Space is Fluid.
(13) Tom Bearden, Energy Density of the Vacuum.
(14) Wilcock, The Science of Oneness, Ch. 2.
(15) See Kehr, Ch. 1.
(16) See Murphy, TGI 1.
(17) Aspden, Discovery of Virtual Inertia. See also Wilcock’s ‘Convergence’ series.
(18) See Wilcock, The Science of Oneness, Ch. 4.12 and Divine Cosmos, Ch. 1.12. See also .
(19) Tennenbaum, Russian Discovery Challenges Existence of Absolute Time. .
(20) Astrology. .
(21) Watson, Supernature, 38.
(22) LaViolette, Subquantum Kinetics. See also Yurth, Seeing Past the Edge, for more on the speed of light as a constant idea.
(23) LaViolette, Subquantum Kinetics, 94.
(24) See Wilcock, The Aether Science of Dr. N.A. Kozyrev, Nexus, 14(3).
(25) Ibid. See also the Convergence series, in particular The Divine Cosmos, Ch. 1, for how Kozyrev identified torsion.
(26) Jones, 169.
(27) Wilcock, The Aether Science…
(28) Bearden, Excalibur Briefing, 258-61.

Copyright 2011 Brendan D. Murphy

About the Author

Brendan D. Murphy is an independent researcher and author who has been studying metaphysics, the occult, physics, and related subjects since a profound metaphysical awakening around the age of twenty. Now twenty-eight, Brendan has spent the past four years researching and assembling his forthcoming book series The Grand Illusion on a full-time basis in preparation for release in 2012.
To contact Brendan, view free book excerpts, or to just stay updated on developments, visit his new fan page at:

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PS 1: Aether History

In Plato’s Timaeus (St-55c) Plato described aether as that which God used in the delineation of the universe. Aristotle (Plato’s student at the Akademia) included aether in the system of the classical elements of Ionian philosophy as the “fifth element” (the quintessence), on the principle that the four terrestrial elements were subject to change and moved naturally in straight lines while no change had been observed in the celestial regions and the heavenly bodies moved in circles. In Aristotle’s system aether had no qualities (was neither hot, cold, wet, or dry), was incapable of change (with the exception of change of place), and by its nature moved in circles, and had no contrary, or unnatural, motion. Also, aether was supposed to be the heavens. Medieval scholastic philosophers granted aether changes of density, in which the bodies of the planets were considered to be more dense than the medium which filled the rest of the universe. Robert Fludd stated that the aether was of the character that it was “subtler than light”. Fludd cites the 3rd century view of Plotinus, concerning the aether as penetrative and non-material.

Aether theories in early modern physics proposed the existence of a medium, the aether (also spelled ether, from the Greek), meaning “upper air” or “pure, fresh air”), a space-filling substance or field, thought to be necessary as a transmission medium for the propagation of electromagnetic waves. The assorted aether theories embody the various conceptions of this “medium” and “substance”. This early modern aether has little in common with the aether of classical elements from which the name was borrowed.
Although hypotheses of the aether vary somewhat in detail they all have certain characteristics in common. In 19th century theories, aether is considered to be a physical medium occupying every point in space, including within material bodies. A second essential feature is that aether’s properties give rise to the electric and magnetic phenomena and determines the propagation velocity of their effects. Therefore the speed of light and all other propagating effects are determined by the physical properties of the aether at the relevant location, analogous to the way that gaseous, liquid and solid media affect the propagation of sound waves. The aether is considered the overall reference frame for the universe and thus velocities are all absolute relative to its rest frame. Therefore, in this view, any physical consequences of those velocities are considered as having an absolute, i. e. real effects.
Einstein found the non-aether theory simpler and more elegant, but Bell suggests that doesn’t rule it out. Besides the arguments based on his interpretation of quantum mechanics, Bell also suggests resurrecting the aether because it is a useful pedagogical device. That is, many problems are solved more easily by imagining the existence of an aether.

PS 2: Ether and the Theory of Relativity

Albert Einstein, an address delivered on May 5th, 1920, in the University of Leyden.

