Paul P. Mealing

Check out my book, ELVENE. Available as e-book and as paperback (print on demand, POD). 2 Reviews: here. Also this promotional Q&A on-line.

Friday, 30 December 2011

The Quantum Universe by Brian Cox and Jeff Forshaw

I’ve recently read this tome, subtitled Everything that can happen does happen, which is a phrase they reiterate throughout the book. Cox is best known as a TV science presenter for BBC. His series on the universe can be highly recommended. His youthful and conversational delivery, combined with an erudite knowledge of physics, makes him ideal for television. The same style comes across in the book despite the inherent difficulty of the topic.

In the last chapter, an epilogue, he mentions writing in September 2011, so this book really is hot off the press. Whilst the book is meant to cater for people with a non-scientific background, I’m unsure if it succeeds at that level and I’m not in a position to judge it on that basis. I’m fairly well read in this area, and I mainly bought it to see if they could add anything new to my knowledge and to compare their approach to other physics writers I’ve read.

They reference Richard Feynman (along with many other contributors to quantum theory) quite a lot, and, in particular, they borrow the same method of exposition that Feynman used in his book, QED. In fact, I’d recommend that this book be read in conjunction with Feynman’s book even though they overlap. Feynman introduced the notion of a one handed clock to represent the phase, amplitude and frequency of the wave function that lies at the heart of quantum mechanics (refer my post on Schrodinger’s equation, May 2011).

Cox and Forshaw use this same analogous method very effectively throughout the book, but they never tell the reader specifically that the clock represents the wave function as I assume it does. In fact, in one part of the book they refer to clocks and wave functions independently in the same passage, which could lead the reader to believe they are different things. If they are different things then I’ve misconstrued their meaning.

Early in their description of clocks they mention that the number of turns is dependent on the particle’s mass, thus energy. This is a direct consequence of Planck’s equation that relates energy to frequency, yet they don’t explain this. Later in the book, when they introduce Planck’s equation, they write it in terms of wavelength, not frequency, as it is normally expressed. These are minor quibbles, some might say petty, yet I believe they would help to relate the use of Feynman’s clocks to what the reader might already know of the subject.

One of the significant facts I learnt from their book was how Feynman exploited the ‘least action principle’ in quantum mechanics. (For a brief exposition of the least action principle refer my post on The Laws of Nature, Mar. 2008). Feynman also describes its significance in gravity in Six-Not-So-Easy Pieces: the principle dictates the path of a body in a gravitational field. In effect, the ‘least action’ is the difference between the kinetic and potential energy of the body. Nature contrives that it will always be a minimum, hence the description, ‘principle of least action’.

Now, I already knew that Feynman had applied it to quantum mechanics, but Cox and Forshaw provide us with the story behind it. Dirac had written a paper in 1933 entitled ‘The Lagrangian in Quantum Mechanics’ (the Lagrangian is the mathematical formulation of least action). In 1941, Herbet Jehle, a European physicist visiting Princeton, told Feynman about Dirac’s paper. The next day, Feynman found the paper in the Princeton library, and with Jehle looking on, derived Schrodinger’s equation in one afternoon using the least action principle. Feynman later told Dirac about his discovery, and was surprised to learn that Dirac had not made the connection himself.

But the other interesting point is that the units for ‘action’ in physics are mx2/t which are the same units as Planck’s constant, h. In other words, the fundamental unit of quantum mechanics is an ‘action’ unit. Now, units are important concepts in physics because only entities with the same type of units can be added and subtracted in an equation. Physicists talk about dimensions, because units must have the same dimensions to be able to be combined or deducted. The dimensions for ‘action’, for instance, are 1 of mass, 2 of length and -1 of time. To give a more common example, the dimensions for velocity are 0 of mass, 1 of length and -1 of time. You can add and subtract areas, for example, (2 dimensions of length) but you can’t add a length to an area or deduct an area from a volume (3 dimensions of length). Obviously, multiplication and calculus allow one to transform dimensions.

