Alan Greenspan in 2004

Alan Greenspan, then Chairman of the US Federal Reserve Bank System, speaking in January 2004, discussed the failure of traditional methods in econometrics to provide adequate guidance to monetary policy decision-makers.   His words included:

Given our inevitably incomplete knowledge about key structural aspects of an ever-changing economy and the sometimes asymmetric costs or benefits of particular outcomes, a central bank needs to consider not only the most likely future path for the economy but also the distribution of possible outcomes about that path. The decisionmakers then need to reach a judgment about the probabilities, costs, and benefits of the various possible outcomes under alternative choices for policy.”
The product of a low-probability event and a potentially severe outcome was judged a more serious threat to economic performance than the higher inflation that might ensue in the more probable scenario.”

Limits of Bayesianism

Many proponents of Bayesianism point to Cox’s theorem as the justification for arguing that there is only one coherent method for representing uncertainty. Cox’s theorem states that any representation of uncertainty satisfying certain assumptions is isomorphic to classical probability theory. As I have long argued, this claim depends upon the law of the excluded middle (LEM).
Mark Colyvan, an Australian philosopher of mathematics, published a paper in 2004 which examined the philosophical and logical assumptions of Cox’s theorem (assumptions usually left implicit by its proponents), and argued that these are inappropriate for many (perhaps even most) domains with uncertainty.
M. Colyvan [2004]: The philosophical significance of Cox’s theorem. International Journal of Approximate Reasoning, 37: 71-85.
Colyvan’s work complements Glenn Shafer’s attack on the theorem, which noted that it assumes that belief should be represented by a real-valued function.
G. A. Shafer [2004]: Comments on “Constructing a logic of plausible inference: a guide to Cox’s theorem” by Kevin S. Van Horn. International Journal of Approximate Reasoning, 35: 97-105.
Although these papers are several years old, I mention them here for the record –  and because I still encounter invocations of Cox’s Theorem.
IME, most statisticians, like most economists, have little historical sense. This absence means they will not appreciate a nice irony: the person responsible for axiomatizing classical probability theory – Andrei Kolmogorov – is also one of the people responsible for axiomatizing intuitionistic logic, a version of classical logic which dispenses with the law of the excluded middle. One such axiomatization is called BHK Logic (for Brouwer, Heyting and Kolmogorov) in recognition.

Underground Languages

Conversations overheard on the London Underground in:

Afrikaans, Amharic, Arabic, Cantonese, Catalan, Czech, Danish, Dutch, English*, Farsi, Finnish, French, German, Gujarati, Hausa, Hebrew, Italian, Japanese, Korean, Lingala, Malayalam, Norwegian, Polish, Portuguese, Russian, Spanish, Swahili, Swedish, Tagalog, Thai, Urdu, isiZulu.

* Overheard regional variants of English from:  Australia, Britain (Brummie, Estuary, Geordie, Glasgow-Scottish, Mancunian, Edinburgh-Scottish, RP, Sarf Lonon, Scouse, Ulster, West Country), Canada, Eire, New Zealand, South Africa, USA (Barst’n, Bronx, Brooklyn, ‘Gisland, Midwest, Northeastern, Southern).

Automating prayer

I have recently re-read Michael Frayn’s The Tin Men, a superb satire of AI.  Among the many wonderful passages is this, on the semantic verification problem of agent communications:

“Ah,” said Rowe, “there’s a difference between a man and a machine when it comes to praying.”   “Aye. The machine would do it better. It wouldn’t pray for things it oughtn’t pray for, and its thoughts wouldn’t wander.”
“Y-e-e-s. But the computer saying the words wouldn’t be the same . . .”
“Oh, I don’t know. If the words ‘O Lord, bless the Queen and her Ministers‘ are going to produce any tangible effects on the Government, it can’t matter who or what says them, can it?”
“Y-e-e-s, I see that. But if a man says the words he means them.”
“So does the computer. Or at any rate, it would take a damned complicated computer to say the words without meaning them. I mean, what do we mean by ‘mean’? If we want to know whether a man or a computer means ‘O Lord, bless the Queen and her Ministers,’ we look to see whether it’s grinning insincerely or ironically as it says the words. We try to find out whether it belongs to the Communist Party. We observe whether it simultaneously passes notes about lunch or fornication. If it passes all the tests of this sort, what other tests are there for telling if it means what it says? All the computers in my department, at any rate, would pray with great sincerity and single-mindedness. They’re devout wee things, computers.” (pages 109-110).