The original version is available in the Collected Papers of Albert Einstein.

See also the Einstein Archives Online.

HOW does it come about that alongside of the idea of ponderable matter, which is derived by abstraction from everyday life, the physicists set the idea of the existence of another kind of matter, the ether? The explanation is probably to be sought in those phenomena which have given rise to the theory of action at a distance, and in the properties of light which have led to the undulatory theory. Let us devote a little while to the consideration of these two subjects.

Outside of physics we know nothing of action at a distance. When we try to connect cause and effect in the experiences which natural objects afford us, it seems at first as if there were no other mutual actions than those of immediate contact, e.g. the communication of motion by impact, push and pull, heating or inducing combustion by means of a flame, etc. It is true that even in everyday experience weight, which is in a sense action at a distance, plays a very important part. But since in daily experience the weight of bodies meets us as something constant, something not linked to any cause which is variable in time or place, we do not in everyday life speculate as to the cause of gravity, and therefore do not become conscious of its character as action at a distance. It was Newton’s theory of gravitation that first assigned a cause for gravity by interpreting it as action at a distance, proceeding from masses. Newton’s theory is probably the greatest stride ever made in the effort towards the causal nexus of natural phenomena. And yet this theory evoked a lively sense of discomfort among Newton’s contemporaries, because it seemed to be in conflict with the principle springing from the rest of experience, that there can be reciprocal action only through contact, and not through immediate action at a distance.

It is only with reluctance that man’s desire for knowledge endures a dualism of thls kind. How was unity to be preserved in his comprehension of the forces of nature? Either by trying to look upon contact forces as being themselves distant forces which admittedly are observable only at a very small distance and this was the road which Newton’s followers, who were entirely under the spell of his doctrine, mostly preferred to take; or by assuming that the Newtonian action at a distance is only apparently immediate action at a distance, but in truth is conveyed by a medium permeating space, whether by movements or by elastic deformation of this medium. Thus the endeavour toward a unified view of the nature of forces leads to the hypothesis of an ether. This hypothesis, to be sure, did not at first bring with it any advance in the theory of gravitation or in physics generally, so that it became customary to treat Newton’s law of force as an axiom not further reducible. But the ether hypothesis was bound always to play some part in physical science, even if at first only a latent part.

When in the first half of the nineteenth century the far-reaching similarity was revealed which subsists between the properties of light and those of elastic waves in ponderable bodies, the ether hypothesis found fresh support. 1t appeared beyond question that light must be interpreted as a vibratory process in an elastic, inert medium filling up universal space. It also seemed to be a necessary consequence of the fact that light is capable of polarisation that this medium, the ether, must be of the nature of a solid body, because transverse waves are not possible in a fluid, but only in a solid. Thus the physicists were bound to arrive at the theory of the “quas-irigid” luminiferous ether, the parts of which can carry out no movements relatively to one another except the small movements of deformation which correspond to light-waves.

This theory also called the theory of the stationary luminiferous ether moreover found a strong support in an experiment which is also of fundamental importance in the special theory of relativity, the experiment of Fizeau, from which one was obliged to infer that the luminiferous ether does not take part in the movements of bodies. The phenomenon of aberration also favoured the theory of the quasi-rigid ether.

The development of the theory of electricity along the path opened up by Maxwell and Lorentz gave the development of our ideas concerning the ether quite a peculiar and unexpected turn. For Maxwell himself the ether indeed still had properties which were purely mechanical, although of a much more complicated kind than the mechanical properties of tangible solid bodies. But neither Maxwell nor his followers succeeded in elaborating a mechanical model for the ether which might furnish a satisfactory mechanical interpretation of Maxwell’s laws of the electro-magnetic field. The laws were clear and simple, the mechanical interpretations clumsy and contradictory. Almost imperceptibly the theoretical physicists adapted themselves to a situation which, from the standpoint of their mechanical programme, was very depressing. They were particularly influenced by the electro-dynamical investigations of Heinrich Hertz. For whereas they previously had required of a conclusive theory that it should content itself with the fundamental concepts which belong exclusively to mechanics (e.g. densities, velocities, deformations, stresses) they gradually accustomed themselves to admitting electric and magnetic force as fundamental concepts side by side with those of mechanics, without requiring a mechanical interpretation for them. Thus the purely mechanical view of nature was gradually abandoned. But this change led to a fundamental dualism which in the long-run was insupportable. A way of escape was now sought in the reverse direction, by reducing the principles of mechanics to those of electricity, and this especially as confidence in the strict validity of the equations of Newton’s mechanics was shaken by the experiments with b-rays and rapid kathode rays.

