Michael

10 01 2012

Michael. Everyone knew him as Michael.

I was a freshman at Oxford in mathematics, interested in logic. I had been reading Chomsky in my first quarter because I had been told Chomsky had mathematised language. My tutor in algebra, Ian Macdonald (same jacket as in the picture!), an algebraic geometer, suggested I could look at a logic textbook he recommended (which I read with some difficulty over the Christmas break). Derek Goldrei, a graduate student tutoring in logic at my college Magdalen, suggested I listen to Michael’s lectures in set theory.

Michael didn’t lecture. Michael thought out loud. He distributed notes telling his listeners what he was going to be thinking about during that appointment. I learnt, by watching and listening, how to think. About set theory. About inference rules. About non-classical logic (Michael was drawn to intuitionist thinking about mathematics, because he thought it was right to base your assertions on the concrete evidence you had).

I had been attending freshman mathematics lectures, which went “Theorem” “Proof” “Let x be…” and had despaired of ever being the kind of person who thought like that. Then I attended Michael’s thinking-out-loud sessions and understood what really went on in people’s minds; how the symbols were shorthand for notating thoughts. And, in my second year, I could do it! Just like Michael! Actually, not just like Michael. Not anywhere near “just like Michael”. For, as John Mackie is reported to have said in The Times’s obituary, Michael was a genius. Michael was ineffable.

Michael was different. A mass of wavy white hair, he would array himself longitudinally on a bench in the lecture hall and clean his cigarette holder while leaning on an elbow, with his head just above the seat backs, and crack jokes about his friends and colleagues while waiting for the lecture to begin. At which point the jokes would reduce in number as he concentrated on what was being said. If there is anything any undergraduate wished to be in the course of study he had in large part created, Maths and Philosophy, it was to be “just like Michael”.

Simply put, Michael taught me how to think, in logic; by extrapolation, in mathematics. About the deep philosophical questions concerning truth, mathematics, the use of language. Differently put, I learned how to think by watching and listening to him.

When I graduated in 1973, I attended a ceremony in the Sheldonian Theatre, in Latin, much foreshortened from the original, during which my degree was conferred. A ceremony designed over centuries to give its recipients the indelible impression: you have done it! I had done it! I felt it and they’d said it in Latin! After the ceremony, I went straight across the road in my academic dress to purchase a copy of Michael’s new book, on Frege’s philosophy of language. Michael had shown how to think about these matters in pellucid English prose.

I went right afterwards to the other side of the Northern Hemisphere, to Berkeley in California. Michael had helped me get there, for he had written me a recommendation for graduate school. I have no idea what he said, but I it can’t have been all disastrous. (I can imagine: “Ladkin is mortal and does OK for one. But I’m afraid I don’t really know much about mortals.”)

I was required at the end of my first year by Bill Craig, my advisor in Berkeley, he of Craig’s Interpolation Theorem, to take the qualifying exam in philosophy. I protested and threw tantrums and all that, but you know you can’t really rebel. Bill said “you will do it” so I did it. I read Michael’s book, and its seemingly impenetrable prose. And I read it again. And understood more. And again. And more. And again. It wasn’t that Michael’s prose was impenetrable. Michael wrote exactly what he was thinking and his thinking was non-trivial and exact. It took me a while to absorb his train of thought. His prose was, indeed, pellucid. When I had done so, I went into the exam room (actually the philosophy library) for six hours and wrote exactly what I thought about the matters about which I had learned from reading Michael’s book so carefully. Non-trivially and exactly. I think Ernie Adams graded the exam. I passed. Turns out I was the first student in the history of Tarski’s program to pass the philosophy exam in my first year. Thank you, Michael!

(You have to understand – I was rotten at written exams. I got so nervous I couldn’t even read the questions straight. It’s a miracle I ever got into and out of Oxford, at which assessment is based on a student’s brilliance at written exams.)

I saw Michael in Berkeley once. He gave an evening lecture which I attended. I did get to exchange a brief word, amongst all the others earnest to talk with him.

I saw him again in 2009, at the 40th anniversary reunion of Maths and Philosophy graduates in Oxford, of the course which he had done so much to establish, and to which I owe my subsequent career. Derek Goldrei was the First Graduate (he switched in his final year; graduating in 1969 when the course was established). I in 1973. I was one of only two or three from that era at the reunion and felt quite The Establishment. Michael was there, and Dana Scott. Michael was old and frail. Gave an endearing and well-constructed speech. When I approached him after the dinner, he didn’t remember who I was, but then so many had passed through the gate since I had. I simply thanked him. He accepted graciously.

Michael is gone, on 27 December 2011. For me, he was Philosophy. When he was with us, Philosophy was alive. Now he is gone, Philosophy is gone. Maybe not, but it sure feels like it. It turns out I seem to have assumed he was immortal. Apparently not. It is -let me say- hard for me to adjust.

Here is The Guardian’s take. The Times has a fine obituary, forwarded to me by Chris Miller, but it lies behind a paywall, just as now Michael does, though with a currency which I only wish I had. As an atheist without this currency, I can only say: God be with you, as you wished.

Some Coincidences.

Racism. Two of the killers of Stephen Lawrence were convicted in early January 2012. Here is a poem about it by Poet Laureate Carol Ann Duffy. Michael and his wife Ann devoted themselves to race relations in 1960′s and early 1970′s Britain, efforts well documented in the obituaries. He only returned to philosophical work after he felt the efforts to turn Britain away from racist habits had failed. But they haven’t failed, Michael, and neither had you.

Brains. Apparently some people claim now that our brains start to go downhill at age 45 It is not clear this is news: The Guardian had something about it 12 years ago. Michael published his first book at 48, and there followed many more, all of them worth reading very carefully indeed.

Note Added 11.01.2012

It’s not just philosophy. Thinking it over, there are three fundamental developments in technical elementary logic which I have kept coming back to throughout my career. Things which are simple, clear, brilliant, which increase one’s understanding almost instantly, and continually prove to be useful. One is Dana Scott’s Consequence Relations, a formulation of logics which, to me, turns out to be the most efficient way to perform formal deductions, the raw material of logic. I keep meaning to translate into LaTeX the mimeographed notes which Dana handed out almost 40 years ago now. Another is Saul Kripke’s possible-worlds semantics for normal modal logics, and his similar epistemic-worlds semantics for logics of belief and evidence, such as inference in intuitionistic mathematics, and the inferences of Pen Maddy’s “Second Philosopher”. I learnt these partly from Michael. The third is Michael’s and John Lemmon’s formal correspondence between the modal logics from S4 to S5 and the propositional logics between intuitionist and classical.

Second Note Added 11.01.2012

Timothy Williamson, Michael’s successor in the Wykeham chair of Logic (David Wiggins came between Michael and Tim), pointed me to a series of tributes in the New York Times Opinionator blog last week.



The Definition of Risk – Yet Again

16 11 2011

In a message to the York Safety-Critical Systems Mailing List, Tracy White recounted a discussion with someone from the field of “Risk Management” who was taking a course he was giving on system safety. There is apparently a series of international standards, designated ISO 31000, on “Risk Management” (so says Wikipedia ). Tracy says

The term ‘risk’ in 31000 is described as the ‘effect of uncertainty on objectives’ where one of the ‘effects’ can be ‘a deviation from the expected’ (4360 describes it more succinctly as: ‘a chance of something happening’). These ‘risk’ definitions differ markedly from…..

…the standard definition which has been around for 300 years and 10 months: Abraham de Moivre, De Mensura Sortis, or On the Measurement of Chance, Phil. Trans. Roy. Soc No. 329, January, February, March 1711, reprinted with a commentary by O. Hald in International Statistical Review 52(3):229-262, 1984, which may be retrieved from JSTOR. The definition given there is, in modern terms, that risk is the expected value of loss. “Expected value” is a technical term from probability. I give the word-for-word de Moivre definition below.

This definition is also that used for “risk” in finance. See Peter L. Bernstein, Against the Gods: The Remarkable Story of Risk, John Wiley & Sons, 1996/1998. Which book, as the publisher proudly proclaims on the cover, was a “Business Week, New York Times Business, and USA Today Bestseller” and includes praise from reviews by Galbraith, Heilbronner, the NYT, the WSJ and The Economist on its cover. (Indeed, Bernstein is where I got my original lead to Le Moivre).

The meaning of the term in system safety is always close to that of de Moivre, but usually avoids the explicit arithmetic of finance, expected value of loss, by saying “combination of” likelihood and severity. There are good reasons for being somewhat vague, namely that in many cases in system safety the numbers are not there to enable a calculation of expected value. Especially, for example, in a completely new type of system. (An example I am currently working on is the recharging systems for electric road vehicles. There aren’t many around, so in particular there are no reliable numbers on frequencies of untoward things happening.) In response to this common situation, engineers have developed “qualitative” and “semi-quantitative” methods for assessing risk.