One of the concepts that Cox and Forshaw emphasise throughout the book is the universality of quantum mechanics and how literally everything is interconnected. They point out that no 2 electrons can have exactly the same energy, not only in the same atom but in the same universe (the Pauli Exclusion Principle). Also individual photons can never be tracked. In fact, they point out a little-known fact that Planck’s law is incompatible with the notion of tracking individual photons; a discovery made by Ladislas Natanson as far back as 1911. No, I’d never heard of him either, or his remarkable insight.

Cox and Forshaw do a brilliant job of explaining Wolfgang Pauli’s famous principle that makes individual atoms, and therefore matter, stable. They also expound on Freeman Dyson’s and Andrew Leonard’s 1967 paper demonstrating that it’s the Pauli Exclusion Principle that stops you from falling through the floor. Dyson described ‘the proof as extraordinarily complicated, difficult and opaque’, which may help to explain why it took so long for someone to derive it.

They also do an excellent job of explaining how quantum mechanics allows transistors to work, which is arguably the most significant invention of the 20th Century. In fact, it’s probably the best exposition I’ve come across outside a text book.

But what comes across throughout their book, is that the quantum world obeys specific ‘rules’ and once you understand those rules, no matter how bizarre they may seem to our common sense view of the world, you can make accurate and consistent predictions. The catch is that probability plays a key role and deterministic interpretations are not compatible with the quantum universe. In fact, Cox and Forshaw point out that quantum mechanics exhibits true ‘randomness’ unlike the ‘chaotic’ randomness that is dependent on ultra-sensitive initial conditions. In a recent issue of New Scientist, I came across someone discussing free will or the lack of it (in a book review on the topic) and espousing the view that everything is deterministic from the Big Bang onwards. Personally, I find it very difficult to hold such a philosophical position when the bedrock of the entire physical universe insists on chance.

Cox and Forshaw don’t have much to say about the philosophical implications of quantum mechanics except in one brief passage where they reveal a preference for the 'many worlds' interpretation because it does away with the so-called ‘collapse’ or ‘decoherence’ of the wave function. In fact, they make no reference to ‘collapse’ or ‘decoherence’ at all. They prefer the idea that there is an uninterrupted history of the quantum wave function, even if it implies that its future lies in another universe or a multitude of universes. But they also give tacit acknowledgement to Feynman’s dictum: ‘…the position taken by the “shut up and calculate” school of physics, which deftly dismisses any attempt to talk about the reality of things.’

In the epilogue, Cox and Forshaw get into some serious physics where they explain how quantum mechanics gives us the famous Chandrasekhar limit, developed by Subrahmanyan Chandresekhar in 1930, which determines how big a star can be before it becomes a neutron star or a black hole. The answer is 1.4 solar masses (1.4 times the mass of our sun). Mind you, it has to go through a whole series of phases in between and that’s what Cox and Forshaw explain, using some fundamental algebra along with some generous assumptions to make the exposition digestible for laypeople. But the purpose of the exercise is to demonstrate that quantum phenomena can determine limits on a stellar scale that have been verified by observation. It also gives a good demonstration of the scientific method in practice, as they point out.

This is a good book for introducing people to the mysteries of quantum mechanics with no attempt to side-step the inherent weirdness and no attempt to provide simplistic answers. They do their best to follow the Feynman tradition of telling it exactly as it is and eschew the magic that mysteries tend to induce. Nature doesn’t provide loop holes for specious reasoning. Quantum mechanics is the latest in a long line of nature’s secret workings, mathematically cogent and reliable, but deeply counter-intuitive.

Wednesday, 21 December 2011

The philosophy of Professor Sir Michael Marmot

This is another redoubtable interview by Margaret Throsby during her recent tour of Europe with the ACO (Australian Chamber Orchestra). Marmot holds a professorship at University College London and was President of the BMA (British Medical Association) until recently. As he admits in the interview, he was an unusual President in that he had an agenda.