This dualism still confronts us in unextenuated form in the theory of Hertz, where matter appears not only as the bearer of velocities, kinetic energy, and mechanical pressures, but also as the bearer of electromagnetic fields. Since such fields also occur in vacuo i.e. in free ether the ether also appears as bearer of electromagnetic fields. The ether appears indistinguishable in its functions from ordinary matter. Within matter it takes part in the motion of matter and in empty space it has everywhere a velocity; so that the ether has a definitely assigned velocity throughout the whole of space. There is no fundamental difference between Hertz’s ether and ponderable matter (which in part subsists in the ether).

The Hertz theory suffered not only from the defect of ascribing to matter and ether, on the one hand mechanical states, and on the other hand electrical states, which do not stand in any conceivable relation to each other; it was also at variance with the result of Fizeau’s important experiment on the velocity of the propagation of light in moving fluids, and with other established experimental results.

Such was the state of things when H. A. Lorentz entered upon the scene. He brought theory into harmony with experience by means of a wonderful simplification of theoretical principles. He achieved this, the most important advance in the theory of electricity since Maxwell, by taking from ether its mechanical, and from matter its electromagnetic qualities. As in empty space, so too in the interior of material bodies, the ether, and not matter viewed atomistically, was exclusively the seat of electromagnetic fields. According to Lorentz the elementary particles of matter alone are capable of carrying out movements; their electromagnetic activity is entirely confined to the carrying of electric charges. Thus Lorentz succeeded in reducing all electromagnetic happenings to Maxwell’s equations for free space.

As to the mechanical nature of the Lorentzian ether, it may be said of it, in a somewhat playful spirit, that immobility is the only mechanical property of which it has not been deprived by H. A. Lorentz. 1t may be added that the whole change in the conception of the ether which the special theory of relativity brought about, consisted in taking away from the ether its last mechanical quality, namely, its immobility. How this is to be understood will forthwith be expounded.

The space-time theory and the kinematics of the special theory of relativity were modelled on the Maxwell-Lorentz theory of the electromagnetic field. This theory therefore satisfies the conditions of the special theory of relativity, but when viewed from the latter it acquires a novel aspect. For if K be a system of co-ordinates relatively to which the Lorentzian ether is at rest, the Maxwell-Lorentz equations are valid primarily with reference to K. But by the special theory of relativity the same equations without any change of meaning also hold in relation to any new system of co-ordinates K’ which is moving in uniform translation relatively to K. Now comes the anxious question: Why must I in the theory distinguish the K system above all K’ systems, which are physically equivalent to it in all respects, by assuming that the ether is at rest relatively to the K system? For the theoretician such an asymmetry in the theoretical structure, with no corresponding asymmetry in the system of experience, is intolerable. If we assume the ether to be at rest relatively to K, but in motion relatively to K’, the physical equivalence of K and K’ seems to me from the logical standpoint, not indeed downright incorrect, but nevertheless inacceptable.

The next position which it was possible to take up in face of this state of things appeared to be the following. The ether does not exist at all. The electromagnetic fields are not states of a medium, and are not bound down to any bearer, but they are independent realities which are not reducible to anything else, exactly like the atoms of ponderable matter. This conception suggests itself the more readily as, according to Lorentz’s theory, electromagnetic radiation, like ponderable matter, brings impulse and energy with it, and as, according to the special theory of relativity, both matter and radiation are but special forms of distributed energy, ponderable mass losing its isolation and appearing as a special form of energy.

