The existence of the gravitational field is inseparably bound up with the existence of space.

According to the general theory of relativity space without ether is unthinkable ….

[I]t will be seen that I have not succeeded in formulating boundary conditions for spatial infinity. Nevertheless, there is still a possible way out …. For if it were possible to regard the universe as a continuum which is finite (closed) with respect to its spatial dimensions, we should have no need at all of any such boundary conditions.

I’m convinced more and more that the electrodynamics of moving bodies as it is presented today doesn’t correspond to reality. . .

Try and penetrate with our limited means the secrets of nature and you will find that, behind all the discernible concatenations, there remains something subtle, intangible and inexplicable

I would like to put the uncertainty principle in its historic place: When the revolutionary ideas of quantum physics were first coming out, people still tried to understand them in terms of old-fashioned ideas (such as, light goes in straight lines). … If you get rid of all the old-fashioned ideas and instead use … arrows for all the ways an event can happen there is no need for an uncertainty principle!