The reason I’m writing a post about it is that he confirms a long-held belief of mine that the sense of having control of your life, or not, has an impact on your health, both psychological and physical. He quotes a German physician from the 19th Century, who apparently said: ‘physicians are the natural attorneys of the poor.’ This is because there is a ‘social gradient of health’ that exists in all Western societies (at least) and is not only unacknowledged but ignored. In other words, the poorer you are the poorer your health. According to Marmot, this gradient is statistically true right from the top to the bottom of our social hierarchy. And he puts it down to the sense of control one feels one has over one’s life. This outcome doesn’t surprise me, but apparently it surprises most other people, who think that the higher you are in the social train the more stress you are under and therefore the greater are your health risks. Marmot admits he thought this himself until he did the analysis and found the converse to be true.

Amongst other things, it makes a mockery of the health-reform debate in America, who seem determined to lag behind the rest of the Western world when it comes to social health issues.

In another interview by former Australian Prime Minister, Paul Keating, that touches on subjects like the lost opportunities at the end of the Cold War and politicians' propensity to not tell people the truth, he points out how real incomes in America have not increased over the last 20 years, which contributed to the subprime crisis. In America, corporations have a stranglehold on domestic politics, and no one sees the deleterious effect this has on the welfare of ordinary people.

This is a not unrelated side-issue to the fact that people, wherever they live, are deeply affected by living and working conditions that erode their sense of worth. We actually get the best out of people when they feel they have control over what they’re doing and are not just automatons. This means that the lower one is down the pecking order the less control one feels one has over one’s life and the greater the risk to their health and wellbeing. According to Marmot, figures from all over the Western world confirm this.

At the end of the interview he provides an interesting ‘statistic’. He contends that, globally, 100 billion people live in poverty and that 100 billion dollars could change that situation. This, of course, is a lot of money, but, to put it into perspective, 9 trillion dollars was spent to bail out the banks. It makes one wonder, when, and if, we will finally appreciate that promulgating the global poverty gap is not the way to proceed in the 21st Century.

P.S. I'm unsure how long these interviews are available.

Saturday, 17 December 2011

Consciousness Unexplained

The Mysterious Flame by Colin McGinn, subtitled Conscious Minds in a Material World, was recommended to my by The Atheist Missionary (aka TAM) almost 2 years ago, and it’s taken me all this time to get around to reading it.

But it was well worth the effort, and I can only endorse the recommendation given by The New York Times, as quoted on the cover: “There is no better introduction to the problem of consciousness than this.” McGinn is Professor of Philosophy at Rutgers University, with a handful of other books credited to him. Mysterious Flame was written in 1999, yet it’s not dated by other books I’ve read on this subject, and I would go so far as to say that anyone with an interest in the mind-body problem should read this book. Even if you don’t agree with him, I’m sure he has something to offer that you didn’t consider previously. At the end of the book, he also has something to say about the discipline of philosophy in general: its history and its unique position in human thought.

Most significantly, McGinn calls himself a ‘mysterian’, who is someone, like myself, as it turns out, who believes that consciousness is a mystery which we may never solve. Right from the start he addresses the two most common philosophical positions on this subject: materialism and dualism; demonstrating how they both fail. They are effectively polar opposite positions: materialism arguing that consciousness is neuronal activity full stop; and dualism arguing that consciousness is separate to the brain, albeit connected, and therefore can exist independently of the brain.

Materialism is the default position taken by scientists and dualism is the default position taken by most people even if they’re not aware of it. Most people think that ‘I’ is an entity that exists inside their head, dependent on their brain yet separate from it somehow. Many people, who have had out-of-body experiences, argue this confirms their belief. On the other hand, scientists have demonstrated how we can fool the ‘mind’ into thinking it is outside the body. I have argued elsewhere (Subjectivity, June 2009) that ‘I think’ is a tautology, because ‘I’ is your thoughts and nothing else.