More careful reflection teaches us, however, that the special theory of relativity does not compel us to deny ether. We may assume the existence of an ether,; only we must give up ascribing a definite state of motion to it, i.e. we must by abstraction take from it the last mechanical characteristic which Lorentz had still left it. We shall see later that this point of view, the conceivability of which shall at once endeavour to make more intelligible by a somewhat halting comparison, is justified by the results of the general theory of relativity.

Think of waves on the surface of water. Here we can describe two entirely different things. Either we may observe how the undulatory surface forming the boundary between water and air alters in the course of time; or else with the help of small floats, for instance we can observe how the position of the separate particles of water alters in the course of time. If the existence of such floats for tracking the motion of the particles of a fluid were a fundamental impossibility in physics if, in fact, nothing else whatever were observable than the shape of the space occupied by the water as it varies in time, we should have no ground for the assumption that water consists of inovable particles. But all the same we could characterise it as a medium.

We have something like this in the electromagnetic field. For we may picture the field to ourselves as consisting of lines of force. If we wish to interpret these lines of force to ourselves as something inaterial in the ordinary sense, we are tempted to interpret the dynamic processes as motions of these lines of force, such that each separate line of force is tracked through the course of time. It is well known, however, that this way of regarding the electromagnetic field leads to contradictions.

Generalising we must say this: There inay be supposed to be extended physical objects to which the idea of motion cannot be applied. They may not be thought of as consisting of particles which allow themselves to be separately tracked through time. In Minkowski’s idiom this is expressed as follows: Not every extended conformation in the four-dimensional world can be regarded as composed of worldthreads. The special theory of relativity forbids us to assume the ether to consist of particles observable through time, but the hypothesis of ether in itself is not in conflict with the special theory of relativity. Only we must be on our guard against ascribing a state of motion to the ether.

Certainly, from the standpoint of the special theory of relativity, the ether hypothesis appears at first to be an empty hypothesis. 1n the equations of the electromagnetic field there occur, in addition to the densities of the electric charge, only the intensities of the field. The career of electromagnetic processes in vacuo appears to be completely determined by tliese equations, uninfluenced by other physical quantities. The electromagnetic fields appear as ultimate, irreducible realities, and at first it seems superfluous to postulate a homogeneous, isotropic ether-medium, and to envisage electromagnetic fields as states of this medium.

But on the other hand there is a weighty argument to be adduced in favour of the ether hypothesis. To deny the ether is ultimately to assume that empty space has no physical qualities whatever. The fundamental facts of mechanics do not harmonize with this view. For the mechanical behaviour of a corporeal system hovering freely in empty space depends not only on relative positions (distances) and relative velocities, but also on its state of rotation, which physically may be taken as a characteristic not appertaining to the system in itself. In order to be able to look upon the rotation of the system, at least formally, as something real, Newton objectivises space. Since he classes his absolute space together with real things, for him rotation relative to an absolute space is also something real. Newton might no less well have called his absolute space “Ether”; what is essential is merely that besides observable objects, another thing, which is not perceptible, inust be looked upon as real, to enable acceleration or rotation to be looked upon as something real.

It is true that Mach tried to avoid having to accept as real something which is not observable by endeavouring to substitute in inechanics a mean acceleration with reference to the totality of the masses in the universe in place of an acceleration with reference to absolute space. But inertial resistance opposed to relative acceleration of distant masses presupposes action at a distance; and as the modern physicist does not believe that he may accept this action at a distance, he comes back once inore, if he follows Mach, to the ether, which has to serve as medium for the effects of inertia. But this conception of the ether to which we are led by Mach’s way of thinking differs essentially from the ether as conceived by Newton, by Fresnel, and by Lorentz. Mach’s ether not only conditions the behaviour of inert masses, but is also conditioned in its state by them.

Mach’s idea finds its full development in the ether of the general theory of relativity. According to this theory the metrical qualities of the continuum of space-time differ in the environment of different points of space-time, and are partly conditioned by the matter existing outside of the territory under consideration. This space-time variability of the reciprocal relations of the standards of space and time, or, perhaps, the recognition of the fact that “empty space” in its physical relation is neither homogeneous nor isotropic, compelling us to describe its state by ten functions (the gravitation potentials g), has, I think, finally disposed of the view that space is physically empty. But therewith the conception of the ether has again acquired an intelligible content, although this content differs widely from that of the ether of the mechanical undulatory theory of light. The ether of the general theory of relativity is a medium which is itself devoid of all mechanical and kinematical qualities, but helps to determine mechanical (and electromagnetic) events.