Reference:
Michael Frayn [1995/1965]: The Tin Men (London, UK: Penguin, originally published by William Collins, 1965)

The sociology of cosmology

Physicist Per Bak:

“I once raised this issue among a group of cosmologists at a high table dinner at the Churchill College at Cambridge. “Why is that you guys are so conservative in your views, in the face of the almost complete lack of understanding of what is going on in your field?” I asked. The answer was as simple as it was surprising. “If we don’t accept some common picture of the universe, however unsupported by facts, there would be nothing to bind us together as a scientific community. Since it is unlikely that any picture that we use will be falsified in our lifetime, one theory is as good as any other.” The explanation was social, not scientific.” (Bak, page 86)

Reference:
Per Bak [1999]: How Nature Works: The Science of Self-Organized Criticality. (New York, USA: Copernicus)

Self-fulfilling prophecies

It has always struck me that Karl Marx’s prediction that capitalism would be eclipsed by socialism and then by communism was a self-denying prophecy: because he made this prediction, and because of the widespread popularity of his (and other socialists’) ideas, politicians and businessmen were moved to act in ways which allowed capitalism to adapt, rather than to die. It seems that the end of communism may have been partly due to similar reflective-system effects.
In her book, Stasiland: True Stories from Behind the Berlin Wall, Anna Funder writes the following about the opposition to the Socialist Unity Party (SED) in the former German Democratic Republic (the DDR):

I once saw a note on a Stasi file from early 1989 that I would never forget. In it a young lieutenant alerted his superiors to the fact that there were so many informers in church opposition groups at demonstrations that they were making these groups appear stronger than they really were. In one of the most beautiful ironies I have ever seen, he dutifully noted that it appeared that, by having swelled the ranks of the opposition, the Stasi was giving the people heart to keep demonstrating against them. (pp. 197-198)
 

NOTE:  A comment about the processes which led to the end of communism in the USSR is contained in this post.
Reference:
Anna Funder [2003]: Stasiland: True Stories from Behind the Berlin Wall. (London, UK: Granta Books).

When are agent models or systems appropriate?


In July 2005, inspired by a talk on formation flying by unmanned aircraft by Sandor Veres at the Liverpool Agents in Space Symposium, I wrote down some rules of thumb I have been using informally for determining whether an agent-based modeling (ABM) approach is appropriate for a particular application domain.  Appropriateness is assessed by answering the following questions:

1. Are there multiple entities in the domain, or can the domain be represented as if there are?
2. Do the entities have access to potentially different information sources or do they have potentially different beliefs? For example, differences may be due to geographic, temporal, legal, resource or conceptual constraints on the information available to the entities.
3. Do the entities have potentially different goals or objectives? This will typically be the case if the entities are owned or instructed by different people or organizations.
4. Do the entities have potentially different preferences (or utilities) over their goals or objectives ?
5. Are the relationships between the entities likely to change over time?
6. Does a system representing the domain have multiple threads of control?

If the answers are YES to Question 1 and also YES to any other question, then an agent-based approach is appropriate. If the answer to Question 1 is NO, or if the answers are YES to Question 1 but NO to all other questions, then a traditional object-based approach is more appropriate.
Traditional object-oriented systems involve static relationships between non-autonomous entities sharing the same beliefs, preferences and goals, and in a system with a single thread of control.

