Relativity: The Special & the General Theory: A Popular Exposition, 3rd Ed.

“Dear Habicht, / Such a solemn air of silence has descended between us that I almost feel as if I am committing a sacrilege when I break it now with some inconsequential babble... / What are you up to, you frozen whale, you smoked, dried, canned piece of soul...?””

— Albert Einstein

“If you've never done anything wrong it's probably because you have never tried anything new.””

— Albert Einstein

“Silence is the hardest scream””

— Albert Einstein

“result: every description of events in space involves the use of a rigid body to which such events have to be referred. The resulting relationship takes for granted that the laws of Euclidean geometry hold for ‘distances’, the ‘distance’ being represented physically by means of the convention of two marks on a rigid body.””

— Albert Einstein

“The struggle, so violent in the early days of science, between the views of Ptolemy and Copernicus would then be quite meaningless. Either CS [coordinate system] could be used with equal justification. The two sentences, “the Sun is at rest and the Earth moves,” or “the Sun moves and the Earth is at rest,” would simply mean two different conventions concerning two different CS.””

— Albert Einstein

“if, relative to K, K’ is a uniformly moving co-ordinate system devoid of rotation, then natural phenomena run their course with respect to K’ according to exactly the same general laws as with respect to K. This statement is called the Principle of Relativity (in the restricted sense).””

— Albert Einstein

“Fundamental ideas play the most essential role in forming a physical theory. Books on physics are full of complicated mathematical formulae. But thought and ideas, not formulae, are the beginning of every physical theory.””

— Albert Einstein

“of the actual objects of physical reality. Physical objects are not in space, but these objects are spatially extended.””

— Albert Einstein

“He might also interpret his experience thus: “My body of reference (the carriage) remains permanently at rest. With reference to it, however, there exists (during the period of application of the brakes) a gravitational field which is directed forwards and which is variable with respect to time. Under the influence of this field, the embankment together with the earth move non-uniformly in such a manner that their original velocity in the backward direction is continuously reduced.””

— Albert Einstein