On Quantum Mechanics (Unsourced)

"For those who are not shocked when they first come across quantum theory cannot possibly have understood it." (Niels Bohr) 

"I hesitated to think it might be wrong, but I knew that it was rotten. That is to say, one has to find some decent way of expressing whatever truth there is in it." (John S. Bell) 

"[…] if one really understood the central point and its necessity in the construction of the world, one ought to be able to state it in one clear, simple sentence. Until we see the quantum principle with this simplicity we can well believe that we do not know the first thing about the universe, about ourselves, and about our place in the universe." (John A Wheeler)

"The mathematics of quantum mechanics is straightforward, but making the connection between the mathematics and an intuitive picture of the physical world is very hard." (Claude N. Cohen-Tannoudji)

"The world is not as real as we think. […] My personal opinion is that the world is even weirder than what quantum physics tells us." (Anton Zeilinger) 

"Those who are not shocked when they first come across quantum mechanics cannot possibly have understood it." (Niels Bohr)

"Our understanding of quantum mechanics is troubled by the problem of measurement and the problem of nonlocality. [...] It seems to me unlikely that either problem can be solved without a solution to the other, and therefore without a deep adjustment of space-time theory and quantum mechanics to each other." (Abner Shimony)

"String theory is extremely attractive because gravity is forced upon us. All known consistent string theories include gravity, so while gravity is impossible in quantum field theory as we have known it, it is obligatory in string theory." (Edward Witten)

"Quantum mechanics is the weirdest invention of mankind, but also one of the most beautiful. And the beauty of the mathematics underlying the quantum theory implies that we have found something very significant." (Anton Zeilinger)

"What you can show using physics, forces this universe to continue to exist. As long as you're using general relativity and quantum mechanics you are forced to conclude that God exists." (Frank Tipler)