A quiz of marginal interest

November 20, 2013

Two things we know.

(1) Scientific terminology is burdened with the baggage of history, which now makes no logical sense. So… early type galaxies are the ones with late type stars? Errr… And which of these terms relates to a sequence in time? Neither. Right. Very helpful.

(2) When you have to teach something, you finally figure out things that have been bugging you for years.

(3) Nobody expects the … oh. Anyway. Often (1) and (2) combine to make a particularly thick fog.

For some time the term “marginalisation” had been nagging at me, but I ignored it because I had other stuff to get on with. I am referring to the term in statistics. You have a probability density function of two variables, f(x,y), but decide that y is “interesting” and x is “uninteresting”. You then integrate over x to get a PDF p(y) for y alone. This known as “marginalising over x”.

So here is the quiz. My guess is only about seven people will want to take it, but I can’t resist it.

Rule (a) Andrew Liddle is not allowed because I already told him the answer in the pub. Rule (b) No Googling. Rule (c) Never talk about  Stats Club.


Borders Meltdown

October 25, 2013

I do like to keep up to date. So here is a link to a 2009 blog post about the US Republican Party. George Djgovsiki Dvosrgksji Djorgiojski me old mate George from Caltech just posted a link to this on Facebook. It’s based on a book called Albion’s Seed which I have been fond of since ex-SLAC chum Jack Singal bought me a copy as a present. I wrote a connected blog post about Puritan Sex back here.

Short version. Appalachian/backwoods/redneck culture comes from the borders of Scotland and England. This was a war-torn lawless region that bred a culture that had no trust in authority and believed only in family and clan. Fiercely stubborn and violent. The traditional aristocratic slave-owning south on the other hand sprang from a Cavalier culture from Southern England. These two cultures – borderers and cavaliers – have traditionally made up the Republican party, with the aristos keeping the rednecks in check. What has happened over the last decade is that the rednecks have taken over, and are now holding America hostage at the same time as they are a diminishing part of American culture.

Pretty convinced myself, and its a strangely optimistic vision. This is not a crisis of American political culture. Its a crisis of conservatism. It cannot persist. It will implode. It just needs a few old-fashioned Republicans to start rebelling.

I just hope it happens before the Capitalist World System collapses.

Or do I?


The Art of Scientific Knowledge

October 16, 2013

I find myself musing again on the links between Art and Science. No, not the fact that the latest Booker prize winner apparently has an astrological structure, sigh. No, not even The Falling Sky, intriguing blend though it is of academic angst and lesbian lust. No. Umm. Where was I? Oh yes. Art. Grayson Perry has been delivering the first ever cross-dressing Reith Lectures  and very fine they are too. Yesterday’s was about how you judge quality in Art, a famously heated topic. (Can you have a heated topic, rather than a heated debate? Ed.)

There is no objective formula. The choices seem to be (a) The Market. (b) The Club – curators, critics and successful artists. (c) Public Opinion. All the tension seems to come from (c) disagreeing with (b). I have always been fascinated by the way folk are not content to just not like something; they get angry with Art. “My Johnny can do better than that” etc. Oh. Right. How come your Johnny ain’t famous then? I saw this in action the previous summer when visiting a Tracey Emin exhibition at the lovely Turner Gallery in my old home town of Margate. (An art gallery! In Margate!!!) Tracey is not quite my cup of tea but I was giving it a go. Suddenly there were staff scurrying around because a small child had drawn on one of the sculptures. The crowd was instantly split into the horrified bourgeoisie and the cheering polloi. Pardon my mongrel language approach.

So. Thats Art. Science? When we try get all philosophically rigorous we also find it really hard to pin down an objective assurance of truth. Cue pub argument about Hume, Popper, Feyerabend etc. But day by day the situation is the opposite. We know in our guts that the whole point of science is the search for objective knowledge, and that we have found a strange paradoxical but reliable method of getting at it; knowledge comes from honest scepticism.

