The problem of how to make a theory of a whole universe is thus the problem of how to construct a theory without making any reference to anything that exists … outside of the system we are describing.

No matter how smart she is, no matter how modern her methods and how tricky her reasoning, a detective cannot be a good detective unless in the end the bad guys are found out. It is the same with science.

At present … the question of what happens inside of a black hole when quantum effects are taken into account remains unresolved.

In science, detective movies, love or any other area of life, when one is confronted with a situation in which the old assumptions are no longer working as they used to, it is perhaps time to look for new questions to ask.

[T]he ether … is now redundant…. In the absence of radiation and ponderable matter there is no substance, there is empty space.

That he may have missed the target in his speculations, as, for example, in his hypothesis of light quanta, cannot really be held too much against him, for it is not possible to introduce really new ideas even in the most exact science without sometimes taking a risk.

[T]he origin of inertia is and remains the most obscure subject in the theory of particles and fields.

Today an individual galaxy is considered as a local disturbance of a distribution which is indeed isotropic and homogeneous, to a degree which itself demands explanation. Einstein had no such physical grounds for assuming these two properties ….

That fellow Einstein suits his convenience. Every year he retracts what he wrote the year before.