Definitive Quote by Kip Thorne

“Problem 1: Combine general relativity and quantum theory into a single theory that can claim to be the complete theory of nature. This is…

— Lee Smolin

“Now, at the outset of the twenty-first century, we stand on the verge of a new revolution. The search for a deeper theory than…

— Marcus Chown

The quest for a quantum gravity is one of the greatest unsolved problems in all of science.

— Michio Kaku

Quantum mechanics as it stands would be perfect if we didn’t have the quantum-gravity issue and a few other very deep fundamental problems.

— Gerard 't Hooft

I do feel strongly that string theory is our best hope for making progress at unifying gravity and quantum mechanics.

— Brian Greene

The extreme weakness of quantum gravitational effects now poses some philosophical problems; maybe nature is trying to tell us something new here: maybe we…

— Richard P. Feynman

One of the main successes of string theory is that it has been able to unify the general theory of relativity, which describes gravity,…

— Ashoke Sen

I am not aware of any sensible theory of how classical gravity could interact with quantum matter, and I can't imagine how such a…

— Alan Guth

“The loop approach to quantum gravity is now a thriving field of research. Many of the older ideas, such as supergravity and the study…

— Lee Smolin

I came to realise that string theory offers us the best hope of finding a unified theory of all matter and forces.

— Ashoke Sen

“The key question for a quantum theory of gravity is then the following: Can we extend to quantum theory the principle that space has…

— Lee Smolin

“So the challenge for any quantum theory of gravity is to give us a deeper understanding of Bekenstein's entropy and Hawking's temperature.”

— Lee Smolin