Roger Penrose Quotes (1931-)

“What the anthropic principle depends upon is the idea that whatever is the nature of the universe, or universe portion that we see about us, being subject to whatever dynamical laws govern its actions, this must be strongly favourable to our very existence.”

“It's illegal to make superpositions with different vacua. That's one of the rules of quantum field theory.”

“The idea of having an ambient space-time of some specific dimension seems to play less of a role in string theory than in conventional physics, and certainly less than the kind of role that I would myself feel comfortable with. It is particularly difficult to assess the functional freedom that is involved in a physical theory unless one has a clear idea of its actual space-time dimensionality.”

“What right do we have to claim, as some might, that human beings are the only inhabitants of our planet blessed with an actual ability to be "aware"? [...] The impression of a "conscious presence" is indeed very strong with me when I look at a dog or a cat or, especially, when an ape or monkey at the zoo looks at me. I do not ask that they are "self-aware" in any strong sense (though I would guess that an element of self-awareness can be present). All I ask is that they sometimes simply feel!”

“I should begin by expressing my general attitude to present-day quantum theory, by which I mean standard non-relativistic quantum mechanics. The theory has, indeed, two powerful bodies of fact in its favour, and only one thing against it. First, in its favour are all the marvellous agreements that the theory has had with every experimental result to date. Second, and to me almost as important, it is a theory of astonishing and profound mathematical beauty. The one thing that can be said against it is that it makes absolutely no sense!”

“Moreover, the complete details of the complication of the structure of Mandelbrot's set cannot really be fully comprehended by anyone of us, nor can it be fully revealed by any computer. It would seem that this structure is not just part of our minds, but it has a reality of its own. ... The computer is being used in essentially the same way that the experimental physicist uses a piece of experimental apparatus to explore the structure of the physical world. '''The Mandelbrot set is not an invention of the human mind: it was a discovery. Like Mount Everest, the Mandelbrot set is just ''there'''''!”

“The Wick rotation idea is now so commonly used in quantum field theory that it is often taken as an automatic procedure in numerous different kinds of situation, with barely a mention, and its validity is hardly ever questioned. It does, in fact, have a broad applicability, but it is not a universally valid procedure. Most particularly. it is highly questionable in the context of the curved space-times arising in general relativity, when in normal circumstances the procedure cannot even be applied, because there is no natural time coordinate. In string theory, this is a problem both in the 10-dimensional space-time, in general curved-space situations, and also in the string world-sheet ...”

“How is it that mathematical ideas can be communicated in this way? I imagine that whenever the mind perceives a mathematical idea, it makes contact with Plato's world of mathematical concepts. ... When one 'sees' a mathematical truth, one's consciousness breaks through into this world of ideas, and makes direct contact with it ('accessible via the intellect'). I have described this 'seeing' in relation to Gödel's theorem, but it is the essence of mathematical understanding. When mathematicians communicate, this is made possible by each one having a direct route to truth, the consciousness of each being in a position to perceive mathematical truths directly, through this process of 'seeing'. (Indeed, often this act of perception is accompanied by words like 'Oh, I see'!) Since each can make contact with Plato's world directly, they can more readily communicate with each other than one might have expected. The mental images that each one has, when making this Platonic contact, might be rather different in each case, but communication is possible because each is directly in contact with the same externally existing Platonic world!”

“In my opinion, John Bell performed an extremely important role then, and also later, in generally supporting - thereby making respectable - the apparently "fringe" activities of such people as Karolyhazy, Bohm, [Philip M.] Pearle, Ghirardi, and many others (including myself) in suggesting schemes that go beyond standard quantum mechanics, in the intended direction of realism. No physicist could doubt the scientific credentials of John Bell. The fact that he was prepared to go out of his way to support research of this kind gave it a previously unaccustomed status.”

“Reading about the lives of geniuses can be a powerful antidote against any envy we might feel for not being among their number. Almost invariably they turn out not only to have had the same flaws, trials and heartbreaks as the rest of us but to be deeply weird to boot. The Nobel Prize-winning British physicist Roger Penrose certainly fits the template.”

“Although I'm regarded as a dangerous radical by particle physicists for proposing that there may be loss of quantum coherence, I'm definitely a conservative compared to Roger. I take the positivist viewpoint that a physical theory is just a mathematical model and that it is meaningless to ask whether it corresponds to reality. All that one can ask is that its predictions should be in agreement with observation. I think Roger is a Platonist at heart but he must answer for himself.”

“[I]n the June, 1960 issue of... the Annals of Physics, there appeared a paper by... Roger Penrose with the esoteric title "A Spinor Approach to General Relativity." Although the paper was highly mathematical, it outlined a very elegant and streamlined technique for solving certain problems in general relativity. ...this new method made some computations almost easy.”