Archive for August, 2012

Ablution

Posted in Jazz with tags , , , , , on August 26, 2012 by telescoper

I haven’t posted any jazzy bits for a while. I don’t know why. Anyway, I just found this track, called Ablution, by alto saxophonist Lee Konitz . Unless my ears deceive me the pianist on this track is Ronnie Ball (British, by the way) whose comping  makes no attempt to disguise the fact that it is a variation on the famous Jerome Kern tune All The Things You Are, the unusual chords of which have made it a popular vehicle for jazz musicians to improvise on ever since it was written back in 1939. In the bebop era it was typical practice to base original compositions on top of the chord sequences of standard tunes, and this is a prime example although I don’t know in this case whether Lee Konitz managed to get away without paying composer’s royalties!

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English Language O Level, Vintage 1979

Posted in Education with tags , , , , , , on August 26, 2012 by telescoper

Judging by the furore surrounding the last-minute marking down of GCSE English Language examinations this year, I thought it might be interesting to put the old scanner to work and show you the English Language examinations I took at age 16, way back in 1979. In those days the GCSE hadn’t been invented yet, and instead we had two different systems GCE  O Level (which I took) and CSE. Anyway, these be the papers what I sat.

The one thing that surprises me a little in retrospect is the considerable emphasis on poetry in the second paper, which I now think would belong more in an English Literature paper. However, there’s no doubt that my schooldays instilled in me a lifelong love of poetry and for that I won’t complain at all…

I’d be very interested in any comments about the difference in style and content between these and modern-day GCSE English Language.

P.S. If you’re wondering what happened to Page 2 of Paper 1, it’s completely blank so I didn’t scan it.

A Hero of Our Time

Posted in The Universe and Stuff with tags on August 25, 2012 by telescoper

R.I.P. Neil Armstrong (August 5, 1930 – August 25, 2012)

The Sound of Hammer Horror

Posted in Film, Music, Opera with tags , , , , , on August 25, 2012 by telescoper

I’ve been meaning for a while to post a little tribute to British composer James Bernard, and this Bank Holiday Weekend has left me with a bit of time to do so now. Most of you are probably wondering who James Bernard is (or was; he died in 2001), but many of you will have heard his music many times without realising it, for he was the composer who wrote most of the music for the classic British horror movies made by Hammer Film Productions from the late 1950s through to the 1970s.

I’m by no means an aficionado of horror films – or films of any sort for that matter, as I rarely go to the cinema these days – but I do enjoy the opera, which is probably why I find these films so interesting. I don’t think they would have established themselves as the classics there without the unique atmosphere conjured up by James Bernard’s scores. Nor without such fine actors as Christopher Lee and Peter Cushing, of course. The reason for this is that’s not much in these films in terms of purely visual horror – they work so well by creating an undertone of dread and impending terror so that the viewers’ own imaginations frighten them more than what’s shown on the screen. Viewed without the music, most of these films look pretty tame although I have to say I think The Devil Rides Out would have had me hiding behind the sofa even without the music!

Here is a little taste of what is probably his most famous score, for The Horror of Dracula (1958) which starred the inimitable Christopher Lee in the title role.

I think there are two things worth mentioning about this particular piece. The first is that the main theme is built around a three-note motif inspired by the three syllables of the name “Dra-cu-la”. Even more interestingly, Bernard doubles that line in the orchestra a whole tone higher, the resulting clash of harmonies producing that jarring sound that ratchets up the psychological tension. It’s a simple device, but remarkably effective, especially when combined with the unusual percussion.

The second thing that struck me listening to this just now is how reminiscent the entry of the high strings (about 0:49) is of the orchestration of the sea interludes from Benjamin Britten’s opera Peter Grimes. That’s not a surprise at all, because James Bernard was a childhood friend of Britten, and they worked together at various times in later life. Bernard’s music is often atonal and sometimes puts me in mind of Britten’s gripping opera A Turn of the Screw, based on the famous ghost story by Henry James, which also uses atonal techniques to produce an unsettling musical undercurrent. Alban Berg’s opera Lulu (a performance of which I reviewed here) also springs to mind as one in which the lack of a tonal centre in the music produces an atmosphere of disorientation and inner dread.

Pathways to Research

Posted in Education, The Universe and Stuff with tags , , , , , on August 24, 2012 by telescoper

The other day I had a slight disagreement with a colleague of mine about the best advice to give to new PhD students about how to tackle their research. Talking to a few other members of staff about it subsequently has convinced me that there isn’t really a consensus about it and it might therefore be worth a quick post to see what others think.