McGinn acknowledges that consciousness is completely dependent on the brain but this alone doesn’t explain it. He points out that consciousness evolved relatively early in evolution and is not dependent on intelligence per se. Being more intelligent doesn’t make us more sentient than other species who also ‘feel’. He attacks the commonly held belief in the scientific community that consciousness just arises from this ‘meat’ we call a brain, and to create consciousness we merely have to duplicate this biological machine. I agree with him on this point. Not so recently (April 2011), I challenged an editorial and an article written in New Scientist inferring that sentience is an axiomatic consequence of artificial intelligence (AI): 'it’s just a matter of time before we will be forced to acknowledge it'. However, the biological evidence suggests that making AI more intelligent won’t create sentience, yet that’s exactly what most AI exponents believe. As McGinn says: ‘…sentience in general does not involve symbolic manipulation’, which is what a computer algorithm does.

McGinn argues that the problem with consciousness is that it’s non-spatial and therefore could exist in another dimension. This is not as daft as it sounds, because, as he points out, an additional dimension could exist without us knowing it and he references Edwin A. Abbott’s famous book, Flatland, to make his point. I’ve similarly argued that quantum mechanics could be explained by imagining a hidden dimension, so I’m not dismissive of this hypothesis.

The most important point that McGinn makes, in my opinion, is a fundamental one of epistemology. We humans tend to think that there is nothing that exists that is beyond our ultimate comprehension, yet there is no legitimate cognitive reason to assume that. To quote: ‘We should have the humility, and plain good sense, to admit that some things may exist without being knowable by us.’

This came up recently in an online discussion I had with Emanuel Rutten (Trying to define God, Nov. 11) who argued the opposite based on an ‘all possible worlds’ scenario. And if there were an infinite number of worlds, then Rutten’s argument would be valid. However, projecting what is possibly knowable in an infinite number of worlds to our specific world is epistemological nonsense.

As McGinn points out, most species on our planet can’t comprehend gravity or how the stars stay up in the sky or that the Earth goes around the sun – it’s beyond their cognitive abilities. Likewise there could be phenomena that are beyond our cognitive abilities, and consciousness may be one.

Roger Penrose addresses this epistemological point in Chapter 1 of Road to Reality, where he admits a ‘personal prejudice’ that everything in the natural world is within our cognitive grasp, whilst acknowledging that others don’t share his prejudice. In particular, Penrose contends that there is a Platonic mathematical realm, which is theoretically available to us without constraint (except the time to explore it), and that this Platonic realm can explain the entire physical universe. Interestingly, McGinn makes no reference to the significance of mathematics in determining the epistemological limit of our knowledge, yet I contend that this is a true limit.

Therefore, I would argue, based on this hypothetical mathematically cognitive limit, that if consciousness can’t be determined mathematically then it will remain a mystery.

Even though McGinn discusses amnesia in reference to the ‘self’, he doesn’t specifically address the fact that, without memory, there would be no ‘self’. Which is why none of us have a sense of self in our early infancy because we create no memories of it. It is memory that specifically gives us a sense of continuity of self and allows us to believe that the ‘I’ we perceive ourselves to be as an adult is the same ‘I’ we were as children.

I’ve skipped over quite a lot of McGinn’s book, obviously, but he does give arguably the best description of John Searle’s famous Chinese Room thought experiment I’ve read, without telling the reader that it is John Searle’s Chinese Room thought experiment.

At the end of the book, he devotes a short chapter to ‘The Unbearable Heaviness of Philosophy’ where he explains how ‘natural philosophy’ diverged from science yet they are more complementary than dichotomous. To quote McGinn again:

‘Science asks answerable questions… eliminating false theories, reducing the area of human ignorance, while philosophy seems mired in controversy, perpetually worrying at the same questions, not making the kind of progress characteristic of science.’

Many people perceive and present philosophy as the poor orphan of science in the modern age, yet I’m unsure if they will ever be completely separated or become independent. Science reveals that nature’s mysteries are endless and whilst those mysteries persist then philosophy will continue to play its role.

Right at the end of the book, McGinn makes a pertinent observation: that our DNA code contains the answer to our mystery, because consciousness is a consequence of the genetic instructions that make every sentient creature. So our genes have the information to create consciousness that consciousness itself is unable to comprehend.