What is fundamentally new in the ether of the general theory of relativity as opposed to the ether of Lorentz consists in this, that the state of the former is at every place determined by connections with the matter and the state of the ether in neighbouring places, which are amenable to law in the form of differential equations,; whereas the state of the Lorentzian ether in the absence of electromagnetic fields is conditioned by nothing outside itself, and is everywhere the same. The ether of the general theory of relativity is transmuted conceptually into the ether of Lorentz if we substitute constants for the functions of space which describe the former, disregarding the causes which condition its state. Thus we may also say, I think, that the ether of the general theory of relativity is the outcome of the Lorentzian ether, through relativation.

As to the part which the new ether is to play in the physics of the future we are not yet clear. We know that it determines the metrical relations in the space-time continuum, e.g. the configurative possibilities of solid bodies as well as the gravitational fields; but we do not know whether it has an essential share in the structure of the electrical elementary particles constituting matter. Nor do we know whether it is only in the proximity of ponderable masses that its structure differs essentially from that of the Lorentzian ether; whether the geometry of spaces of cosmic extent is approximately Euclidean. But we can assert by reason of the relativistic equations of gravitation that there must be a departure from Euclidean relations, with spaces of cosmic order of magnitude, if there exists a positive mean density, no matter how small, of the matter in the universe. In this case the universe must of necessity be spatially unbounded and of finite magnitude, its inagnitude being determined by the value of that inean density.

If we consider the gravitational field and the electromagnetic field from the standpoint of the ether hypothesis, we find a remarkable difference between the two. There can be no space nor any part of space without gravitational potentials; for these confer upon space its metrical qualities, without which it cannot be imagined at all. The existence of the gravitational field is inseparably bound up with the existence of space. On the other hand a part of space may very well be imagined without an electromagnetic field; thus in contrast with the gravitational field, the electromagnetic field seems to be only secondarily linked to the ether, the formal nature of the electromagnetic field being as yet in no way determined by that of gravitational ether. From the present state of theory it looks as if the electromagnetic field, as opposed to the gravitational field, rests upon an entirely new formal motif, as though nature might just as well have endowed the gravitational ether with fields of quite another type, for example, with fields of a scalar potential, instead of fields of the electromagnetic type.

Since according to our present conceptions the elementary particles of matter are also, in their essence, nothing else than condensations of the electromagnctic field, our present view of the universe presents two realities which are completely separated from each other conceptually, although connected causally, namely, gravitational ether and electromagnetic field, or as they might also be called space and matter.

Of course it would be a great advance if we could succeed in comprehending the gravitational field and the electromagnetic field together as one unified conformation. Then for the first time the epoch of theoretical physics founded by Faraday and Maxwell would reach a satisfactory conclusion. The contrast between ether and matter would fade away, and, through the general theory of relativity, the whole of physics would become a complete system of thought, like geometry, kinematics, and the theory of gravitation. An exceedingly ingenious attempt in this direction has been made by the mathematician H. Weyl,; but I do not believe that his theory will hold its ground in relation to reality. Further, in contemplating the immediate future of theoretical physics we ought not unconditionally to reject the possibility that the facts comprised in the quantum theory may set bounds to the field theory beyond which it cannot pass.

Recapitulating, we may say that according to the general theory of relativity space is endowed with physical qualities; in this sense, therefore, there exists an ether. According to the general theory of relativity space without ether is unthinkable; for in such space there not only wonld be no propagation of light, but also no possibility of existence for standards of space and time (measuring-rods and clocks), nor therefore any space-time intervals in the physical sense. But this ether may not be thought of as endowed with the quality characteristic of ponderable inedia, as consisting of parts which may be tracked through time. The idea of motion may not be applied to it.