One of the issues then becomes what you take the word to mean in technical contexts. Any definition which is not equivalent to the expected value of loss defines a different concept from that, but the same word, “risk”, is used. For good reason: most definitions are conceptually related and the main issue is to get “close” while not having all the numbers.

So what do you do when some branch of human activity, indeed apparently some standard, takes the same word, “risk”, and uses it to mean something different? (I don’t actually know what “effect of uncertainty on objectives” is supposed to mean. I don’t see how “objectives” can be affected by uncertainty. I can see how your chances of attaining them are.)

Well, maybe you cite de Moivre, the finance industry, and system safety use, and say to your correspondant “you mean something different. I think that is unhelpful; and indeed our notion has historical precedence, so for the purposes of this conversation let’s use a different word for your new notion.” Or heshe could say the same to you. In any case, you agree to use two different words.

And for good measure, you write a blog post about it, as here.

This is not a new issue. Here’s a story from six and a half years ago. In the May/June 2005 issue of IEEE Software, Richard Fairley proposed a definition of risk for the Software Engineering Glossary of the IEEE (which is supposed to be canonical, although it turns out that Prof. Fairley doesn’t think so):

(Richard Fairley, proposed IEEE Software Engineering Glossary): The probability of incurring a loss or enduring a negative impact.

So a risk is a to be a probability, which means all risks have values between 0 and 1. Tell that to Lehmann Brothers. Well, I guess you can’t any more. Try Bear Stearns and Morgan Stanley. But we’re talking software, not money.

In common use, someone talking to his teenager speaking of “the risk of your not catching the bus in time” is likely talking about the chances of that event. Someone talking of “the risk that Lehman Brothers will go under” is likely also meaning the chances. But someone talking of “the risk of Lehmann Brothers going under” is likely also thinking of the repercussions as well as just the chances. So much meaning can a relative pronoun versus a copula+gerund carry! As with any other term you wish to be a technical term, you need to decide which meaning (of, here, two) you are going to use. And stick with it. What should be clear is that software engineers working in safety-critical systems need to speak both of likelihoods or chances, and about expected levels of loss. It seems obvious to use “chance” or “likelihood” or “probability” for the former, and some other word for the latter. Since it has been called “risk” for 300 years, why not carry on doing so? And so it is. But some people choose differently. If one is then going to use “risk” to mean “likelihood”, what word does one choose to mean the combination of likelihood and severity? There is not an obvious candidate. But you do need a word for it.

I wrote to the author, Prof. Fairley, Richard Thayer, the person overall responsible for the SW Glossary, and Merlin Dorfman, I believe the IEEE editor responsible for the section, pointing out de Moivre’s definition, the definition from Nancy Leveson’s book Safeware (Addison-Wesley, 1995), and that from the standard for functional safety of E/E/PE systems, IEC 61508, which all cohere modulo the caveats above.

Here is de Moivre:

The Risk of losing any sum is the reverse of Expectation, and the true measure of it is, the product of the Sum adventured multiplied by the Probability of the Loss

Here is Nancy Leveson:

the hazard level combined with (1) the likelihood of the hazard leading to an accident… and (2) hazard exposure or duration…

[The notion of hazard level is] the combination of severity and likelihood of occurrence.

Here is IEC 61508:

combination of the probability of the occurrence of harm and the severity of that harm

I also copied my note to Fairley in this note to the York Safety-Critical Mailing List.

Dorfman agreed that the definition could be misunderstood, but that “I believe the reader is given a fair, complete, and accurate picture of the use of terminology in this area.”. “Accurate”?

What do you do if you are a sofware engineer working in safety-critical systems? Use the IEEE SE Glossary definition, or use the IEC 61508 definition? Use different definitions for different meetings, depending on who is there? And what happens if you misjudge your audience?

Thayer was dismissive. The entire content of his reply:

The overall title of the glossary is Software Engineering Glossary.  This covers it I believe. 

In other words, he doesn’t care much for the dilemma of the software engineer working in safety-critical systems. One could well wonder why he is editing this vocabulary if he doesn’t care about such issues.

I responded to Thayer and Dorfman:

The use in finance and in PRA of the notion of risk equates it to the expected value of loss. A partial list of standards that use some version of this notion is

* IEC 61508, the international standard on functional safety of E/E/PE
safety-related systems
* IEC 300, the international standard on dependability management, in
Part 3, Section 9, “Risk analysis of technological systems”
* IEEE 1228, the standard for software safety plans
* the American Institute of Chemical Engineers guidelines for safe
automation of chemical processes
* US DoD MIL STD 882C, System Safety Program Requirements
* USAF Systems Command, Software Risk Abatement
* CENELEC 50129, Railway applications: Safety related electronic systems
for signalling (the European norm for railways; derivative from IEC
61508)
* European Space Agency Glossary of Terms
* UK Ministry of Defence Standards 00-56, safety
management requirements for defence systems; and Def Stan 00-58,
HAZOP studies on systems containing programmable electronics
* German Standards Institute (DIN), DIN-V-VDE 0801, Principles for
computers in safety-related systems

In particular, I expressed my concern that the IEEE as an organisation had publically given two meanings for risk pertaining to software engineering: one in IEEE 1228 on software safety plans, and another in the Glossary proposed by Prof. Fairley. I got no response.

Prof. Fairley responded, inter alia:

Concerning my definition of risk:  In most, if not all, situations encountered in software engineering, “risk” is the composite result of numerous factors.  In the glossary, I characterize these as “risk factors,” each of which is assigned a probability and an impact (or a range of each).  Risk factors are usually interrelated (e.g., an inaccurate size estimate affects schedule, budget, memory usage; an inaccurate schedule estimate affects product quality) so overall risk (i.e., probability of suffering loss) must be calculated using conditional probabilities or Bayesian analysis.  It is not possible to characterize a situation by a simplistic pair of numbers, unless one is dealing with a narrow, well-defined situation such as a game of chance.  It is dangerous and misleading to attempt to characterize a complex situation in this way.

Given the constraints of a glossary, it was not possible to explain the rationale for my definition or why it differs from the traditional definition; nor was it possible to explain the basis of definition for the other terms in the glossary.

Which to my mind is confused. If risk is “the composite result of a number of factors” each of which is “assigned a probability and an impact”, why ignore the impact and define it as a probability? Either it is a probability simpliciter, or it is the composition of a number of items, each of which exhibits a probability and an “impact”. It can’t be both.

That was it. End of story. The section editor thinks the definition is “accurate”; the Glossary editor is unconcerned; the author is confused. No one seems to worry about the IEEE proposing two incompatible definitions of risk in software contexts.

I wrote to some colleagues I thought might be interested: Dave Parnas, John Knight and Bev Littlewood (as well as a couple of German colleagues), explaining my dissatisfaction with this state of affairs.

Dave sympathised with my frustration, which was similar to his. He said he had seen lots of examples, and that he considered trying to write a glossary for SW terms a fool’s errand, and explained why. John thought this situation to be serious, the Fairley definition of risk wrong, and deserving of public correction. He also said that many people are concerned about a lack of precision and took Dave’s comments to reflect that. Bev strongly agreed with both John and Dave. He was particularly concerned about the dismissive response.

Continuing along the same lines, here is the definition of risk from the US National Research Council study Understanding Risk: Informing Decisions in a Democratic Society (National Academies Press, 1996), p215 (you can read this study on-line):


A concept used to give meaning to things, forces or circumstances that pose danger to people or to what they value. Descriptions of risk are typically stated in terms of the likelihood of harm or loss from a hazard and usually include: an identification of what is “at risk” and may be harmed or lost (e.g., health of human beings or of an ecosystem, personal property, quality of life, ability to carry on an economic activity); the hazard that may occasion this loss; and a judgement about the likelihood that harm will occur.

So descriptions include a likelihood of harm and an identification of what may be harmed or lost. Unless you are a software engineer using the IEEE Glossary (but not IEEE 1228), in which case it’s just a number between 0 and 1.

Here is the definition from a standard text, Probabilistic Risk Assessment and Management for Engineers and Scientists, Hiromitsu Kumamoto and Ernest J. Henley, IEEE Press (them again!) 1996, a book “sponsored by the IEEE Reliability Society”, p2:

Primary Definition of Risk: A weather forecast such as “30% chance of rain tomorrow” gives two outcomes together with their likelihoods: (30%, rain) and (70%, no rain). Risk is defined as a collection of such pairs of likelihoods and outcomes:

{(30%,rain), (70%, no rain)}

So they don’t even go for the combination of likelihood and outcome, nor do they designate certain outcomes as harmful. But if you do designate certain outcomes as harmful, then you can combine these values to calculate de Moivre risk and system-safety risk from this set.

The standard textbook Probabilistic Risk Analysis: Foundations and Methods, Tim Bedford and Roger Cooke, Cambridge University Press, 2001 (not the IEEE for a change :-) ), discusses the definition of risk over some three pages in Section 1.2. They base their notion on that of S. Kaplan and B.J. Garrick, On the Quantitative Definition of Risk, Risk Analysis 1:11-27, 1981.

