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EINSTEIN'S THEORIES OF RELATIVITY AND GRAVITATION
A SELECTION OF MATERIAL FROM THE ESSAYS
SUBMITTED IN THE COMPETITION
FOR THE EUGENE HIGGINS PRIZE OF $5,000
COMPILED AND EDITED,
AND INTRODUCTORY MATTER SUPPLIED
BY
J. MALCOLM BIRD,
Associate Editor, Scientific American
NEW YORK
SCIENTIFIC AMERICAN PUBLISHING CO.,
MUNN & CO.
1921
PREFACE
The obstacles which the layman finds to understanding Einstein's
relativity theories lie not so much in the inherent difficulty of
these theories themselves as in the difficulty of preparing the
mind for their reception. The theory is no more difficult than any
scientific development of comparable depth; it is not so difficult as
some of these. But it is a fact that for a decent understanding of it,
a large background of scientific knowledge and scientific habit of
thought is essential. The bulk of the writers who have attempted to
explain Einstein to the general reader have not realized the great gulf
which lies between the mental processes of the trained mathematician
and those of the man in the street. They have not perceived that
the lay reader must be personally conducted for a long distance from
the vestibule of the temple of science before he comes to Einstein,
and that he cannot by any possibility make this journey unaided. The
result has been to pitchfork the reader into the intricacies of the
subject without adequate preparation.
The present volume avoids this mistake with the utmost care. It avoids
it, in fact, with such deliberation as to make it in order to say a
word in explanation of what will at first glance seem an extraordinary
arrangement of material. It was to be expected, doubtless, that this
book would open with a brief statement of the genesis and the outcome
of the Einstein Prize Essay Contest for the $5,000 prize offered by
Mr. Eugene Higgins. It was doubtless to be expected that, after this
had been dismissed, the winning essay would be given the post of honor
in advance of all other material bearing actually on the Einstein
theories. When the reader observes that this has not been done, he
will by all means expect a word of explanation; and it is mainly for
the purpose of giving this that we make these introductory remarks.
The essays submitted in the contest, and in particular the comments of
a few disappointed readers upon Mr. Bolton's prize essay, make quite
plain what might have been anticipated--that in the small compass
of 3,000 words it is not possible both to prepare the reader's mind
for a discussion of Relativity and to give a discussion that shall be
adequate. Mr. Bolton himself, in replying to a protest that he had not
done all this, has used the word "miracle"--we think it a well-advised
one. No miracle was expected as a result of the contest, and none has
been achieved. But in awarding the prize, the Judges had to decide
whether it was the best preliminary exposition or the best discussion
that was wanted. They decided, and rightly we believe, that the award
should go to an actual statement of what the Einstein theories are
and what they do, rather than to a mere introduction, however well
conceived and well executed the latter might be. Nevertheless,
we should be closing our eyes to a very obvious fact if we did
not recognize that, without something in the way of preparation,
the general reader is not going to pursue Mr. Bolton's essay, or
any other essay on this subject, with profit. It is in order the
more forcefully to hold out inducements to him to subject himself to
this preparation that we place at the head of the book the chapters
designed to give it to him.
Chapter II. is intended so to bring the mind of the reader into contact
with certain philosophical problems presented to us by our experiences
with the external world and our efforts to learn the facts about it,
that he may approach the subject of relativity with an appreciation
of the place it occupies as a phase of human thought and a pillar of
the scientific structure. Until the reader is aware of the existence
of these problems and the directions taken by the efforts, successful
and unsuccessful, to unravel them, he is not equipped to comprehend
the doctrine of relativity at all; he is in much the same case as a
child whose education had reached only the primer stage, if asked to
read the masterpieces of literature. He lacks not alone the vocabulary,
but equally the mental background on which the vocabulary is based.
It will be noted that in this and the chapters immediately following
it, the Editor has supplied material freely. The obvious interpretation
is that satisfactory material covering the desired ground was not
found in any of the essays; for we are sure the scope and number
of the credited excerpts will make it clear that all contributions
were adequately scrutinized in search of available passages. This
"inadequacy" of the competing essays has been severely commented
upon by several correspondents, and the inference drawn that as
a whole the offerings were not up to the mark. Such a viewpoint
is wholly unjust to the contestants. The essays which paid serious
attention to the business of paving the way to relativity necessarily
did so at the expense of completeness in the later paragraphs where
specific explanation of the Einstein theories was in order. Mr. Law,
whose essay was by all means the best of those that gave much space
to introductory remarks, found himself left with only 600 words
in which to tell what it was that he had been introducing. The
majority of the contestants appear to have faced the same question
as to subject matter which the Judges faced, and to have reached
the same decision. They accordingly devoted their attention toward
the prize, rather than toward the production of an essay that would
best supplement that of the winner. It is for this very reason that,
in these preliminary chapters, so large a proportion of the material
has had to be supplied by the Editor; and this very circumstance is
a tribute to the good judgment of the competitors, rather than ground
for criticism of their work.
The general introduction of Chapter II. out of the way, Chapters
III. and IV. take up the business of leading the reader into the
actual subject of relativity. The subject is here developed in what
may be called the historical order--the order in which it took form in
Einstein's own mind. Both in and outside the contest of which this book
is the outcome, a majority of those who have written on relativity
have followed this order, which is indeed a very natural one and
one well calculated to give to the rather surprising assumptions of
relativity a reasonableness which they might well appear to the lay
mind to lack if laid down more arbitrarily. In these two chapters
no effort is made to carry the argument beyond the formulation of
the Special Principle of the relativity of uniform motion, but this
principle is developed in considerably more detail than would be the
case if it were left entirely to the competing essayists. The reason
for this is again that we are dealing with a phase of the subject
which is of subordinate importance so far as a complete statement of
the General Theory of Relativity is concerned, but which is of the
greatest significance in connection with the effort of the layman to
acquire the proper preliminary orientation toward the larger subject.