Basically the issue is whether a new research student should try to get into “hands-on” research as soon as he or she starts, or whether it’s better to spend most of the initial phase in preparation: reading all the literature, learning the techniques required, taking advanced theory courses, and so on. I know that there’s usually a mixture of these two approaches, and it will vary hugely from one discipline to another, and especially between theory and experiment, but the question is which one do you think should dominate early on?

My view of this is coloured by my own experience as a PhD (or rather DPhil student) twenty-five years ago. I went directly from a three-year undergraduate degree to a three-year postgraduate degree. I did a little bit of background reading over the summer before I started graduate studies, but basically went straight into trying to solve a problem my supervisor gave me when I arrived at Sussex to start my DPhil. I had to learn quite a lot of stuff as I went along in order to get on, which I did in a way that wasn’t at all systematic.

Fortunately I did manage to crack the problem I was given, with the consequence that got a publication out quite early during my thesis period. Looking back on it I even think that I was helped by the fact that I was too ignorant to realise how difficult more expert people thought the problem was. I didn’t know enough to be frightened. That’s the drawback with the approach of reading everything about a field before you have a go yourself…

In the case of the problem I had to solve, which was actually more to do with applied probability theory than physics, I managed to find (pretty much by guesswork) a cute mathematical trick that turned out to finesse the difficult parts of the calculation I had to do. I really don’t think I would have had the nerve to try such a trick if I had read all the difficult technical literature on the subject.

So I definitely benefited from the approach of diving headlong straight into the detail, but I’m very aware that it’s difficult to argue from the particular to the general. Clearly research students need to do some groundwork; they have to acquire a toolbox of some sort and know enough about the field to understand what’s worth doing. But what I’m saying is that sometimes you can know too much. All that literature can weigh you down so much that it actually stifles rather than nurtures your ability to do research. But then complete ignorance is no good either. How do you judge the right balance?

I’d be interested in comments on this, especially to what extent it is an issue in fields other than astrophysics.

The Return of the Inductive Detective

Posted in Bad Statistics, Literature, The Universe and Stuff with tags , , , , , , , , on August 23, 2012 by telescoper

A few days ago an article appeared on the BBC website that discussed the enduring appeal of Sherlock Holmes and related this to the processes involved in solving puzzles. That piece makes a number of points I’ve made before, so I thought I’d update and recycle my previous post on that theme. The main reason for doing so is that it gives me yet another chance to pay homage to the brilliant Jeremy Brett who, in my opinion, is unsurpassed in the role of Sherlock Holmes. It also allows me to return to a philosophical theme I visited earlier this week.

One of the  things that fascinates me about detective stories (of which I am an avid reader) is how often they use the word “deduction” to describe the logical methods involved in solving a crime. As a matter of fact, what Holmes generally uses is not really deduction at all, but inference (a process which is predominantly inductive).

In deductive reasoning, one tries to tease out the logical consequences of a premise; the resulting conclusions are, generally speaking, more specific than the premise. “If these are the general rules, what are the consequences for this particular situation?” is the kind of question one can answer using deduction.

The kind of reasoning of reasoning Holmes employs, however, is essentially opposite to this. The  question being answered is of the form: “From a particular set of observations, what can we infer about the more general circumstances that relating to them?”.

And for a dramatic illustration of the process of inference, you can see it acted out by the great Jeremy Brett in the first four minutes or so of this clip from the classic Granada TV adaptation of The Hound of the Baskervilles:

I think it’s pretty clear in this case that what’s going on here is a process of inference (i.e. inductive rather than deductive reasoning). It’s also pretty clear, at least to me, that Jeremy Brett’s acting in that scene is utterly superb.

I’m probably labouring the distinction between induction and deduction, but the main purpose doing so is that a great deal of science is fundamentally inferential and, as a consequence, it entails dealing with inferences (or guesses or conjectures) that are inherently uncertain as to their application to real facts. Dealing with these uncertain aspects requires a more general kind of logic than the  simple Boolean form employed in deductive reasoning. This side of the scientific method is sadly neglected in most approaches to science education.

In physics, the attitude is usually to establish the rules (“the laws of physics”) as axioms (though perhaps giving some experimental justification). Students are then taught to solve problems which generally involve working out particular consequences of these laws. This is all deductive. I’ve got nothing against this as it is what a great deal of theoretical research in physics is actually like, it forms an essential part of the training of an physicist.

However, one of the aims of physics – especially fundamental physics – is to try to establish what the laws of nature actually are from observations of particular outcomes. It would be simplistic to say that this was entirely inductive in character. Sometimes deduction plays an important role in scientific discoveries. For example,  Albert Einstein deduced his Special Theory of Relativity from a postulate that the speed of light was constant for all observers in uniform relative motion. However, the motivation for this entire chain of reasoning arose from previous studies of eletromagnetism which involved a complicated interplay between experiment and theory that eventually led to Maxwell’s equations. Deduction and induction are both involved at some level in a kind of dialectical relationship.