A risk analysis tries to answer the questions
(i)What can happen?
(ii)How likely is it to happen?
(iii)Given that it occurs, what are the consequences?

Kaplan and Garrick … define risk to be a series of scenarios s_i, each of which has a probability p_i and a consequence x_i.If the scenarios are ordered in terms of increasing severity of the consequences, then a risk curve can be plotted [of severity against probability of at least that level of severity]. The risk curve illustrates what is the probability of at least a certain number of casualities in a given year. Kaplan and Gattrick…. further refine the notion of risk in the following way [to talk about frequency of an event instead of probability, and then uncertainty associated with a frequency]

Again, this concept is somewhat different from that of a number between 0 and 1.

John suggested I contact the then-editor of IEEE Software, Warren Harrison, which I did. Warren suggested that the appropiate action would be a letter to the editor, allowing the author and the section and glossary editors to respond if they wished.

I never did so. I regret it.

So six and a half years later, here I am writing a blog post on it. I doubt the issue will go away. Neither will this note. I do think the IEEE should work to get its definitional house in order.



John McCarthy

11 11 2011

John McCarthy has died. The great John McCarthy. Brilliant and entertaining, fun to be around, accessible unlike many of his stature, who carried an aura about him which blessed you with the feeling, if you came within it, that you were doing the Thinking That Really Mattered. Even if you were just flapping around at a loss for ideas.

The German Wikipedia describes him as a logician and computer scientist. The English version as a computer scientist and cognitive scientist. The German has it right.

John used to be quite happy to get in discussions with everyone about anything and became well known for it as Internet news groups really got started in the mid-1980′s. He had a knack for posing simple questions that turned out to be hard to answer.

And not just in AI. For example, check out his proposal for a new civil right on what counts for him as his personal page:

Remark: Ideally one would put all the information that one considers public about oneself on a page like this. When asked to fill out a form, one would simply put down the URL in place of any information that is on the page and tell the recipient of the form to just look it up.

One step beyond that is that any program needing this public information would just take it from the somewhat standardized web page.

More precisely, here’s a proposed new civil right. No Government agency, educational institution or business should ever be able to require anyone to supply anew information that the institution already has or is publicly available.

Typically for John, it is simple, doable, but somehow not done, and has significant social consequences. Let’s consider it a little further.

There are inadvertent violations. I tried to hand in a technical review of a paper submitted to an IEEE Transactions to the IEEE ScholarOne “system” (I use the word loosely) and found it wouldn’t let me do it without requiring me to fill in a lot of personal information. (I sent the review by email, and someone else has now tweaked the system enough to let me file, apparently.)

But the phenonemon is also used – and this, I suspect, is an insight of John – for political purposes. I had been asked on five or six occasions in the last year by a grant-supported institution with which I am associated to deliver information about activities (publications and talks and so on). Always the same stuff, but somehow not in quite the right format, or not quite the right selection. I began to suspect that someone is looking for a “reason” to ease me out, and so it turned out. Bureaucracy-overload as a political instrument; and of course always deniable.

The focus of this institution is, well, the successor “discipline” (I use the word loosely) to AI. John would have loved it!

Jon Hind informed a mailing list on Tuesday 25th October of the Guardian obituary that had just come out. There is a joint obituary with Dennis Ritchie in The Economist which appeared in the Novermber 5th print edition.

The Economist suggests that John did not suffer fools gladly. That is not quite how it was, as I recall. He engaged with all sorts of people – students mouthing off on Internet bulletin boards, for example, which nobody else did at the time. But he didn’t condescend. Anyone could talk to and argue with John, but he didn’t adjust his intellect to your capabilities – you had to adjust yours to his; for almost everyone an impossibly tall order. As well as being exactly what bright Stanford students need.

The Guardian article seems to me to miss most of what John was about during the 1980′s and 1990′s (the Economist, unusually, even more). Of course, after the invention of LISP, still the longest living programming language with over half a century of use (C, eleven years its junior, still has to catch up), one could regard anything else as a coda. But it was just a start. I’ll talk about the decade I know about, from the mid-1980′s to the mid-1990′s.

John had discovered, or invented, the Frame Problem, with Pat Hayes, and then came up with the cleanest purely technical proposal for solving it, Circumscription. Unfortunately, Circumscription didn’t turn out to solve the Frame Problem sui generis, but it did start a little industry all of its own. This little industry frustrated people such as Danny Bobrow, then-editor in the 1980′s of the premier journal in the field, Artificial Intelligence. Danny is a programmer through and through, who feels that to do AI you have to build stuff, that is, to program. The Circumscription industry consisted of a largish collection of mostly ex-Eastern European logicians, many of them eminent and all of them both capable and productive, who wrote great technical papers in mathematical logic and sent them to the Artifical Intelligence journal- where of course they had to be sent off to be refereed by other members of the group, and they took over about the third of the journal with all that ***** Math!! All good stuff no doubt, but it didn’t seem to some as if much was getting built………

It mirrored a significant split in AI, indeed in all computer science, which continues to this day. There are people who incline to solve problems intellectually before they solve them practically, and there are people who attempt practical solutions and solve, or resolve, issues as they come up to them. In AI in the 1980′s, they were known respectively as “neats” and “scruffies”. The neats have it right in that you cannot program solutions you do not have. The scruffies have it right in that a computational solution to a problem consists in an implementation. You might imagine that they could agree on a division of labor, but research is a little messier than that. The neats have it wrong in that abstraction is also a fine way of subtly changing the problem to fit the solution you happen to have, and the scruffies have it wrong in that a clever programmer can build wonderful programs which fail to solve the problem they set themselves, but “almost” do – the permanent, ineffable “almost”, which turns out to mean “never”.

John’s view on progress was that you knew a field was technically mature when you couldn’t understand the work of someone working on a different problem from you. Let’s turn that on itself. In some sense the division of AI research into neats and scruffies, say Danny’s frustrated view of all that math, could thereby have constituted a proof of some sort of maturity, although the way the squabbles were conducted left many wondering if that was the word for it! Maybe that was John’s point?

And John was the living contradiction to this view on progress. Of course. He could explain to anyone with a modicum of understanding of propositional calculus exactly what he was interested in and what problems he thought were worth solving. Check it out at his group WWW site. They were all so simple! Until you realised that, John being John, if they were really as simple as they looked, he would have solved them already. I recall one evening after dinner at the IJCAI conference in Detroit in 1989 when a bunch of us formal people were chatting away after late dinner. Along comes John. Says, “you know, I was thinking about this…… do you know how to do it?” and posed, as usual, what appeared to be a simple problem in propositional logic. Well, after a few minutes, everyone else made their excuses and left. I couldn’t solve it. Then came another problem. And another. All simple, all propositional logic, all needing to be solved if machines were going to mimic human decision capabilities. And, of course, AI meant that machines should be able to do this, somehow, so even if you programmed them with genetic algorithms or neural-network problem solvers, they would still just have been solving John’s “easy” problems in propositional logic. Surely a problem posed in logic can be solved in logic? Well, sometimes.

This went on for an hour and longer. At such sessions one could choose to feel stupid and frustrated at not being able to solve anything, or to revel in the creativity exhibited before your very eyes. For anyone can solve problems, but very, very few people know how to ask exactly the right questions. John was one. Astonishing performances, puzzles rolling off his tongue as if he were discussing the bus timetable. Anyone – and there were many – who claimed that “symbolic AI” was dead just hadn’t been listening properly. Symbolic AI wasn’t and isn’t “dead”. John’s simple problems need to be solved one way or another. But no longer by him, unfortunately.

Circumscription? Let me have a go. Circumscription is a syntactic (and therefore computationally feasible) way of doing the following. Say you have a description of part of the world in front of you, and what is going on in it. Say your description is in some language which allows deductive inference. Circumscription is a way of drawing rich inferences about features (“predicates”) of that scenario under the supposition that the world doesn’t have anything else in it but those objects expressly described plus whatever else needs to be there for the description to be accurate. Not just rich inferences, more than you could obtain with deduction alone, but rich, correct inferences. To logicians, it is a set of inference rules about what is true in certain minimal models of the set of sentences.

That is logically very important. Modern logic arose with Frege considering the logic of arithmetic, of counting and adding and so on. But in Frege’s logic, it turns out that you can’t just restrict your talk to the positive whole numbers. Circumscription was a way of trying to do just that for “worlds” which had a finite number of objects in them. It resolves many of the issues in the Frame Problem (maybe more appropriately called the Framing Problem), by implicitly defining what you are framing. However, it doesn’t neatly resolve the conundrum posed in 1986 by Steve Hanks and Drew McDermott and known as the Yale Shooting Problem. That was first resolved by using other principles. The conundrum it posed has now dropped out of fashion, as far as I know.

To see the rich the tradition around Circumscription, one may look at the Stanford Encyclopedia of Philosophy entries on Non-Monotonic Logic, on Defeasible Reasoning, on Logic and Artificial Intelligence, on the Frame Problem, on Ceteris Paribus laws (that is, rules based on “all other things being equal”).

