"It is possible to build a virtual-reality generator whose repertoire includes every possible environment."

"Time travel may be achieved one day, or it may not. But if it is, it should not require any fundamental change in world-view, at least for those who broadly share the world view I am presenting in this book."

"I myself believe that there will one day be time travel because when we find that something isn't forbidden by the over-arching laws of physics we usually eventually find a technological way of doing it."

"The overwhelming majority of theories are rejected because they contain bad explanations, not because they fail experimental tests."

"Is the human race a universal constructor?"

"Quantum computation is... a distinctively new way of harnessing nature... It will be the first technology that allows useful tasks to be performed in collaboration between parallel universes."

"The truly privileged theories are not the ones referring to any particular scale of size or complexity, nor the ones situated at any particular level of the predictive hierarchy, but the ones that contain the deepest explanations."

"Our best theories are not only truer than common sense, they make more sense than common sense."