April 9, 2003

All your thesis belong to us

Reading Thoughts Arguments and Rants this afternoon while feeling frustrated at a misbehaving web craplet that I am currently authoring, I came across Battlefield God. It is a quiz that tests for consistency in your beliefs about God.

Missing image

I appear to have done pretty well. I took no hits and bit one bullet. The average to date, apparently, is 1.37 hits and 1.10 bullets. From the explanation, I take it to mean that my beliefs are consistent, although in one case I've had to agree to a conclusion most people have trouble with.

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June 9, 2003

Why Israel and Palestine are not morally equivalent

Right now, my opinion of Israel is pretty low, even by my standards. I have been watching the news on the Israeli response to the Bush "Road Map." The good news: Sharon is offering lip service to it. The bad news: nothing but lip service is being offered. But Sharon, for all his faults, is at least understandable. He knows when he's talking shit, and he's been talking shit today. Today's act of tactical assholery: "Speaking to Likud's Central Committee, Sharon said no peace plan with Palestinians was possible unless they ended "terror" first."

Now, remind me, exactly how many troops does the Palestinian army have? Oh yeah, none whatsoever.

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March 4, 2004

Idealisation is the path to the dark side

Brian over at Crooked Timber is thinking about Milton Friedman's defence from the charge that economic modelling is bunk, because empirical evidence shows that people rarely behave they way economic models assume they do.

I think Brian is on the right track by saying that Friedman is partly right to claim that models which generate accurate predictions are useful even when their foundations are known to be crap. However, I think identifying the objects of scientific theories as idealisations is the wrong way to go, and that he's underemphasising something that offers Friedman the possibility of a much stronger defence.

Back in the 19th century, there was some serious economist - I can't remember who, but I remember that he was not considered a crackpot - who thought that the business cycle followed the sunspot cycle. It appeared to fairly accurately predict the British business cycle for a fairly long period. So, he put forward a model that claimed that the sunspot cycle (which was a fairly new discovery at the time) affected agricultural productivity, and that this had a knock-on effect on the whole economy.

This idea was taken seriously, and viewed with some impartiality it isn't ridiculous. In the 19th century, agriculture employed a far larger portion of the population and represented far more of Britain's productivity than it does today. People also spent much more of their income on food and fuel than at the present. So, since they suspected that the sunspot cycle affected weather and climate, they thought it could affect agriculture. There was a plausible theory for how sunspots could cause recessions.

There was only one problem with the theory, and it was a big enough problem to kill that whole line of research. It's complete bollocks.

It turned out that, when they cracked open the books and did an empirical study, they couldn't find any sunspot related variation in agricultural productivity. If Brian's summary of Friedman's arguments are accurate, Friedman is saying that you can't hold the lack of relationship between sunspots and agriculture against an accurate model predicated on just such a relationship existing. It is my understanding that there was enough divergence between the sunspot cycle and the business cycle that any late 18th and early 19th century correlation between the two was almost certainly a coincidence, and that with an additional century and a half of business cycle data, there is no longer any evidence of a relationship between the two.

Brian does point out that a model has more than predictive value, it has explanatory value. Boyle's law - the example usually given of a useful predictive model known to be based on a false assumption - is useful in part because it has explanatory value. Boyle's model assumes that gas molecules in a container collide with the sides of the container, but never with each other. It's a fairly accurate model, because for a lot of kinds of work the difference between the Boyle model and more sophisticated models is quite small, and the calculus involved in Boyle's model is a lot easier.

However, even though Boyle's model includes a known false premise, it still correctly explains why gas pressure changes when volume changes. The basic explanatory value of the model is unaffected by the false premise. Gas pressure is still the force of gas molecules bouncing off the sides of containers, regardless of whether they bounce off each other. Boyle's model is useful not only because it makes fairly accurate predictions, but because it offers a substantial and correct insight into the phenomenon that it's modelling.

The sunspot model of the business cycle, in contrast, doesn't have any explanatory value if its underlying premises are false. Even though sunspots may accurately predict recessions, if sunspot activity has no effect on agriculture, you still know nothing about what causes recessions.