John was not concerned merely with mimicking intelligence with machines, but with the more elusive reasoning phenomenon of common sense, which occurred in the title to a collection of his papers in 1990. There was a whole branch of AI research devoted to “common-sense” reasoning about the world; which in turn spawned a branch of reasoning called Qualitative Physics: how the world works ; check out for example this book chapter by Ken Forbus. (John, though, would have distinguished common-sense physics from qualitative physics.) If you put a round ball on a slanting table, it will roll down the slope and drop off the edge and hit the floor just beyond the edge, and how far beyond depends largely on its speed relative to the table when it drops. This phenomenon is known to every two-year-old a couple of decades before they can understand the Newtonian version, but we adults have far more trouble getting a handle on the qualitative reasoning than we do on Mr. Newton’s mathematics. Yet another delicious irony.

And one could go on. Maybe without end. Qualitative physics will not end; it’s a phenomenally hard problem. It may go out of fashion, but it’ll come back. And somebody will have to solve all those common-sense physics problems as well, and maybe differently. Circumscription didn’t solve the Yale Shooting Problem, but it did open up the study of rigorous forms of defeasible reasoning.

And always there was an irony, a delightful little joke in the tail. Somehow, you never quite knew whether you were thinking about a new subject or an elaborate joke. Look closely at the picture in the Guardian. Can you, also, maybe, see the slight smirk that I always thought I saw? Maybe, just maybe, AI was his very biggest joke of all…..



Coda, Interdisciplinary Work, and Scientific Publishing

15 08 2011

It sounds like a mish-mash, doesn’t it? will probably read like a mish-mash, too.

Because true interdisciplinary work always looks that way, I think. That is one of the main points I wish to get across. But first, let me get there.

Concerning my last post, Leslie noted that the condition he labels “FAA requirement” in his slide 4, for 10-10 probability of failure per hour was actually a NASA requirement for the SIFT research. SIFT was the first digital flight control computer, and SRI was supposed formally to verify its operating system. The project didn’t succeed in this original goal, over a decade but, as is often the case, we computer people learned far more, and more fruitfully, from this failure, than we ever would have had it “succeeded”. For example, I am not aware of any formal proof that such-and-such a non-trivial system S is guaranteed free of Byzantine failures, for any system S that is not artificially constructed just for the proof. And that’s thirty years after the papers were published! Conclusions: Lamport and co put their fingers on some things that we just can’t do. Not only that, but they classified a cross-disciplinary problem in a new way. Byzantine failures, as spoken of by Driscoll et al., are a system problem, a mixture of phenomena which have to do with the electronic design, as well as the materials, of which system components are made. Transistors get cracks in them and turn into condensers (a Space Shuttle Byzantine agreement problem). But Lamport et al. turned their efforts to a pure algorithmic problem and published in pure computer-science journals (indeed, the best). Leslie is not a computer scientist who deals with avionics, he is a computer scientist who deals with computer science.

But right on the boundaries also. One of his most insightful (and to my mind, one of the best) pieces of work he ever did was on the collection of issues about arbitration in converting continuous (“analog”) data into discrete (“digital”) data: Buridan’s Principle, whose purely technical contribution rests on a mathematical theorem he proved with Dick Palais, his thesis advisor. You can read Leslie’s account of the odd results of his attempts to publish. He gave it to me sometime in the 1980′s. But since the 1990′s, everyone can know about it and read it at will, because he put it on the WWW. Thank heavens for the WWW!

And that is a point about interdisciplinary work with which I have been struggling now for almost twenty years. One writes a paper on the causal analysis of a computer-related aircraft accident using the Lewis semantics (the Counterfactual Test). One sends it to a computer science journal. Review: “that’s got aeronautics in it, no one in computer science understands aeronautics, better to try an aeronautics journal”. One does. Review: “that’s got logic in it, no one in aeronautics understands logic, better to try a logic journal”. One is not stupid, but if one were, one might try to do so. Anticipated review: “that’s got computer science and aeronautics in it, no one in logic understands computer science and aeronautics, better to try a computer-science-and aeronautics journal.”

And that’s all true and that’s all reasonable. Indeed no one in computer science reads aeronautics journals. No one in aeronautics reads logic journals, and so on. That’s why many engineers working on avionics bus systems still do not know about Byzantine failures, 30 years on.

The result is that most of what I write gets on the WWW and stays there. One can spend one’s time writing, or chasing one’s tail around such publishing conventions, but doing one takes time and effort away from the other, and I prefer writing.

Just to give an indication, one of the pieces of work I performed in the last year of which I am most proud is the analysis of causal explanations of the Concorde accident and assessments of responsibility, which I wrote about in my post Concorde, Ten Years On, Part 2. I see there a series of pressing social and technical issues and their interplay, which people have not satisfactorily come to grips with and I regard that piece as some kind of a start. As I said I’m proud of it. One can’t do that kind of work every day, or at least I can’t. One has to sieze the moment and I did. Actually, that is the way many successful researchers work in math or computer science. Or philosophy, for that matter. You spend most of your time laying some kind of groundwork as best you can, and then you are somehow handed a moment and you sieze it: “I can do that!” and you do. Some more than others.

This wasn’t ever different. Disciplines were partitioned, especially academic disciplines. But one would have thought, as I guessed 15 years ago, that the WWW would make everything different. Mais, plus ça change, plus c’est la même chose.

Some more examples.

I recently organised a Workshop on the Fukushima nuclear accident, inviting largely sociologists and computer-system-safety people. People who read my blog know why I laud the sociologists for their insights into technical matters. When I was thinking we could do this, I asked people about funding. The Scientific Board of CITEC, where I am a PI until November 2012, thought it was a cracking good idea and very relevant and offered financial support. My colleagues at the Centre for Software Reliability in Newcastle upon Tyne, when I called them to apologise that we were withdrawing from their exhibition at the Ada Connection in order to put the money in the Workshop, also offered financial support. Thank you all! And I did approach the German central funding agency for scientific research, the DFG, which had circulated an e-mail saying that in the wake of the tsunami there were instruments available to support cooperative research on the matter in the very short term.

Naive as I am, I took this message literally. I contacted the responsible administrator whose address was on the note. He graciously explained that his “instruments” were limited and didn’t support my workshop idea, and passed my request on to, amongst others, the administrator responsible for the support of engineering research, who replied forthwith in one sentence: “from the point of view of engineering, I don’t see any possibility of support” What? The world has just experienced one of the two most devastating engineering accidents ever, German politicians scrambled over each other to devise our exit from nuclear power, and the prestigious German academic research support agency says it ain’t interested? I put in a carefully worded query asking whether this could really be so, and received no reply.

Now, me being me, I would think they should be ashamed of themselves. But if I said that, I’m sure it would be indicated to me how inappropriate that would be, and really that I don’t understand the formal courtesy structures at play, and so on. Maybe all true. But the fact is that I have an international reputation in accident research, here was a biggie with major political consequences, I invited a bunch of top people to discuss it, they all said yes by return e-mail, and the engineering research support organisation said it wasn’t interested. There is no way around that fact, no matter how pretty the words.

And that illustrates something that I feel is going more and more wrong with academic-type research over the years in which I have been involved with it. I suspect it is particularly acute in Germany. Academic research here after the first degree is performed by scientific employees, by people in temporary jobs. There are no “graduate students” (although that is beginning to change: there are now narrowly-defined graduate colleges which offer competitive scholarships. We have one in Bioinformatics and Genome Research, another in Situated Communication, which I think is now over, and another in Cognitive Interaction Technology, which I think has absorbed it). You want to offer a research topic in an American university, you do so, to all the graduate students, and some one will be attracted to it and come and talk to you. In Germany, you have to apply for funding (mostly from the DFG) for a temporary position to perform the research, then wait for the job applications, and hire someone on the basis of an interview. It’s a lot more work for the faculty member; there isn’t the same personal connection to the bright young people you already know are capable of the work; it’s less flexible (I got three quarters of the way through two other thesis topics before I hit on the one I could finish, and none of them were connected with each other. You can’t do that in a job. Indeed, it took me three jobs!); and I believe the quality of the product suffers (but then, I was at Berkeley. Unfair comparison? Well, no. No German university makes the top fifty in any of the more well-known rankings and I’m talking about possible reasons for that).

Let me amplify a little on that parenthetical comment. I had a colleague here in Bielefeld with over twenty or twenty-five “scientific assistants” in his group, people working at temporary jobs who hoped thereby to get their doctoral degree. At Berkeley, people, even Turing-award winners, had at most four or five doctoral candidates whom they supervised. The key word here is “supervised”. No one person can supervise twenty-five doctoral candidates to anything like the Berkeley norm. Indeed, supervision, such as it was, was mostly delegated to the post-docs. Of which, to achieve the same ratio, one would need five or six or seven (I recall there were three or four). And these doctoral-work supervisors were not Turing-award and like winners, not even NSF Young-Investigator Award winners, such as at Berkeley. They were people who had got their first research qualification and were mostly at the beginning of seeing whether they could make any kind of name for themselves.

