THE A B C OF RELATIVITY BY BERTRAND RUSSELL AUTHOR OF "THE PRINCIPLES OF MATHEMATICS "PROPOSED ROADS TO FREEDOM" PUBLISHERS HARPER & BROTHERS NEW YORK AND LONDON THE A B C OF RELATIVITY Copyright, 1925, by Harper & Brothers Printed in the United States of America B-A THE ABC OF RELATIVITY E VERYBODY knows that Einstein has done something astonishing, but very few people know exactly what it is that he has done. It is generally recognized that he has revolutionized our conception of the physical world, but his new conceptions are wrapped up in mathematical technicalities. It is true that there are innumerable popular accounts of the theory of relativity, but they generally cease to be intelligible just at the point where they begin to say something important. The authors are hardly to blame for this. Many of the new ideas can be expressed in non-mathematical language, but they are none the less difficult on that account. What is demanded is a change in our imaginative picture of the world-a picture which has been handed down from remote, perhaps pre-human, I |