Pianists

As with violinists I have heard live, I thought it interesting to list the pianists I have heard perform (modulo the vagaries of memory):

  • Caroline Almonte – Mozart’s Concerto for Two Pianos in Eb K365 (MSO, Melbourne 2009)
  • Louis-Victor Bak – (London 2023, recitals at St Mary-Le-Strand and at Steinway Hall)
  • Ksenia Bashmet – Bach’s D Minor Keyboard Concerto (BWV 1052) (Moscow Soloists Chamber Ensemble, London 2011)
  • Alessio Bax (RLPO, Liverpool. Grieg PC with Southbank Sinfonia, London, March 2024)
  • Alasdair Beatson  – Mendelssohn’s Concerto for Violin, Piano and Strings in D Minor (London 2011)
  • Richard Rodney Bennett (Canberra 1976, solo recital of show tunes and jazz standards)
  • Mikhail Bouzine, in a happening at Steinway Hall, London, 13 March 2024, on the theme of love.
  • Giulia Contaldo – Respighi, Wagner/Liszt and Debussy (recital at Famington Farm, 28 January 2024)
  • Imogen Cooper – Bach and Schubert (recital at Famington Farm, 28 January 2024)
  • Emmanuel Despax – Bach/Busoni’s Chaconne and Chopin’s 24 Preludes (solo recital at St John’s Church Waterloo, London, 26 November 2023)
  • Aleksandr Doronin – Ligeti’s Etudes #10 (Der Zauberlehrling) and #13 (L’escalier du diable) (London 2023, Drake Calleja Trust Scholars Concert, 4 November 2023)/ Brahms #1, (Sevenoaks SO, Sevenoaks, 19 May 2024)
  • François Dumont (Brussels 2018)
  • Kathryn Eves – Shostakovich’s Second Piano Concerto (Cheshire Sinfonia, Manchester 2008)
  • Jonathan Ferrucci playing Bach’s Goldberg Variations at King’s Place, London, 11 March 2024.
  • Juan Perez Floristan – in a solo recital at Wigmore Hall, London, 11 April 2024.
  • Nelson Freire – Mozart’s Piano Concerto #20 in D minor and Villa Lobos’ Momoprecoce, Fantasy for Piano and Orchestra (Boston Symphony Orchestra under Marcelo Lehninger at Tanglewood, 2012)
  • Alexander Gadjiev – Chopin’s Concerto No. 2 Opus 21 in F minor (Orchestre Appassionato under Mathieu Herzog, Paris, 13 April 2022)
  • Filippo Gorini – Bach’s The Art of Fugue (Wigmore Hall, London, 23 July 2023)
  • Angela Hewitt – The 48: A truly awesome feat of memory and physical performance, with superb touch and an integrity of interpretation. I don’t think rubato and the North German Baroque belong together but, so not an interpretation to my taste. (Manchester)
  • Rolf Hind (Birmingham, Liverpool, London 2013).  Hind’s masterful performance of John Coolidge Adams’ sublime Phrygian Gates in Liverpool was entrancing and unforgettable, and helped change my mind about minimalism.   I heard him play this again in London in 2013 – again sublime.
  • Stephen Hough (RLPO Liverpool; Manchester)
  • Leslie Howard (Wigmore Hall, London, 16 July 2024)
  • Lucas Jussen and Arthur Jussen – Stravinsky’s The Rite of Spring (Wigmore Hall, London, 2023; Théâtre des Champs-Élysées, Paris, 2023)
  • Elisabeth Klein (1911-2003) – selection of Ligeti’s Etudes (Music Department, University of Liverpool, November 2002). I heard Ms Klein, a student of Bela Bartok, in a recital at the age of 91, playing several of Ligeti’s etudes to an audience of about ten people. She became a public performer of modern piano music only in her sixth decade.
  • Pavel Kolesnikov and Samson Tsoy, 4-hands 1-piano recital, Wigmore Hall, London, 14 March 2024.
  • Pekka Kuusisto (Britten Sinfonia, London, 2012, playing piano part of Stravinsky’s Suites 1 & 2 for Small Orchestra)
  • Ariel Lanyi in a recital at the Wigmore Hall, London, 27 December 2023.
  • John Lill (RLPO, Liverpool)
  • Jan Lisiecki – a solo recital of Preludes, including Chopin’s Op 28 (West Road Concert Hall, Department of Music, University of Cambridge, Cambridge, on 26 February 2024 and again at Wigmore Hall in London, 18 July 2024)
  • Yvonne Loriod – Messiaen’s From the Canyon to the Stars (Australian Chamber Orchestra, Sydney Opera House, 1988).
  • Joanna MacGregor – Bach’s D Minor Concerto BWV 1052 (Manchester)
  • Stephen McIntyre – Mozart’s Concerto for Two Pianos in Eb K365 (MSO, Melbourne 2009)
  • Brad Mehldau (Manchester)
  • Kasparas Mikužis (London 2023, accompanist in Drake Calleja Trust Scholars Concert, 4 November 2023. Sittingbourne, recital, 11 November 2023, recitals in Faversham, London and Famington Farm 2024, Rachmaninov PC2 London 9 February 2024)
  • Arsenii Moon (recital at Steinway Hall, London, 26 June 2024)
  • Olli Mustonen – Shostakovich’s Piano Concerto #1 (BBC SO, with Sergei Nakariakov, London 2013)
  • Sophie Neeb (as part of Klavierduo Neeb, Munich, 13 July 2024)
  • Vincent Neeb (as part of Klavierduo Neeb, Munich, 13 July 2024)
  • Matan Porat in a recital programme of mostly Bach transcriptions at St Martin-in-the-Fields Church, London, Friday February 2024.
  • Roberto Prosseda – UK premiere of Mendelssohn’s 3rd Piano Concerto in E minor (ca. 1840-42, unpublished, completed by Marcello Bufalini) (RLPO, Liverpool)
  • Lauma Skride – Mozart and Mendelssohn Violin Sonatas (London 2011)
  • Gabriele Sutkute – in a solo recital at St-Mary-Le-Strand, London, 23 November 2023.
  • Cedric Tiberghien (RLPO, Liverpool; recitals, London; Ravel’s Piano Concerto in G Major, with Orchestre National de France under Aziz Shokhakimov, Paris 2022)
  • Simon Trpceski (RLPO, Liverpool).
  • Samson Tsoy and Pavel Kolesnikov, 4-hands 1-piano recital, Wigmore Hall, London, 14 March 2024.
  • Tom Zalmanov, Recital on the theme of The Wanderer at Steinway Hall, London, 15 May 2024