A couple of years after I got to Bielefeld, I discovered that somebody in that group had just written a doctoral thesis on temporal reasoning for artifical agents. Temporal reasoning for artificial agents? That’s the very work that I was known for, partly on the basis of which I was hired (here, one is not hired but “called”). This guy had never talked to me. Curious, I looked at the work. After I read the statement of the problem, it was obvious how to solve it. Then I looked at his solution and it wasn’t anywhere near as good. (But there was some program code behind it.) Happens here. Happens quite a lot here. Doesn’t happen at Berkeley, by and large.

I faulted the research structure. The guy had a job, with a job description. He was a nice, friendly and capable guy. At the end of the job was the expectation of a doctoral degree. Which was duly awarded after satisfying the appropriate formal criteria. All very neat and clean. DFG money apparently well spent. But the sum total to the world’s knowledge of how to solve temporal reasoning problems with artificial agents was essentially nil. His energies, and the funding support, would surely have been better spent had he talked to me, and then worked on a problem of the same level of difficulty, but to which the solution was not known.

This is already a lot of anecdotes. But it is hard to see how to get at the point without recounting lots of anecdotes. For each anecdote has its individual answer: it’s a special case; or I misinterpreted; or I was sour at someone; or I’m just being arrogant; or I’m looking for excuses for something I haven’t done or don’t do. Maybe all true, but it is the number of anecdotes, interpreted as the weight of evidence, that persuades reasonable people that there is something to the set-up which encourages all this.

Indeed, I am convinced that the model in which aspiring researchers pick their own topic from amongst those offered, make personal connections with a senior researcher who is able to judge whether they might be capable of completing the work, encouraged indeed required to correspond with more accomplished others who have worked on and solved similar issues, along with the freedom to change topic completely when the current one won’t work out, is a better way to induce productive research than the research-as-job model.

But this heavy structurally-constrained interpretation of what constitutes effective research goes much further. Recall my anecdote about DFG support for my workshop, above. Along those lines, consider the following. I am a Principal Investigation in CITEC (above), whose charter is coming up for renewal and the proposal is about to be submitted. It turns out that the business of saying what my group (essentially of two: me and my post doc) have accomplished and what we will accomplish in the next five-year period was delegated to a young colleague, whose job is supported through the institute through the five-year cycle, as indeed now are all professorial jobs in Germany (tenure has gone) and is thus dependent on the success of the upcoming proposal.

Despite offers to help, my colleague didn’t talk to me at all. Indeed, it took me a certain amount of effort to find out who was writing what about our work in the proposal, since apparently none of the stuff I wrote was going to make it in. He wrote one sentence about the work my group had accomplished over the four years (with apologies that he couldn’t find more). And he found no relevant publications, despite (he indicates) trawling our publications page. Well, during the course of the last few months I have been asked variously for one key publication; for five key publications; for ten publications not necessarily within the CITEC remit, all by various people none of whom are he. The Coordinator of CITEC (effectively the director) asked for a meeting, to explain to me that without any publications it didn’t look good for the proposal to include me.

What? People can’t find stuff I’ve written on the safety of mobile automatic devices in the last five years? Well, of course they can, but you see it doesn’t count. The DFG says peer-reviewed journal articles only.

There we go again. Structural constraints. Nobel-memorial-prize-winning economists, and sociologists, and political scientists, and legal scholars all write blogs. Hundreds and thousands of people read them and comment, including their peers, often in their blogs. Peer-reviewed? Most obviously! I just received a copy of a journal article (counts!) written by two colleagues about two essays (cited) I wrote in this blog. Other colleagues read my posts and they comment!

Another example. We started a mailing list in March 2011 on the Fukushima accident and I recently summarised my contributions, which amounted to 117 A4 pages in 12-pt type, for the workshop proceedings. Now, every word I wrote on that mailing list has been read by eminent colleagues on the list, and they have commented, frankly (it is a closed list). And I have commented on their writing in turn. That’s what you do on such a list, if you’re one of the people who do it (others prefer just to read). Peer review? How much more is it possible to get? And more easily?

The WWW has been pervasive for fifteen years and e-mailing lists for thirty. And there is still no measure of quality of contributions that is acceptable to the German research funding agency? (It is not the only one with such a view.) Astounding! It is not as if this is a hard problem. It would get to be a hard problem if what you want to try to define is The Definitive Measure of Scientific Quality, because there can’t be one. But judging the quality of blog posts or sustained mailing-list contributions is no easier or harder a job than judging the quality of peer-reviewed journal publications, indeed it’s often easier because you can ask more people.

Actually, what happened with the CITEC thing is this. Bernd, Jan and I figured a while ago that our textbook on Safety of Computer-Based Systems, which was been solicited by a major publisher some years ago, would be written and out by now. And we thought one book would likely suffice to show what we’d done. One book is not five published papers; in this case it’s more like fifteen, and there will be more. But it isn’t out. Since it is a text, we need to be sure that the techniques introduced can actually be used by the target audience, students and engineers, and so some of our contributors belong to that target audience (not all textbook writers do this, but I happen to think it’s a very good idea). They are not necessarily as experienced writers as I am, so it simply takes longer than we’d thought. Quite understandable, one would have thought. But apparently there is no reasonable way to say to the DFG that the book is almost finished. (Someone might even want to say that a textbook isn’t research. But this one is, you know, just like Nancy Leveson’s new text. Read that one too!)

Structural constraints, and how they hinder effective support of effective research. Is everyone convinced by now? At least convinced to look at the issue more closely? Shall I stop here then?

Not quite. One more word, back to the original topic. “Interdisciplinary” is one of the buzz words of the new modes of research support. But the problems indicated above of support, publication and assessment of work which crosses traditional discipline boundaries, or the new boundaries left in place by a country’s Scientific Wise Owls and Funding Agencies, are deeper than a buzz word, or even than a buzz concept. The logicians can’t read aeronautics and the aeronauticists can’t read formal logic and the computer scientists don’t understand aerodynamics and the engineers don’t understand the sociologists and I doubt that is going to change rapidly under the hierarchically-directed research-as-job model, buzz word or no.



The Internet as an Educational Tool

1 09 2010

Time was, we thought that people, students, who wanted answers to questions, could come to our office hours, ask, and be answered.

Then we thought that these people could pose these questions to bulletin boards and forums on the Internet, and get answers from all sorts of people, answers which were at least as good as, and maybe even better than, what they could get from us in our office hours.

How wrong we were! For an example of what happens when someone like me attempts to answer a question as if it were posed as a technical question to me during my office hours, see this thread on PPRuNe.

For background, “BOAC” is an experienced, wise, and mostly thoughtful pilot flew Lightnings for the RAF (a wonderful and singular machine, indeed the only aircraft which demonstrated it could outperform Concorde) and most recently Boeing 737 machines. “Pugilistic Animus” is someone who in my estimation has at least a graduate’s grasp of aerodynamics, and likely more – hard for me to tell (but he could, if he chose).

In traditional educational circles such as I have experienced since the 1970′s, the questioner would have posed the question, it would be answered as per my reply, and everyone would have gone back relatively satisfied to whatever they were doing. Handling the question via the forum, and parrying the denigrations so that the questioner, if heshe was still reading, could be more or less satisfied that the original answer was trustworthy, seems to have taken me at least four times as long, and who knows what the questioner makes of the interactions.

So, what conclusion do you, the reader, draw for the future of education via open Internet discussion forums? Please let me know, for I would dearly like it to work somehow, but this example does not give me hope.

PBL



Oxford Up There Again

17 05 2010

The Times has written a blog-article on the proportion of the new UK government who went to Oxford (in fairness, I must point out that some proportion went to the Other Place, which is also rumored to be quite good). A perennial topic. I enjoyed reading the comments. But then I wondered whether the question could be seriously answered, and decided to have a go. (People may see the beginnings of an answer right there.)

My first degree: Oxford; my others: UC Berkeley (also a top tenner). I taught very briefly at Stanford, have worked at unis in Switzerland, France, Scotland and, for 15 years now, in Germany. I think I have a basis for comparison.

I felt like an outsider in Oxford, oppressed by the pressure of trying to achieve, and feeling that I wasn’t up to it, a feeling that it took me another decade to learn to ignore. But 40 years later, most of my matriculating class, including 5 of 7 maths people, turn up every few years for the reunions (one has died, and the Wykehamist disappeared during the course – is that what they learn there? Good prep for a career in offshore finance, I would think :-) ). Two of us turn up for the Maths Institute Garden Party every so often. Contact with pals at UC Berkeley lasted longer, for I was there more than twice as long; but I make only occasional email contact with one or the other.

