Einstein: On the Principle of Relativity

What is the Special Principle of Relativity?

This short article is one of the very first scientific essays written by Einstein intended for the general, non-scientist, audience. It was originally written, in 1914, for the readers of one of the most widely-read newspapers in Germany at the time.

Einstein published his two seminal papers on special relativity in 1905, and his work was gradually being recognized. In 1913, Max Planck and Walther Nernst made a trip to Zurich, where Einstein had been mostly living throughout his young adult life, to recruit Einstein (back) to Germany, which he agreed to. It was a triumphant return for Einstein. This article was published to celebrate this occasion, and his newly-earned prestige.

Special relativity is based on the special principle of relativity, or simply the principle of relativity. This short newspaper article (~5 pages) explains what the principle of relativity is, at a very high level, and what kind of general interesting phenomena are predicted from the theory. The predictions of special relativity have all been confirmed, without exceptions.

As for general relativity, he ended up completing his field equations of gravity at the end of 1915, and this article briefly describes why the generalization was necessary.

This article was originally written by Einstein in German, and it is now in the public domain. This short booklet attempts at a new translation to give a somewhat clearer account of what Einstein wanted to convey in his original writing.

A completely new English translation - 2024!

Note: This article, "On the Principle of Relativity", by Einstein and the Translator's notes are also included in the book, "Einstein's Seven Essays on Relativity, Geometry, and Scientific Methods" (2025).