Mendelssohn in Wigmore Street

At Wigmore Hall last night was a thrilling performance by the Scottish Ensemble, a string orchestra, together with Scottish pianist Alasdair Beatson. The program comprised works by Stravinsky and by Mendelssohn.  Both the Stravinsky pieces were  rhythmically complex, but hard to parse otherwise – melodic invention, as so often with this composer, was absent and large-scale musical form, if indeed any was present, was not discernible from a single hearing.

I have remarked before that music instantiates or executes a thought process, and some music involves thinking processes that are alien to me.  Most of Stravinsky’s late music is in this category, while that in his middle phase (in the so-called NeoClassical style), while not alien, is quite often banal.  Yet his early music speaks to me profoundly. Last night’s two pieces were clearly challenging to perform well, with the subtle rhythmic interactions and off-piste counting, despite their unpleasant listening.

What I lost there, however, was more than compensated by the Mendelssohn.  The first half saw the Ensemble play two of his Four Pieces for String Quartet, which really should be called “four pieces for String Quartet”, since the composer never grouped them together in this way.  The fugue of the first piece, furiously intense, gives the lie to the claim one still sometimes hears that Mendelssohn’s music lacks profundity or intensity. The playing and cohesion here was superb, and as always with this fugue, spine-chilling. It would be nice to hear this group play some of Mendelssohn’s 12 string symphonies, particularly the fugal movements of the later symphonies.

