Roger Penrose

The Road to Reality

"It has been a not uncommon view among confident theoreticians that we are 'almost there', and that a 'theory of everything' may lie not far beyond the subsequent developments of the late twentieth century. Often such comments had tended to be made with an eye on whatever had been the status fo the 'string theory' that had been current at the time. It is harder to maintain such a viewpoint now that string theory has transmogrified to something (M- or F-theory) who's nature is admitted to be fundamentally unknown at present."

"From my own perspective, we are much further from a 'final theory' even than this . . Various remarkable mathematical developments have indeed come out of string-theoretic (and related) ideas. However, I remain profoundly unconvinced that they are very much other than just striking pieces of mathematics albeit with input from some deep physical ideas. For theories whose space-time dimensionality exceeds what we directly observe (namely 1+3), I see no reason to believe that, in themselves, they carry us much further in the direction of physical understanding."

Radio Discussion with Alistair McGrath

Asked if science shows that the universe could 'create itself from nothing', Penrose replied "It's certainly not doing it yet. I think the book suffers rather more strongly than many. It's not an uncommon thing in popular descriptions of science to latch onto an idea, particularly things to do with string theory, which have absolutely no support from observation. They are just nice ideas."

M-theory is "very far from any testability .. It's a collection of ideas, hopes, aspirations."

About Grand Design "The book is a bit misleading. It gives you this impression of a theory that is going to explain everything; it's nothing of the sort. It's not even a theory."

About M-theory "it's hardly science."

Review of The Grand Design

"Among Einstein's difficulties with current quantum mechanics was its leading to subjective pictures of physical reality - as abhorrent to him as to me." "The same might apply to M-theory, but unlike quantum mechanics, M-theory enjoys no experimental support whatsoever."

Lennox in God and Stephen Hawking" p57ff quotes Penrose in a more lengthy manner.