Theory of relativity

No mathematician can give any meaning to the language about matter, force, inertia used in current text-books of mechanics.

— Theory of relativity

The modern theory of relativity, on its mathematical side, is merely an elaboration of Riemann's analysis.

— Theory of relativity

If you don't take my words too seriously, I would say this: If we assume that all matter would disappear from the world, then, before relativity, one believed that space and time would continue existing in an empty world. But, according to the theory of relativity, if matter and its motion disappeared there would no longer be any space or time.

— Theory of relativity

One clock stayed on the ground; its double flew. / And it ran slow. So, then. The mad thing's true.

— Theory of relativity

I consider the theory of relativity to be an example showing how a fundamental scientific discovery, sometimes even against the resistance of its creator, gives birth to further fruitful developments, following its own autonomous course.

— Theory of relativity

Einstein's famous theory of relativity states that while phenomena appear different to someone close to a black hole, traveling close to the speed of light, or in a falling elevator here on earth, scientists in profoundly different environments will nevertheless always discover the same underlying laws of nature.

— Theory of relativity

There is another side to the theory of relativity. ...the development of science is in the direction to make it less subjective, to separate more and more in the observed facts that which belongs to the reality behind the phenomena, the absolute, from the subjective element, which is introduced by the observer, the relative. Einstein's theory is a great step in that direction. We can say that the theory of relativity is intended to remove entirely the relative and exhibit the pure absolute.

— Theory of relativity

It did not last: the Devil howling 'Ho!Let Einstein be!' restored the status quo.

— Theory of relativity

Einstein's theory of relativity has advanced our ideas of the structure of the cosmos a step further. It is as if a wall which separated us from Truth has collapsed. Wider expanses and greater depths are now exposed to the searching eye of knowledge, regions of which we had not even a presentiment. It has brought us much nearer to grasping the plan that underlies all physical happening.

— Theory of relativity

If our world-line and that of the body which is being observed are parallel, the body is said to be at rest. But if the two world-lines are not parallel, then, when interpreting things in terms of space and time, the body will be said to be in relative motion.

— Theory of relativity