Roger Penrose: Physics

“It seems to me that we must make a distinction between what is "objective" and what is "measurable" in discussing the question of physical reality, according to quantum mechanics.”

Roger Penrose book The Emperor's New Mind

Source: The Emperor's New Mind (1989), Ch. 6, Quantum Magic and Quantum Mastery, p. 269.
Context: It seems to me that we must make a distinction between what is "objective" and what is "measurable" in discussing the question of physical reality, according to quantum mechanics. The state-vector of a system is, indeed, not measurable, in the sense that one cannot ascertain, by experiments performed on the system, precisely (up to proportionality) what the state is; but the state-vector does seem to be (again up to proportionality) a completely objective property of the system, being completely characterized by the results it must give to experiments that one might perform.

Question , Reality

“How relevant, indeed, is our present lack of understanding of physics at the quantum/classical boundary? Or is consciousness really “no big deal,” as has sometimes been expressed?
It would be too optimistic to expect to find definitive answers to all these questions, at our present state of knowledge, but there is much scope for healthy debate…”

Roger Penrose

Foreword (March 2007) to Quantum Aspects of Life (2008), by Derek Abbott.
Context: Does life in some way make use of the potentiality for vast quantum superpositions, as would be required for serious quantum computation? How important are the quantum aspects of DNA molecules? Are cellular microtubules performing some essential quantum roles? Are the subtleties of quantum field theory important to biology? Shall we gain needed insights from the study of quantum toy models? Do we really need to move forward to radical new theories of physical reality, as I myself believe, before the more subtle issues of biology — most importantly conscious mentality — can be understood in physical terms? How relevant, indeed, is our present lack of understanding of physics at the quantum/classical boundary? Or is consciousness really “no big deal,” as has sometimes been expressed?
It would be too optimistic to expect to find definitive answers to all these questions, at our present state of knowledge, but there is much scope for healthy debate...

Understanding , Question , Knowledge

“General relativity is certainly a very beautiful theory, but how does one judge the elegance of physical theories generally?”

Roger Penrose book Fashion, Faith, and Fantasy in the New Physics of the Universe

Ch. 1, Mathematical Elegance as a Driving Force, p. 7 https://books.google.com/books?id=T09kCwAAQBAJ&pg=PA7.
Fashion, Faith, and Fantasy in the New Physics of the Universe (2016)

Beauty

“Whereas originally the hopes for string theory, and its descendants, were that some kind of uniqueness would be arrived at, whereby the theory would supply mathematical explanations for the measured numbers of experimental physics, the string theorists were driven to find refugee in the strong anthropic argument in an attempt to narrow down an absolutely vast number of alternatives. In my own view, this a very sad and unhelpful place for a theory to find itself.”

Roger Penrose book Fashion, Faith, and Fantasy in the New Physics of the Universe

Source: Fashion, Faith, and Fantasy in the New Physics of the Universe (2016), Ch. 3 Fantasy, p 322

Sadness , Hope , Mathematics , Strong

“The idea of having an ambient space-time of some specific dimension seems to play less of a role of 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.”

Roger Penrose book Fashion, Faith, and Fantasy in the New Physics of the Universe

Ch. 1, Mathematical Elegance as a Driving Force, p. 62 https://books.google.com/books?id=T09kCwAAQBAJ&pg=PA62.
Fashion, Faith, and Fantasy in the New Physics of the Universe (2016)

Feeling , Idea , Freedom , Time