The real excitement last night came with Mendelssohn’s Concerto for Piano, Violin and Strings, in which Alasdair Beatson played piano and Jonathan Morton, solo violin.   Morton also joined in the ensemble parts when not soloing.  I know this piece very well, although I can recall only once hearing it in performance.  The placement of the performers was somewhat strange, with the high and middle strings behind the piano (and hence behind the upraised lid), dulling their sound.

In any case, the performance was thrilling in the extreme. Beatson captured the many, varied moods of the piano part – from church-like chorale harmonies, through rolling, lieder-style accompaniments for a cantabile violin, to a tempestuousness that made the instrument sound like an angry, rampaging animal.     You can tell how good Mendelssohn was as a pianist himself just by listening to this part, and also how much he enjoyed playing.   The first movement, particularly, has flourishes of pleasure and delight throughout.

Strange, then, was the positioning on stage of the two soloists, with the violinist standing behind the pianist. The first movement has such witty interplay between the two performers – calls-and-responses, mimicry, quoting, and transforming, etc – that for each player not to be able to see the eyes of the other seems untenable.   I cannot imagine young Felix on piano and Eduard Rietz, his friend and violin teacher, for whom this music was written, not facing each other and smiling with each returned flourish.

Like the Australia Chamber Orchestra, most members of the Scottish Ensemble stand while performing.  As with the ACO,  this strikes me as an insidious type of ageism, and is entirely unnecessary.  Only young or very fit people can do this, and one wonders at what average age of ensemble members will the group regain their commonsense. Also, for the historical record, Beatson’s pages were turned by one of the hall staff: even the stage-hands at the Wigmore can read music, apparently.

Program:

Stravinsky:  Concerto in D
Mendelssohn:  Capriccio and Fugue from opus 81 (arranged Morton)
Stravinsky:  Concertino (arranged Morton)
Mendelssohn:  Concerto for Piano, Violin and Strings in D minor.

A review of another concert in the same tour, in Dundee, is here.

This concert is listed in my concatenation of live music events.

More on Solomon Mujuru

Joshua Hammer has an article in the November 2011 issue of the New York Review of Books about the mysterious recent death of General Solomon Mujuru (aka Rex Nhongo) in Zimbabwe. The article  presents an account of Mujuru’s death, an account about which most of us can only speculate.
However, the article has a couple of minor errors, which may not add to a  reader’s confidence in the article’s authority:

  • “When I visited the renovated Victoria Falls Hotel, built by the British colonial government in 1904 at the site of a railway bridge over the Zambezi River . . .”  Except for a brief period of four months in 1979-80, Zimbabwe never had a British colonial government.   Between the first settlement by Europeans in 1890 and the award of self-government (on a restricted franchise) in 1923, the region now called Zimbabwe was governed as a concession by the British South Africa Company (BSAC), advised from 1898 by a partially-elected council.    This might seem a very minor point, but the fact that the modern nation was founded by a brutal, unelected, profit-oriented corporation strikes me as germane to its present sad state under a brutal, unelected, profit-oriented oligarchy.  The violence and brutality of the white occupation is only just beyond living memory, and is certainly within the memories of the children of those affected.     In particular, the fact that white settlers and the BSAC stole farm land from the black inhabitants, and often did so violently, has been used to justify the often-violent and illegal occupation of commercial farms by agents of the Mugabe regime a century later.   While Minerva’s owl is taking flight at dusk, her chickens are busy coming home to roost.
  •  “I headed to a leafy northern suburb and entered the gated estate of Ibbo Mandaza, a liberation war veteran who served for ten years in Mugabe’s cabinet until his ouster in 1990.”  Well, actually, the good Dr Mandaza was never a member of the Cabinet, as far as I am aware, but only a civil servant.   In any case, the word “ousted” implies some sort of estrangement.  In fact,  well after 1990 Dr Mandaza was still working  actively for ZANU-PF victories in national elections.
  • On the other hand, the author could have noted that almost all the residences in the northern (formerly whites-only) suburbs of Harare are gated, so no inference should be drawn from Dr Mandaza’s residence being gated (unlike the situation were his residence to be gated and in the USA).