The desire to find a material cause for all phenomena is instinctive in
the human mind, and has proved the chief impetus in a thousand
discoveries. And yet, unless we are on our guard, it is liable to be a
source of real error whenever we are dealing with the deeper problems of
thought. For when we have pushed our way into the inner sanctuary of any
department of nature, we almost invariably come upon a deep chasm that
we can pass over only by building a bridge of words. Some of these
verbal bridges have been decorated with very dignified names, such as
"the luminiferous ether," "gravity," "chemical affinity"; and when we
have shifted from the one side of the chasm to the other we impose upon
the credulity of the public (and even ourselves) by giving out the
impression that these words represent the real objective bridge on which
we crossed.
In how many ways do we by our theories dodge the crucial problem of how
energy is really transmitted, that is, how matter can act on distant
matter across seemingly vacant space. Gravity, and indeed all the forms
of the attractive forces, come under this head. True, we observe certain
regularities in the way in which these phenomena occur, and the
phenomenon at one place seems to be somehow dependent on some exercise
of force at another place. And so we invent an ingenious theory, and
fortify it all around with ponderous algebraic artillery for defense
against all attack. And by persistent use of such theories we hypnotize
ourselves into the belief that we are truly scientific in method, and
are dealing with objective realities, and that these learned theories
are something more than pretentious masks to hide our ignorance of real
nature; when in reality these theories seem to be only a material screen
to shield us from an embarrassing near view of the immediate action of
God in all the various phenomena of the world; for not many find it a
comfortable thought thus to live continuously beneath the great
Taskmaster's eye.
The theory of the luminiferous ether as the medium of the transmission
of light is one of these pretentious bridges of words. Our advancing
knowledge of electro-magnetic phenomena may some day drive us back to a
modified form of the corpuscular theory of light, and then we can throw
this of the ether to the winds. In that case we would at least have a
real material cause for the phenomena with which we deal. While the
current theory of the ether has so many inconsistencies, and attempts to
bridge over so many real chasms in our thinking that it seems truly
astonishing to see it taught so long. By the theory of the ether the
problems are not solved, they are merely postponed or evaded; for while
solving one difficulty it creates a multitude of its own. How then are
we better off than before without any such theory?
Being at liberty to invent any sort of qualities for their ether,
scientists have tried to imagine such a substance as they think they
need. The ether must be a kind of matter; but unlike any matter that we
know of it cannot have weight, or else it would gravitate together here
and there, thus becoming more abundant in some places than in others;
whereas the _need_ is for a material absolutely uniform throughout
space, even throughout the interiors of solid bodies, such as the earth
and the bodies upon the earth.
Another reason for supposing the ether to be a _plenum_, filling
absolutely all space, is that it must be perfectly frictionless; and for
this reason it cannot be composed of particles with spaces between them.
It must be frictionless, for otherwise the planets would be retarded in
their motions through space. The earth, for instance, is moving along
its orbit at the rate of eighteen miles a second; and yet the ether does
not pile up in front of it, nor is it made rarer in the wake of the
earth. Moreover, during the thousands of years during which astronomers
have been making observations absolutely no retardation has been
detected in the motions of the earth or of any of the heavenly bodies,
even to the smallest fraction of a second.
It is necessary to make the ether absolutely elastic and absolutely
rigid. We are acquainted with many materials that are elastic, and with
some that are comparatively rigid. But the elastic substances that we
are acquainted with are not rigid, and the rigid substances are not
elastic; and to assume such contradictory qualities in the ether
transports us far beyond the bounds of experimental science.
These are but a few of the difficulties raised by the assumption of the
ether as a real entity; but as there is no means of demonstrating its
existence, except by arguing the _necessity_ of having such a medium to
transmit radiant energy, it follows that no multiplication of objections
to the theory is likely to refute it in the minds of those who feel this
necessity. Those who refuse to admit the possibility of "action at a
distance," who insist on inventing a connecting material medium between
every observed effect and some material object with which it seems to be
in causal connection, will, I suppose, have to be allowed to exercise
their ingenuity in any way to satisfy their minds, even though they may
have to revise their theory with every fresh discovery in optics or
radioactivity.
There are many other ingenious mental devices, like this of the ether,
which seem to me only materialistic efforts to postpone or to dodge the
real vital lessons to be read from natural phenomena,--efforts to push
the real Cause back one step farther into the shadow,--a last desperate
effort, in the face of the constantly accumulating evidence of modern
knowledge that the great First Cause is far more intimately connected
with life and motion than many are willing to believe. We have already
mentioned gravity and the other attractive forces, such as cohesion and
adhesion; but seemingly very few people have ever paused to consider how
utterly inexplicable they still remain in any physical or materialistic
sense.
It is easy to explain any form of a _push_ in a physical way; but
gravity is _not a push but a pull_. And how are we to explain the method
by which a body can act where it is not, how explain in detail the way
by which it can reach out and pull in toward itself another separated
body, and exert this pull across the immeasurably wide fields of space?
The law of inverse squares may tell us very accurately the manner in
which the results are accomplished, for our Creator is a God of order.
But there is no materialistic theory of the _why_ of gravitation that is
worth employing the time of sensible, truth-loving people. And we can
rest assured that there never will be any such real "explanation," save
that this is the way which the great Jehovah has ordained. Since such
theories only explain the known in terms of the unknown, they can serve
only as a sort of mental buffer or shield between us and the conception
of the direct working of a personal God, whose word must always be as
effective throughout the remotest corners of His universe as near at
hand, for the very simple reason that matter has no "properties" which
He has not imparted to it, and accordingly it can have no innate inertia
or reluctance to act which God's word would need to overcome in order to
induce it to act, even when this word operates across the wide fields
of space. On this explanation these phenomena of "action at a distance"
are at least intelligible; while to me, and I speak now as a scientist,
they are intelligible in no other way.