Friedman could have offered a much stronger defence of economic models based on false premises about human behaviour by taking this tack. He might have said, look, the model assumes that humans are rational optimisers and clearly they aren't. But, the real insight of current economic models is that macroeconomic phenomena are an emergent effect of individuals undertaking local, self-centred economic activities. [Okay, in 1953 Friedman would never have used the word "emergent", but there were synonyms he could have used.] Economic models show how individual activity can produce macroeconomic effects, and how macroeconomic policies affect individual behaviour, producing macroeconomic consequences. All this is still true even if humans are half-assed, incompetent utlity optimisers. The kinds of models we produce are just as insightful as Boyle's law, even though - just like Boyle's law - one or more of the premises is nonsense.

I don't think Friedman made that defence. Furthermore, I'm not making any claim about whether or not the kinds of economic models he advanced really are insightful or make accurate predictions.

Brian is right to think poorly of Friedman's claim that facts are irrelevant in the face of theory. (Friedman is starting to sound a bit post-modern to me.) But, I think both Friedman and Brian (and Michael Strevens, who he cites) could make a much better defence of economic models which contain false premises without getting involved in the idea that scientific theories are about idealisations.

Idealisations lead to instrumentalism, instrumentalism leads to behaviourism, and behaviourism leads to the dark side. I'd much rather deal with poorly predictive false theories that tell me something about my real objects of study than highly predictive false theories that tell me about idealised objects.

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April 13, 2004

Alternate Universe SF as a form of Intellectual Masturbation

Once upon a time, when I was a bit younger and a good deal more smart-assed, I used to call alternate universe SF "intellectual masturbation." I felt it was quick, harmless, moderately pleasant and ultimately completely empty and unfulfilling. However, much like the teenage boy who would like to substitute a real, living girlfriend for his right hand and some smut magazines, I regularly pleasured myself with volumes of speculative revisionism in the privacy of my own room, despite a desire for more sophisticated entertainments. Since those days, I have mellowed somewhat. I no longer hold such negative views of alternate history fiction, but I also don't read it very much anymore.

Thus, I was somewhat amused to come across this article from last Wednesday's Guardian by one Tristram Hunt, who "teaches history at Queen Mary College, London." I found it from my hit logs, because of a link posted to me from a rec.arts.sf.written discussion:

Pasting over the past

Far from being a harmless intellectual pursuit, 'what if' history is pushing a dangerous rightwing agenda

Citing as their inspiration the Gwyneth Paltrow character in the film Sliding Doors, a ragged bunch of rightwing historians have clubbed together to issue a new compendium of "what if" essays. Conrad Black, a man facing a few counter-factuals of his own, asks: what if the Japanese had not attacked Pearl Harbor? David Frum, the former Bush speech-writer, wonders: what if Al Gore had won the 2000 presidential election (I thought he did). And John Adamson indulges the dream of Cambridge dons down the centuries: what if Charles I had won the English civil war? [...]

The conservatives who contribute to this literature portray themselves as battling against the dominant but flawed ideologies of Marxist and Whig history. Such analyses of the past, they say, never allow for the role of accident and serendipity. Instead, the past is presented as a series of milestones in an advance towards communism or liberal democracy. It is the calling of these modern iconoclasts to reintroduce the crooked timber of humanity back into history.

The unfortunate truth is that, rather than constituting a rebel grouping, "what if" history is eerily close to the mainstream of modern scholarship. The past 20 years has witnessed a brutal collapse in what was once called social history. The rigorous, data-based study of class, inequality, work patterns and gender relations has fallen away in the face of cultural history and post-modern inquiry. [...]

Instead, what we are offered in the postmodern world of contingency and irony is a series of biographical discourses in which one narrative is as valid as another. One history is as good as another and with it the blurring of factual, counter-factual and fiction. All history is "what if" history.

No doubt, new right legionaries such as Andrew Roberts and Simon Heffer would be appalled to be in the distinguished company of those postmodern bogeymen, Michel Foucault and Jacques Derrida. And they have partly atoned for their sins with a traditional Tory emphasis on the role of great men in history. For "what if" versions of the past posit the powerful individual at the heart of their histories: it is a story of what generals, presidents and revolutionaries did or did not do. The contribution of bureaucracies, ideas or social class is nothing to the personal fickleness of Josef Stalin or the constitution of Franz Ferdinand.