Last year, there was a reunion to celebrate 40 years of my Oxford degree course, in Maths and Philosophy, and lots of people turned up, including all those still alive – two of them octogenarians – who were responsible for setting it up, as well as all the holders over the decades of the associated Chair. There were more intense discussions over those two days than I have experienced at most conferences. It was my most delightful intellectual experience of the last decade (here, my heartfelt thanks to Hilary Priestley, Dan Isaacson, and Jochen Königsmann for organising it!).

Compare. My Bielefeld colleague, Ipke Wachsmuth, a delightful man whom everybody likes, just celebrated his 60th with a symposium and fun party at which he played lots of blues harmonica (about which I learnt that the hard part is picking the kit that fits the tune). Lots of people there, but just four of us Informatics faculty, out of fourteen. And the oldest of us is 60 (him). It ain’t the same as in Oxford.

So what are the factors? First, some commentators said “contacts”. It is more than that. The college system somehow fosters bonds of shared experience, which may well directly benefit those who go into banking, law, or politics, which are all about trust. (Unlike Maths, which is about being faster than the next guy or gal, and Philosophy, which is about calling other people idiots as politely as possible, a skill only half of which I learnt.)

In the case of those in my small degree program, it is also a matter of shared intellectual value – value fostered by the founders, John Lucas, Sir Michael Dummett, the late Robin Gandy; the first holders of the chair, Dana Scott, Angus Macintyre; and Robin’s successor Alex Wilkie. People at the very top of their field, world-wide, with whom undergrads like me could sit down to tea and discussion a few times a week. That doesn’t happen elsewhere to anywhere near the same extent. But maybe it is invalid to generalise from my degree program to all those at Oxford.

Second, the tutorial system of teaching is unique and structurally supports “thinking outside the box”, if that’s what you can and want to do. The work is much less routine than, say, handing in the weekly homework exercises for a Stanford course, and it is always demanding because tutors tailor it to you – they have to do so, to keep their own interest up. Ah, yes, those tutors who spend more time teaching fewer students than any academics anywhere else in the world. Thank you, people, for your devotion! In my case, especially Ian Macdonald, who encouraged my interest in logic and encouraged me to switch to the “right” degree course, the eccentric Mark Broido, who set the hardest problems but pointed out that the only person who really cared if I solved them was me, an important lesson for a 19-year-old expecting to be told what to do, and Ralph C.S. Walker, who talked me down for two hours after I had royally blown the first paper in Finals, thereby enabling me to do passably on the rest.

Finally, a more diffuse factor. Do I care that the Nobel-Memorial Econ went to UCB last year? A little bit, yes, as with all those other Nobel Prize/Fields Medal/Turing Award winners there. Do I care that 4 out of 24 current UK cabinet members, plus the Attorney General, went to my Oxford college, Magdalen? Yes, most definitely. I am quite proud, even though I know none of them. So, third, the system seems to foster pride in one’s notionally shared common experience. That is a main bonding mechanism in successful governments, isn’t it? And how many experiences in life foster that? Like it or loathe it, it could be a factor. It seems to happen in France, too.

BTW, I am far more Whig than Tory and I guess the cabinet’s now both – does one say Whory, or is that too rude?.
BTW, II, the Other Place is organised more or less the same way, so similar observations hold, but of course just not as well…..
BTW, III, someone pointed out that “the Other Place” should be capitalised. Maybe; I’ve done so. Sorry.

PBL



Reform of the Reform

30 11 2009

Well, folks, the promised “reform of the reform” has started. In my last post, I mentioned some of the troubles the transition from traditional german Diplom to Bachelor’s-Master’s degree courses has caused at my university. The Rectory has made money available for each faculty to discuss the reform of the reform, including overnight accomodation if they want to do it in a “retreat” setting. (I doubt there will be many takers for that. The last thing most German professors wish to do is to hole themselves up in some out-of-the-way place for a couple days with only their faculty colleagues for company.)

Announced last week, my faculty is holding its jaw-jaw next Monday in meeting rooms in some hotel in the center of town (I have thereby discovered a new way to love my dentist, with whom I have an appointment next Monday).

How successful is this going to be? I’ll mention two data points.

First, our degree course in Informatics for the Natural Sciences, and its derivatives, were for many years in the 1990′s and into the 2000′s easily the most successful non-professional course(s) in the university in terms of intake per (tenured) faculty member. And last year our course in Molecular Biotechnology was the most oversubscribed in the university in terms of applications for the limited number of places (by about 20 to 1). So we are doing comparatively pretty well, whatever the complaints.

Second, as far as I know, I am the only member of our faculty with any experience teaching or learning in the Bachelor’s-Master’s model outside of our own university (a good fourteen to fifteen years of teaching in it, in the U.S.). I have degrees from two of the top ten world-ranked universities, and have taught at two of the top ten, in my subjects (as far as such rankings mean anything – see below). I believe I have a feel for what works there, at the best places, and what not. The closest matching experience of anyone else in our faculty is with my two colleagues who were post-docs at ETH-Zürich, which comes in the top-twenty of some people’s lists. But nobody has thought to ask me for my opinion about what is wrong with our study programs and how it may be fixed. Indeed if I were to miss Monday’s discussion altogether I doubt whether anyone would notice.

People who know my writings and contributions to on-line discussion might be surprised that I am locally invisible (except of course when I need to be reprimanded for my poor teaching).

I was one of the two faculty members of my university (which has thousands of faculty) in the mid 1990′s to put most of my teaching materials on the WWW (the other was also a Brit, a computational linguist). Now, more people are doing it, but my material is the most extensive of that of any of my faculty colleagues. So I have been in “e-learning”, as it is called, for fifteen years. I have also been involved in, and made the most extensive content contributions to, two e-learning projects in our faculty led by my colleague who is now the Rector. Despite this, I have been recently invited by our faculty’s e-learning representative to a personal discussion, so that I can find out how e-learning can aid my teaching!

I think this shows at least that we have some communication issues within our faculty. Are we going to be able to solve our course-of-study issues? How likely is it that a group be able to solve a set of pressing organisational problems without soliciting the experience of someone – not necessarily me – who has extensive experience with that form of organisation?

I leave the question as posed.

Ranking lists – a digression

Ranking lists are very variable. For example, The Times/QS ranking has Oxford 5th, Stanford 16th, ETH Zürich 20th, and UC Berkeley 39th. But Berkeley leads the world in the number of Nobel and Nobel-Memorial prize winners, and its Math Department has or had 4 Fields medal winners, out of a total of 48 winners ever, and a couple more who could/should have but didn’t (only Princeton Uni with 6 and IAS Princeton with 5 have more. Cambridge Uni is equal with 4 – but one left for Berkeley :-) ). Compare with University College London and Imperial College, London, at 4th and 5th respectively, which despite their undoubted eminence don’t come close in terms of such winners. Ulinks.com has Stanford at 4th and UC Berkeley at 6th. And UC San Francisco, which is purely a medical school, at 19th! And 4th International Colleges and Universities has the Autonomous National University of Mexico at Number 2, and the Institut Teknologi Bandung in Indonesia at 21st, well ahead of Stanford at 56th. Clearly, any user of these rankings needs to inquire very carefully about the criteria used and whether they are correctly applied.



To Be a Master

26 11 2009

The university where I teach, the University of Bielefeld, is forty years old this month. It was founded as a «reform university». Everything was in one huge building, as may be seen in this picture. The building has two main social features. First, it encourages interdisciplinary work, since students can hop between a lecture in math, coffee, then a lecture in art history, rather than travelling twenty minutes across town to get to specific lectures, as happens in places such as Hamburg (U.S. and U.K universities have this problem long solved, of course, through the campus structure). Second, since every corridor looks the same (apart from the colored stripe down the wall) in this half-kilometer-long construction, it is easy to get lost. Indeed, the majority of visitors to my office are not my students, but those who see the open door (rare in German workplaces) and a person inside, and say “Pardon me, I am trying to find ….”.

There were also supposed to be major reforms in study structure, I am told. Indeed, there is a whole book which explains the concept. I’m from outside and really can’t see the differences. I got here in 1995, with just an inkling of how Humboldt-style German universities work (gleaned largely from a 6-month Zuse Guest Professorship in Hamburg in 1991) and a thought that it was just the thing for me: I can offer my own classes, whatever I want, I have tenure, reasonable pay, fully-qualified pension. Sounds great, right? I thought so too.

The reality is somewhat different. One heads a “group” (mine consisted of me), and one must compete with colleagues, heading other “groups”, for resources. Others had big ones, indeed up to 35 people or so. Guess which way that goes. Hint: I don’t win. If one does not play the game, but prefers, say, to write one’s research papers (primarily what attracted me) and encourage interested students to join in, then one loses out, and can even hit bottom. For example, I sued the university in administrative court in 2005 because I didn’t have enough resources to get my agreed course offering accomplished (the same colleagues, indeed in practical terms the same colleague, who agreed that I should offer a compulsory module in computer networking then failed to provide me with enough resources to offer the required laboratory. I estimated then that it would have cost about €10,000 out of a total faculty budget, for twelve professors at the time, of about €750,000). What about the 25 students who could only take and therefore get credit for part of the module and thereby not finish their course of study? I understand it was offered to them that they could take a database course instead. Keep in mind that these were primarily creative artists who are using new media and really only care about the HW and SW in so far as it enables them to do magical things with computer screens, video cameras, and sound. They have no use for databases. Summary: there is a lot of show about paying attention to the needs of students, and student groups as a whole are “politically powerful”, but incidents like this demonstrate that some of it is pure show and 25 students do not necessarily get what they had been promised. As I said, the reality is somewhat different from the theory.

