In 1925, the philosopher Bertrand Russell wrote a four-part series in The Nation explaining “The A B C of Relativity,” teasing out the implications of the theory of relativity as developed by Albert Einstein, born 136 years ago today.
It is generally recognized by the public that Einstein has done something astonishing, has in some way revolutionized our conception of the physical world. But what he has done is so wrapped up in mathematical technicalities that it is almost impossible for non-mathematicians to make out its import from the accounts of specialists, while popular accounts usually suggest ideas which are not wholly correct. For this, the word relativity is partly to blame. People often imagine that the new theory proves everything to be relative, whereas, on the contrary, it is wholly concerned to exclude what is relative and arrive at a statement of physical laws that shall in no way depend upon the circumstances of the observer. It is true that these circumstances have been found to have more effect upon what appears than they were formerly thought to have, but at the same time Einstein showed how to discount this effect completely. This was the source of almost everything that is surprising in his theory.