We also take for granted that the arbiters of good science are us gals and guys in the club. (More gals please.) We don’t think the public should vote on whats true and whats not. There is no market in science. You can’t simply proclaim yourself an expert (though some try). There are not even any gentleman amateur scientists any more. You pass your exams, convince an interview panel, take the Government Shilling or the University Penny, expose your work nervously at conferences full of other club members, and try to decide whether you want to play the Herd Member route or the Lone Wolf route. They can both work, as long as you keep publishing, although the latter is a harder trick to pull off.

But public opinion? You will note its called Public Outreach, not Public Insertion. We generously give them the benefit of our wisdom. Oh, but please, do explain again why you personally believe Einstein was wrong because public opinion is very important to us.  Yeah, right.


Specially for Tim

October 9, 2013

I have been putting on the nosebag tonight. The ESO Committee of Council is here in Edinburgh; the first time we have hosted it for ten years I believe. Anyhoo, I am not on said august body, but as a local astro-big-wig was invited to the nosh. All the chat was about ELT and Brazil of course. Much optimism. Honest. Also a bit of Higgsteria spin-off with Wommers and Jim The Dunlop later in the pub. (The Bow Bar. Some of my readers will know it well.)

Anyhoo, found myself chatting to the Danish rep on the government side. Very cogent woman called Cecilie Tonroe. I think. I was probing her about Danish astronony when Tim De Zeeuw leaned over and said “careful what you say to this man, Cecilie, he has a blog and anything interesting will appear there”.

Anyway. The entire point of this post is to prove Tim right.

Except of course you don’t know what I am not telling you.


Higgsteria : tension builds

October 7, 2013

We’re all a bit tense here in Edinbrrr.  Peter H is understood to be in hiding and quite right too. He’s done more than his duty over many months waving the flag for Physics in general, for UK science, and for Edinburgh University. Adrian Bird didn’t get the Medicine Prize today, so the Edin.Univ. Powers will crossing all possible fingers and toes for tomorrow. Check here. Apparently we expect the announcement to be at 10:45 UK time, but it will initially be in Swedish, so there will be an extra minute or two of hypertension.

Well, we will know soon enough. If you want to entertain yourselves meanwhile, you could try Telescoper’s Poll. Or you could watch Frank Close’s wonderful seminar, which is the clearest explanation I have seen/heard of what its all about, and why a prize specifically for Peter is appropriate. The CERN version seems to be broken, but there is a recording of a version at SISSA that’s audible but bvisually murky. Fascinatingly, Close makes a case for Phil Anderson being an overlooked man, and shows how different parts of Physics can cross-fertilise.

Or if you really want some entertainment, you can see how you can make chocolate from nothing.


Update : Englert and Higgs get it ! But no CERN mega-prize.. Anyway, well done Peter and big cheers in Edinburgh


Women and Strange Powers in Wallachia

September 27, 2013

If you are a British or American astronomer, you have done this many times. You are at a meeting and wander over to a table full of Italians. Or Germans. Or Brazilians, or whatever. They are happily chatting away, but as you sit down they switch seamlessly into English. We Brits radiate a strange field that induces a language phase transition as we approach. Germans do not have this power. Sometimes I am tempted to lean in and out and cause an oscillation. Anyway, we are privileged and rather lucky.

I am currently lecturing at the Opticon Awareness Conference in Bucharest, a kind of Euro-astro-summer-school. This year it is  specifically for students from South-Eastern Europe – Romania, Albania, Greece, Serbia, etc. Very fascinating. Anyway I spent my lunch preventing some Bulgarians and Macedonians speaking their own undoubtedly fine languages. As I walked back I caught up with fellow lecturers Francois Hammer and Alain Le Cavelier, and stopped them speaking French.

Although I have mentioned three male lecturers so far, there is actually a fair sprinkling of female lecturers at this summer school. Maybe not enough, but some. This contrasts rather starkly with the recent STFC summer school, where 0/18 lecturers were female. Well, Peter C already blogged that one. Anyway. I suppose its Rumania One UK Nil.