So where am I going here? Is it just another over-marinated professor grumping on his blog?

No (that is, not just :-) ). This is going to get a bit long, but take heart! There is something here to offend everyone!

The university held an evening reception of talks and laudatios a week ago Tuesday, and planned a “Gala Reception” for this Saturday evening, to celebrate its 40 years. Glossy brochures were printed and distributed; the Great and the Good were invited, as well as people like me (I declined; Saturday night is the one day a week I have the chance really to cook, and I am loathe to forego it for somebody else’s cooking: nobody here uses enough chili). It is all cancelled, at short notice. A group of “students” (some of whom actually were, I am told) tried to invade the main auditorium during the talking-heads celebration a week ago Tuesday. Doors were locked, but they harrassed people who needed to leave early. There was apparently a large police contingent present (as there was in the centre of town for the demonstration earlier in the day), but “the security of the guests could not be guaranteed” and our Rector Gerhard Sagerer called the celebrations off. And then, a couple of days later, the Gala also. This is serious stuff. My partner heard Gerd’s voice cracking up with sadness when he talked on the radio about it, and I would have felt the same way.

There are real issues about study here. And there is a meta-issue, namely, how these issues are discussed, handled, resolved. The protest is at least as much about the meta-issue as about the underlying issues with course reform. But let me deal here with the real issues.

One real issue is that the previous Rector, Dieter Timmerman, presided over a major change in the way study is organised. The university has junked the traditional Humboldtian model and gone for Bachelor’s-Master’s instead. All within about three years (OK, four). The second real issue is that the university has started charging fees per semester of study. There is no doubt that, whether you approve of them or not, these reforms are a significant administrative achievement.

And then, Prof. Dr. Timmermann turned up in our local newspaper on his last day as Rector, indeed as a civil servant, saying there had been a mistake, and “the pressure during study is too high” (English here, original here, as I mentioned in my last post). Which is, as Heiko Holtkamp remarked when the interview appeared, exactly what the student organisation had been telling Prof. Dr. Timmermann, indeed fighting with him about, the years previously. Well, thanks, buddy! You’re gone, leaving the rest of us to deal with it.

Students are significantly involved in government of the university, and are represented as an equal administrative group with professors, teachers, and administrators, at all levels. This is much different from the situation in most U.S. or U.K. universities. The Rectory (that is indeed the translation :-) ) is holding urgent talks with the student representatives about the reforms.

The upside to this student involvement is that students are stakeholders, forming half of the major purpose of the uni (the other half being research; those who do research are, in the German system, not students), and their needs should be appropriately represented. The downside is the usual litany: they are only here for a couple of years, so are oriented to the short term; they have very limited experience, with teaching, with higher education, indeed with anything much relevant over the age of thirty (except for the fine arts); neither do they have any knowledge about how things are achieved – they are here to learn it, after all. And, last but not least, the organisations and their activities are open to manipulation by political operators who are not really students at all and don’t necessarily care about student goals, such as the people who turn up at demonstrations and smash things.

The disruption was commented last week by Klaus Hurrelmann, laudator at the disturbed celebration and a recently-retired “star” of the university, who is a professional youth sociologist and now heads a research institute in Berlin. He praised the new Bachelor’s-Master’s structure, said there is no going back, commented effectively on the social background to the demonstrations (including how they were partly driven by non-student forces), and urged – this is the German solution to everything – talks between students and Rectory.

The student representatives welcomed the increased offer of urgent talks, but criticised Hurrelmann’s view, saying he had been responsible for the introduction of a three-year course which required 28 different examinations. These are called “Leistungsnachweise”, literally, demonstrations of performance, and usually consist of one of: a seminar talk, a term paper, a 1.5-hour written examination, or a 20-minute oral examination; but may be as little as “participation”, which means physical presence, or handing some object in. (Believe it or not, there is a legal requirement for “demonstrating performance” in a course designated as an “exercise”, equivalent to the small groups U.S. Teaching Assistants hold, say for calculus courses. It is that you have to show up once, or to hand something in, even if it is only a piece of paper with your name and some scribbles on it. The joke about passing if you can spell your name is no joke. It’s The Law.)

Compare with the situation in the typical U.S. university. A full-time student is required to take six courses per semester. Each course will typically have homework (weekly or term paper), a fifty-minute midterm examination, and a three-hour final examination. That is, three “demonstrations of performance” per course, one of which, the final exam, is twice the length of any written exam given by us. That is 18 “demonstrations of performance” per student per semester, about four times as much as the 28 over three years about which the student rep complained to our local newspaper.

Whatever one makes of this, I think one can conclude, from the public statements, that many stakeholders – students, faculty and administration – are, in those well-worn words, “not clear on the concept” of what the Anglo-Saxon study model is.

Some comparisons. U.K. universities attracted nearly 350,000 foreign students in 2007, those from the E.U. paying a few thousand pounds fees and those from outside paying more like ten thousand pounds. U.S. universities attracted a little over half a million, with people paying about 50% more (although fees at the most prestigious can be $30,000 per year or more). German fees are in comparison very low – our students pay €700 per year. Germany attracts about 230,000 foreign students. The student representatives are defending the position that study should be free, and that positions in some course of study or other should be available to all.

What is going to happen with all this? I have no idea what is going to happen tomorrow, or next week, but I can make some long-term predictions.

First, I agree with Hurrelmann that there is no going back. The traditional Humboldtian system was elitist, oriented towards the very clever and self-motivated (for many youngsters, that translates to being obsessed by something), but not very good for those youngsters, the vast majority whom I have seen in my 15 years here, who are intellectually somewhat capable, want to learn something more than they had learnt at school, but are not obsessive, and who then wish to get a job preferably using some of those skills. Unlike our former Rector Timmermann, who deprecated it, I applaud the wish of this majority. Indeed, the U.S. and U.K. systems serve it, offering it to half, respectively almost one-third, of their young people. Indeed, they closely fulfil the wish of our student representatives that a position in some course of study should be available to all.

In parallel, one can note that there is a traditional German system of “career education”, whereby if you decide at 19 that you want to be a bicycle mechanic, you can go study and qualify in bicycle mechanics – but woe betide you if you do not have that qualification, but you are good at fixing bicycles, put all your tools in a panel van, and drive around to where the broken bicycles are, rather than requiring customers to bring them to you, for this is a criminal offence (an actual event, from Bielefeld). This system may work for bicycle mechanics (or not, as some will say) but it certainly doesn’t work for those people with an academic high school qualification (“Abitur”) who decide they want to get stuck in to some history, or economics, or informatics, or all three, and then go work for a financial institution, or manage an info-tech company. Our former Rector Timmermann doesn’t think the universities, or the polytechnics (now called “universities of applied science”, in English, on their signs) should be serving this constituency. Follow that line of reasoning, and you will come to the conclusion that no one will be doing it except for business colleges, yet that is the wish of the vast majority of people who graduate from the academic high schools. How’s that for smart thinking from a professional educationalist?

First prediction: Hurrelmann is right, the students are right: the constituency that wants study and then job will be addressed by the universities and polytechnics, because no one else can address it.

Second, the kind of flexibility needed effectively to offer such courses comes at a price. I have solved my lab problem, above, through two grants of €10,000 in two years which comes directly from student fees. The committee that decides this is dominated by student representatives. Now I am negotiating with the university Facilities Management, which has vacillated on either giving me the room I have (which they already equipped with the necessary infrastructure five years ago) or building a new room (they said they would, but after technical assessment it appears it may cost money that no one has). The point: no fees, no lab. No lab, no twenty students per year who have connected computers up to routers and made a net work. Therefore no twenty graduates per year who can go into Bielefeld’s three hundred small high-tech firms and successfully configure their networks against the internet malware that plagues us all. Capisce?

This money, says the students, should come from central government. Let’s look at the plausibility of this. The health care infrastructure is putting unsustainable demands on its backbone personnel, the nurses (I know, my partner is one). There is increasingly less money available for the standard of care to which Germany is used. The state pension system is currently unable to fulfil its projected obligations, as in many other lands. It has been demonstrated in many lands, including Germany I believe, how much more income the average university graduate earns over a lifetime compared with colleagues who graduated similarly from high school but did not pursue a university/polytechnic degree course. The answer is, universally, lots more money. So, as a moral issue, where should our tax money go? Everyone gets sick, and everyone draws a pension except for those who got real sick, and an elite fragment of society goes to university, and pockets thereby over a lifetime more money than otherwise. It’s very hard for people not to get sick, and very hard not to get retired, but very easy to choose not to go to university because of the up-front cost. So where is the general constituency going to lie on that? If you were finance minister, and had to decide where to put your limited pot of money, would you decide to give it to those worried sick about getting sick and not being able to pay (I’ll guess 70% of the voters, and everyone over the age of 55 – this is Germany!), or those wondering how they will pay for the Bratwurst in their old age (I’ll guess over 60% of the voters – this is Germany!), or those studying in universities who complain about fees (about 2 million in 2008/9, 2.5% of the population).