The synthesis of the two approaches requires an evaluation of the evidence the data provides concerning the different theories. This evidence is rarely conclusive, so  a wider range of logical possibilities than “true” or “false” needs to be accommodated. Fortunately, there is a quantitative and logically rigorous way of doing this. It is called Bayesian probability. In this way of reasoning,  the probability (a number between 0 and 1 attached to a hypothesis, model, or anything that can be described as a logical proposition of some sort) represents the extent to which a given set of data supports the given hypothesis.  The calculus of probabilities only reduces to Boolean algebra when the probabilities of all hypothesese involved are either unity (certainly true) or zero (certainly false). In between “true” and “false” there are varying degrees of “uncertain” represented by a number between 0 and 1, i.e. the probability.

Overlooking the importance of inductive reasoning has led to numerous pathological developments that have hindered the growth of science. One example is the widespread and remarkably naive devotion that many scientists have towards the philosophy of the anti-inductivist Karl Popper; his doctrine of falsifiability has led to an unhealthy neglect of  an essential fact of probabilistic reasoning, namely that data can make theories more probable. More generally, the rise of the empiricist philosophical tradition that stems from David Hume (another anti-inductivist) spawned the frequentist conception of probability, with its regrettable legacy of confusion and irrationality.

In fact Sherlock Holmes himself explicitly recognizes the importance of inference and rejects the one-sided doctrine of falsification. Here he is in The Adventure of the Cardboard Box (the emphasis is mine):

Let me run over the principal steps. We approached the case, you remember, with an absolutely blank mind, which is always an advantage. We had formed no theories. We were simply there to observe and to draw inferences from our observations. What did we see first? A very placid and respectable lady, who seemed quite innocent of any secret, and a portrait which showed me that she had two younger sisters. It instantly flashed across my mind that the box might have been meant for one of these. I set the idea aside as one which could be disproved or confirmed at our leisure.

My own field of cosmology provides the largest-scale illustration of this process in action. Theorists make postulates about the contents of the Universe and the laws that describe it and try to calculate what measurable consequences their ideas might have. Observers make measurements as best they can, but these are inevitably restricted in number and accuracy by technical considerations. Over the years, theoretical cosmologists deductively explored the possible ways Einstein’s General Theory of Relativity could be applied to the cosmos at large. Eventually a family of theoretical models was constructed, each of which could, in principle, describe a universe with the same basic properties as ours. But determining which, if any, of these models applied to the real thing required more detailed data.  For example, observations of the properties of individual galaxies led to the inferred presence of cosmologically important quantities of  dark matter. Inference also played a key role in establishing the existence of dark energy as a major part of the overall energy budget of the Universe. The result is now that we have now arrived at a standard model of cosmology which accounts pretty well for most relevant data.

Nothing is certain, of course, and this model may well turn out to be flawed in important ways. All the best detective stories have twists in which the favoured theory turns out to be wrong. But although the puzzle isn’t exactly solved, we’ve got good reasons for thinking we’re nearer to at least some of the answers than we were 20 years ago.

I think Sherlock Holmes would have approved.

Top Ten Dubious Science Facts

Posted in The Universe and Stuff with tags , on August 22, 2012 by telescoper

Yesterday evening I joined in a bit of fun on Twitter posting dubious science facts which you can find by looking for the hashtag #dubioussciencefacts if you’re a person who tweets. The idea was to come up with amusing, misleading or just silly statements about science, with as thin a veneer of truth as possible.

The 140-character limit on Twitter makes this kind of game quite challenging, but also quite enjoyable to join in. Anyway, for those of you who don’t tweet, I thought I’d post ten examples of my own creation along with an invitation to contribute your own through the comments box by way of audience participation. Please try to keep your contributions shorter than 140 characters…

Here are my ten:

  1. Galileo is a much more famous scientist than his co-workers Figaro and Magnifico
  2. If the Earth were the size of a golf ball, Jupiter would be as big as Colin Montgomery
  3. It is possible for a spaceship to boldly go faster than light, but only if it uses a split infinitive drive
  4. Organic chemistry is a lot tastier than normal chemistry but also much more expensive
  5. Parity is an important concept in particle physics: PhD students get the same salaries as professors in that field
  6. Galaxies appear to have a flattened shape because they are usually observed using Cinemascopes
  7. Dyson spheres are sources of vacuum energy
  8. The Earth’s rotation means that it will soon have to leave the Solar System in order to throw up
  9. The Coriolis Effect is called the Siloiroc Effect in the Southern Hemisphere
  10. Physics used to be called “natural philosophy”, which means it is philosophy without any bits of fruit in it