THEOSOPHY, Vol. 38, No. 9, July, 1950
(Pages 398-401; Size: 10K)
(Number 7 of an 11-part series)
EXTENSIONS OF EVIDENCE(1)
THE NATURE OF LIGHT
IN a letter to Mr. Sinnett, written from Ostend in 1887, Mme. H. P. Blavatsky mentioned that her Teacher was dictating a good deal of material for The Secret Doctrine which she was then writing, about "one Grove, F.R.S." When the two volumes were published in 1888, it was found that "one Grove" was Sir William Grove, F.R.S., who, besides having been a Judge of the High Court, was professor of Natural Science at the London Institution. Students of The Secret Doctrine will be familiar with the citations from Sir William Grove's work, Correlations of the Physical Forces (1846), consisting of lectures given by him at the Institution in 1842. According to H. P. Blavatsky, one of the Adepts said of Grove that "his occult insight was remarkable." In these notes, special attention is paid to his views on Light. He showed in his first lecture that "light, heat, etc., etc. are affections of matter itself, and not a distinct ethereal, 'imponderable,' fluid, (a state of matter now) permeating it" (S.D. I, 484). In the striking words of the esoteric teaching: "Light and heat are the ghost or shadow of matter in motion" (S.D. I, 515).
Just over a hundred years after Sir William Grove's lectures, Prof. E. N. da C. Andrade, F.R.S. (Quain Professor of Physics, London University) has given an address at the same Royal Institution (February 17, 1950) on the subject of the properties of Light. He told his audience that the fundamental question which men of science had long discussed was whether light was, in essence, a kind of wave motion or a kind of subtle particle. Was the more appropriate simple illustration a ripple on the surface of water or a discharge of shot from a gun? What was the theory which would best account for the experimental facts found in the laboratory? The great problem today (Prof. Andrade said) was to reconcile the fact that while light in many ways behaved like a wave motion it also behaved like particles, in that the light energy appeared to be delivered in discrete packets or quanta. It was usually recognized that the phenomena of interference, diffraction and polarization showed that light was a transverse wave motion. On the other hand, peculiar features of the action of light in releasing electrons from metals (the photo-electric effect) pointed to a particle nature of light.
The development of the theory of light during the nineteenth century was summarised in a radio address over the British Broadcasting system a few weeks later. The speaker was the Assistant Director of the Observatory at Cambridge University (Dr. E. H. Linfoot):At the beginning of the century Young and Fresnal showed that the observed phenomena could be explained by supposing that light consisted of periodic trains of transverse waves similar to those in an elastic solid. During the next fifty years strenuous efforts were made to find out more about the nature of this hypothetical solid, which had been christened "the luminiferous ether." In consequence, the mathematical theory of elasticity made great strides, but the desired goal was not attained, and in fact the difficulties seemed to become more serious as knowledge increased. However, in 1860 Maxwell brought out his electromagnetic theory, in which light consists of electromagnetic vibrations of very short wavelength. This cut away the accumulated tangle of perplexities by removing the ether from the realm of ordinary solid matter altogether and putting it into a category by itself. Efforts to find out something about its true nature continued unabated, but with a growing suspicion that an essential point was being overlooked. This search led at the turn of the century to two unexpected discoveries, the second of which was nothing less than shattering.The first discovery (Dr. Linfoot said) was that a moving body does not communicate its motion to the ether which surrounds it, or even to the ether between its own particles, thus accentuating the distinction between ether and matter. The second discovery was that the velocity of light relative to the earth is the same whether or not the earth is moving relative to the ether. This contradiction of the observed change in the direction of the light coming from the fixed stars caused by the orbital motion of the earth, was only resolved in 1905 by the theory of relativity, "according to which the perceived space and time of one observer differ from that of another in motion relative to the first."
In Prof. Andrade's view, there is a scientific solution to the paradox of light behaving as a wave motion and as quanta:The solution of the paradox is that whenever we observe wave phenomena we are dealing with light energies that are equivalent to millions, or millions of millions, of particles. We can, then, regard the wave properties as expressing average behaviour or as expressing probabilities -- the likelihood that we shall find a large or a small number of particles at a given spot. The behaviour of a single particle we can never fully determine, a fact expressed in the so-called uncertainty principle.To a layman, this reconciliation would seem to be like life itself, full of uncertainties and probabilities, and to possess none of that assurance which we have been accustomed to believe is associated with the processes of scientific thought. We are forced to take refuge in what Prof. Andrade described as the essence of the uncertainty principle, "that the mere act of trying to determine the behaviour of an individual particle altered its behaviour." Verily, we are here in the realm of meta-physics.(London Times, February 18, 1950.)
In this impasse, it might be suggested that "To know what is light, and whether it is an actual substance or a mere undulation of the 'ethereal medium,' Science has first to learn what are in reality Matter, Atom, Ether, Force" (S.D. I, 482). Certainly, the arrival of the quantum theory devised by Planck in 1900, improved and elaborated as this has been by Einstein, Bohr, Heisenberg, and others, may be said to herald also the admission of the substantial nature of light, regarded as a force. And did not Sir William Crookes, in effect, weigh light with his invention of the radiometer in 1874, brought about by the heating of its vanes by light? Equally with Prof. Andrade, occultists do not deny the validity also of the vibratory theory: "Only they limit its functions to our Earth -- declaring its inadequacy on other planes than ours, since 'Masters' in the Occult Sciences perceive the CAUSES that produce ethereal vibrations" (S.D. I, 514). To determine fully the behaviour of a single particle, and to go beyond the average "probabilities" mentioned by Professor Andrade, it will be necessary to question more closely than has been done hitherto those postulates relating to the structure of matter and the nature of force which are the very foundation of the physical sciences. For the truth is that "Nearly three thousand years ago, earlier than the days of Pythagoras, the ancient philosophers claimed that light was ponderable -- hence matter, and that light was force" (Isis Unveiled, I, 281).
EXTENSIONS OF EVIDENCE
RADIO ASTRONOMY AND SUN-SPOTS
(Part 8 of an 11-part series)
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ONE (1) FOOTNOTE LISTED BELOW:
(1) NOTE.--H. P. Blavatsky took pains to extend the "theosophical view" as far into the literature, the culture, the science, and the scholarship of the time as impartial investigations in the various fields would permit. Students of Theosophy are therefore on the lookout for other corroborative testimony on be philosophy, as new avenues of thought open up among modern thinkers. "Extensions of Evidence" aims to scan common grounds whereon the theosophist may meet the mind of the race. The series began in the January, 1950, issue. --Editors THEOSOPHY.
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