Second Prediction: central government is not going to choose to put all its money into free university education, it is going to prioritise health care and pensions.

Third, consequent, prediction: fees are going to stay, and they are going to get a lot higher to pay for the flexibility which students need, will want and will come to expect. Just as in the U.S. and U.K.

Next, what about all this pressure on students? Let’s look whence it comes. And now I am going to get a bit technical. The courses are generally based on modules consisting of two to four related courses. Each course is worth 2 or 3 credit points, and each credit point is supposed to represent 30 hours of student time, including attending lectures. We package each course of study with three or four compulsory modules, and the rest as a choice from, oh, about 75 offered in our faculty and the same number offered by other faculties. That is a huge amount of choice. It is comparable to the kinds of things one can do in U.S. universities and because it just sort of happened, magically, over the last years, few people appreciate it as much as they could. Now, with so much choice, there is really only one practical way of assessing performance, which is one or more assessments per course. As we have seen, U.S. Universities generally require three per course. We require at most one. So we are at the minimum level already, there is no room for reduction at the level of a course.

The only way to reduce assessments is therefore to bundle modules together, call these super-modules, and to make one or more assessments per super-module. To make a practical difference, one would have to have about three modules per super-module, that is, twelve courses per supermodule (30 credit points) instead of the current two to four (5 or 10 credit points). And, of course, bundling modules together into super-modules comes with a decreased level of flexibility. Proof by example: a student could no longer do my System Safety I: Accident Analysis, learn our method for causally analysing failure behavior, and spend the rest of hisher time doing bioinformatics. Heshe would have to learn SysSafe I and then SysSafe II: hazard and risk analysis (involving all that probability calculation, and we all know how students just love math! :-) ) and do Applied Logic I and II (all that delicious symbol manipulation which some people, incomprehensibly to me, find boring and hard). I get 20 people in SysSafe I, 10-15 in SysSafe II, and so far 3 in Applied Logic – which is a new course and the three are philosophy students who were intrigued by the books the bookstore ordered for me (doesn’t happen with our informatics students, many of whom can’t read books :-) ). If I were to bundle these modules together, I would imagine I would get three or four for the entire super-module, and the philosophy students now learning logic from me would have nowhere to go (my modal-logician colleague in linguistics is overloaded with other things, and we are the only two research-qualified logicians in the university).

Fourth Prediction: Flexibility will be reduced, exactly the opposite of what everyone wants, but the only way to achieve reduced assessment, which will take priority because it is tangible whereas the benefits of flexibility are less so. The compulsory modules in a course of study will be bundled together as far as possible and one assessment will be given per module. The non-compulsory modules will remain as is, with one assessment per course, because you can, tangibly, mix and match courses within a module.

The students don’t realise how risky this is. If you walk in to a half-hour exam, face a grumpy examiner who asks you a bunch of esoteric questions to find out how “clever” you are, and then gives you a poor grade because you concentrated on the wrong thing, you are going to have failed 900 hours of your time (30 credit points, 30 hours per credit point). That is half a year’s full time work (“full-time work” in Germany is about 1800 hours, although it used to be less). That used to happen all the time in the traditional system and is hard to avoid also as an examiner with benign intent, but a student at that time could go away and come back a month later, or six months later, and make good. In the new system, there generally won’t be the time for that.

Fifth prediction: there will continue to be complaints about assessment. This will not be sorted out to everyone’s satisfaction. But students won’t disrupt university events because of it, because it is too esoteric and the political “smashers-up” won’t be motivated.

I conclude with a point that personally means a lot to me. As a faculty, we have worked together hard to put together this new system for our students. We did it intelligently (maybe intelligence is an emergent property :-) ) by tasking an enthusiastic Private Docent with designing the whole new courses of study out of the existing offerings and implicitly promising him we would do whatever he asked (including decide promptly, when he asked for a decision). Miraculously, this worked, and we rewarded him appropriately. We have six new Bachelor’s-Master’s courses of study and to my mind they are all coherent. We have a published module handbook with 150 modules representing over 300 individual courses in it, regularly updated. Did we do it for ourselves? Hell, no. I’d rather be giving a half-dozen half-hour exams a semester and spend my time on my research, as I did before, rather than assessing each of 80-120 pieces of student work per semester, filling in the assessment forms, and fighting with my colleagues as to which form of assessment is appropriate. We did it and do it, we put in this time and effort, because we think, rightly or wrongly, that it is better for the young people who come to us to learn.

It would be nice if this goodwill could be recognised during negotiations. I would be deliriously happy if everyone who came to us for education loved every course and got straight A’s (or 1,0′s as it is here). It has never happened in the history of the world and won’t happen here. We have to do well by the failures as well as by the successes, and this is very much harder. As shown, for those who have not had enough of this by now, in this essay.



Two Birds of Different Feathers

25 11 2009

I was saddened yesterday to learn of the death of John Stallings exactly one year before. John was a mercurial Berkeley mathematician of occasional genius who, if you believed him, mostly enjoyed sleeping, doing nothing, and various scurrilous activities. Including, on the level of barely scurrilous, BSing with graduate students such as myself and my pals about how everything was so pointless you might as well occasionally do a bit of math. Except – and here is the difference – the bits he did occasionally set the world on fire.

The Berkeley Math Department still has his home page up. Please take a look and read especially (if you like math) his note on How not to prove the Poincare conjecture, and his famous reply to a research institute performing a survey on how professors spend their time. For a more sober non-self-assessment, the University obituary hints at just how really good he was.

Today I translated into English an interview given to our local newspaper, the Neue Westfalische (NW for short) by the departing Rector of the University of Bielefeld, Prof. Dr. Dieter Timmermann. The Rector is the academic head of the university. In his office as Rector, Professor Timmermann was a very snappy dresser with a perfect haircut and perfect suit and tie, as befits a man of importance in German society. He presided over a huge transformation of study at the University of Bielefeld, from the traditional german Diplom structure, described briefly in my old note, to a Bachelor’s-Master’s-based structure that is supposed to emulate the “Anglo-Saxon” model of university study. But he seems to think it went wrong. It is not surprising that not everything is perfect – very few German professors (for example, none besides me in my faculty) have any experience of teaching in, say, the U.S., the U.K., or Australia, whence this new model for Germany supposedly came. Imagine if, say, the University of Salford were to move to a traditional German model: take six years to do anything you like, find yourself, take a couple of short oral exams in the middle and a few more at the end, then write a 60pp research thesis in six months or more. Would everything go right? First, one has to know what “right” means! If you change your model so completely, it is no longer so clear. And we might wonder if this is the case now in Bielefeld for many of my colleagues.

I think the views expressed by Prof. Dr. Timmermann will astonish readers in U.K. or U.S. Universities, as they astonished me. Here I just want to point out how surprisingly consonant they are with those of John Stallings (as regards university work, I hasten to add!). More different social creatures in the professorial calling would be hard to imagine!

Where could such a similarity originate? It could originate in general ideas about what a university is for. Germany’s is often said to arise from Alexander von Humboldt’s ideas from 200 years ago, which, in a bowdlerised version that nevertheless reflects a popular conception in German university education, gives lonely original thinkers a place to expound their ideas, surrounded by those willing to learn from them. (This idea is consonant with the medieval idea of a university, except “lonely original thinkers” there were mostly called heretics!) If I had been an algebraic topologist, I could have learned a lot from John, as my pals did. And, people (such as my son’s former teacher) tell me that, if I were a school-level educationalist, I could learn a lot from Prof. Dr. Timmermann.

Another, less complimentary, idea might be termed “the arrogance of the clever”. If you are a mathematician of genius, it doesn’t matter what you do at university, someone will still give you a prestigious job to do what you’re good at, even if you only do it a couple hours a day (but you still have to teach calculus, at least at a U.S. university :-) ). Similarly, if you are a good economist, you can play soccer your first year or two in university and still write your Ph.D. later. My reason for calling it “arrogance” comes from the observation attributed to Thomas Alva Edison that genius is 1% inspiration and 99% perspiration, meaning that even if you’re clever, you don’t get anything except by working hard at it. Indeed, thinking of John’s example one could almost say that genius is 1% inspiration, 60% perspiration and 39% dissimulation, namely hiding the fact you’re breaking a sweat over it at all.

Whatever. In today’s anxious world it is hard to imagine a character like John springing up unformed from under a Little Rock and stubbornly remaining so while pursuing a sometimes spectacularly brilliant career. I feel privileged to have known him and sad that he is gone.