The female:male ratio varies widely from country to country. UK is better than it was but not so good. Germany is poor. France and Italy have lots of women astronomers. Some of this seems to have been due to strong role models over my lifetime – Suzy Collin, Jacqueline Bergeron, Laura Maraschi, etc. China has lots of female astronomers; Japan extremely few. Is there a pattern here? Whats going on?

There is  also large variation across sub-disciplines in astronomy, which I see in personal experience. When I go to cosmology conferences, women are pretty thin on the ground. When I go to AGN conferences, it’s almost 50:50. Whats that all about? Is it a historical accident? Or something about the way those questions are researched? Herd fashion for aggressive males? Got to be a clue. Some women I know do have a foot in both those camps, so if they happen to be reading, do feel free to comment.


Truth, Belief, and Action

August 27, 2013

My daughter is doing a medical degree. At dinner the other day, I mentioned that a few years back everybody seemed to think that doctors would be replaced by expert systems. Did that happen? Oh no, she said, that’s never going to happen. Its the doctor’s job to decide. Hmm. I see a scientist’s job, much of the time, as a dogged persistence in avoiding deciding, as you hunt down the sometimes stubborn truth. You have to steer carefully between the Scylla of shallow herd fashion and the Charybdis of renegade self delusion, but the aim is constant – to discover what really is the case.

Of course we have statistical methods for dealing with uncertainty, whether it be missing information or true randomness. But even here, as scientists, we avoid jumping to a conclusion, as a fundamentally unsound thing to do. All I can do is tell you that on Hypothesis A, you would have been pretty unlikely to get that measurement. Doesn’t necessarily mean its wrong though… (Pour beer. Cue usual frequentist vs Bayesian argument. Fail to come to conclusion. Drink more beer.)

But for much of our worldly lives, its not about truth, and its not about decision – its about action. You can see this trio as a chain. You cannot take a sensible action unless you have made a wise decision. You cannot take a wise decision unless you know what is and what is not. Each step limits the landscape for the next, but does not fix the path. Well thats what Hume said, which is good enough for me, as he is an Edinburgh Local Hero. Got a statue on the High Street and everything.

We see this every day in public policy – should we punish Assad? Should we allow fracking? Anybody care to postulate the relevant probability distributions in the Syrian case? Thought not. What makes these debates so difficult is not just that we have to act before all the options or their consequences are clear; or that we have to decide whats going on before we know all the facts; its that different people are not even trying to achieve the same ends; and sometimes they don’t even realise this.

A curious and frustrating example is racial profiling. If your aim is to maximise the number of terrorists you stop, regardless of anything else, its hard to deny the statistical fact that if you randomly stop young asian looking men with beards you will do better than if you randomly stop middle aged white women. But if your aim is to minimise the number of terrorists you create over a period of years, you could be making a big mistake.

A few days back, I followed a Twitter link to this beautiful little video. A black American woman explains how she was asked out of the blue for two types of ID, and looked up in a bad-check book, at a supermarket checkout. Her white sister in-law, immediately in front of her, was not asked for ID. The  sister used her white privilege to step in and address the inequity, which is the political point of the story.

However what I found intriguing is that the woman telling this depressingly normal story is so clearly middle class, articulate, intelligent and trustworthy. It sounds like the checkout girl was not being mean, but dim. At the back of her head was not necessarily emotional dislike, but instinctive statistical reasoning – if I stop black people, I will find more bad checks. Well this is probably true, but its a bit like the old gag about the price of fish in Billingsgate market being correlated with the size of women’s feet in China. Most bad checks will be written by members of the impoverished underclass. Due to hundreds of years of social, economic, and political repression, black people in the USA make up a larger then average fraction of the underclass. But the woman in that video is patently not a member of the impoverished stressed out underclass. So what’s depressing is that this isn’t obvious to a supermarket checkout girl. Why can’t she read the signals?

So.. I guess education, in the largest sense, is the answer. Maybe we can’t avoid profiling. We just want better profiling. Academic readers can draw the analogy with citation statistics and divert the conversation as they wish.

Anyway. Got some grant applications to re-read.


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