But it is surely the interaction between individual choices and historical context which is what governs the events of the past. As Karl Marx put it: "People make their own history, but they do not make it just as they please; they do not make it under circumstances chosen by themselves, but under circumstances directly encountered, given, and transmitted from the past." [...]

Moreover, as Professor Richard Evans has noted, in this work there is as much a sense of "if only" as "what if". This is history as wishful thinking, providing little insight into the decision-making processes of the past, but pointing up preferable alternatives and lamenting their failure to come to pass. [...]

But "what if" history poses just as insidious a threat to present politics as it does to a fuller understanding of the past. It is no surprise that progressives rarely involve themselves, since implicit in it is the contention that social structures and economic conditions do not matter. Man is, we are told, a creature free of almost all historical constraints, able to make decisions on his own volition. According to Andrew Roberts, we should understand that "in human affairs anything is possible".

What this means is there is both little to learn from the potentialities of history, and there is no need to address injustices because of their marginal influence on events. And without wishing to be over-determinist, it is not hard to predict the political intention of such a reactionary and historically redundant approach to the past.

The citation of the hated "pomos" is pretty cliché. I haven't read a great deal of Foucault and have read virtually nothing of Derrida, but this isn't exactly the message I get from most scholarship that falls under the post-modern label. I think it's just a cheap shot, labelling the looney right with the mark they worked so hard to villify. But, I think the whole critique being offered here is a bit harsh, and I want to examine the underlying claim a little more closely.

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Posted by Scott Martens at 12:53 PM | Comments (13) | TrackBack

August 23, 2004

Towards a Critical Theory of Physics

Via Three Toed Sloth, I see that there is something of a fuss brewing over the anthropic principle's role in cosmology following the distribution of a paper criticising it as inhernetly unscientific.

The argument is made on Popperian grounds, and as Cosma knows I have some fairly serious problems with the Popperian approach. Indeed, Smolin's resumé of the grounds for defining science as identical to falsifiability point to my problems with it.

This point is so basic to how science works that it is perhaps worthwhile taking a moment to review the rationale for it. Few working scientists will disagree that an approach can be considered scientific only to the extent that it requires experts who are initially in disagreement about the status of a theory to resolve their disagreements - to the fullest extent possible - by rational argument from common evidence. As Popper emphasizes, science is the only approach to knowledge whose historical record shows over and over again that consensus was reached among well trained people as a result of rational argument from the evidence. But - and this is Popper's key point - this has only been possible because proposed theories have been required to be falsifiable. The reason is that the situation is asymmetric: confirmation of a prediction of theory does not show that the theory is true, but falsification of a prediction can show it is false.

If a theory is not falsifiable, there is the very real possibility that experts may find themselves in permanent disagreement about it, with no possibility that they may resolve their disagreement rationally by consideration of evidence. The point is that to be part of science, X-theorists have to do more than convince other X-theorists that X-theory is true. They have to convince all the other well trained scientists who up till now have been skeptical. If they don't aspire to do this, by rational arguments from the evidence, then by Popper's definition, they are not doing science. Hence, to prevent the progress of science from grounding to a halt, which is to say to preserve what makes science generally successful, scientists have an ethical imperative to consider only falsifiable theories as possible explanations of natural phenomena.

But this emphasis on coming to a consensus by rational argument is precisely what weighs against a Popperian metatheory of science.

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January 5, 2005

We do what we're told

One doubt
One voice
One war
One truth
One dream

- Peter Gabriel, We do what we're told

Right now, I'm running a piece of code that's scanning the Dutch Wikipedia looking for sequences of words that are all capitalised. I'll let you in on a little non-secret of my trade: this is an excellent way to find important multiword terms useful in categorisation and search. My code is a little clunky, and the Dutch wikipedia contains over a million sentences, so it's taking a while. I'm trying to debug it and optimise it as it runs - one of the wonders of LISP is that you can do that - while I listen to my iPod. Then, Peter Gabriel's We do what we're told comes on.

Simple lyrics for such a depressing song. Anyway, I typed the title into Google to see what would come of it, and I found this book review over at LRB. It seems this last 20th of December was the 20th anniversary of the death of Stanley Milgram, someone I haven't thought about since I was an undergrad. According to LRB, a biography of Milgram has recently been published.

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