Sunday, February 20, 2005

Science and Global Warming

Global warming has been in the news again in recent days, and once again highlights the disconnect between science and decision making in the Western world. Doubtless this disconnection is not localized to the Western world, but since the West claims a proud tradition of behaving with enlightened objectivity rather than superstitious dogma, we have a particular duty to examine this tradition and see how measures of proof and demonstration are used by our leaders and ourselves to make decisions.

The new evidence for global warming was presented at the annual meeting of the American Association for the Advancement of Science, according to this BBC report. The researchers collected some 7 million oceanic temperature and salinity readings, and concluded not only that temperatures have risen (a debate that is largely over except for people who are sure that the Bible is the only trustworthy source of data for 21st century ocean temperatures), but that among the hypotheses used to account for the changes, two simulations that predicted the warming effects of increased levels of carbon dioxide in the atmosphere hit the nail on the head.

My first compliant about the way this research has been reported is that I have been unable to find a copy of the AAAS paper itself. None of the news reports have contained a link to the article, though they contain copious quotes from the authors and other interested parties. This is typical of the science is presented to the public nowadays. Far from the picture of the Renaissance or enlightenment scholar eager to read about and verify each new scientific breakthrough, science is fed to us with a distance and authority reminiscent of medieval theology. Experts can explain everything about the Universe, but you won't understand and you might as well not try, so here, my dear, is the edited version. An example (which I picked because it is typical of fiarly good scientific journalism, not because it is the worst of the bunch) is this article from the San Francisco Chronicle. (An alternative published a few months ago is this study which was prepared for the Pew Center on Global Climate Change, and certainly does not patronise the reader.)

Other major trends include the increasing reliance of new science upon empiricist rather than rationalist data. Many sceptics would point their finger and say "aha - you can prove anything with computer modelling", but I'm not so worried about this. Philosophically, this is exactly like doing millions of calculations with a pen a paper, and it's a lot easier for an independent reviewer to check someone's algorithm written down in a programming language than it is to check pages and pages of human calculations. Putting the computer in the loop doesn't take the human intellect out, it just speeds things up. It's not the computers that make this sort of research inaccessible. It's the 7 million records of ocean temperature and salinity. That sort of experiment can simply not be reproduced without enormous resources, and of course, even if data was different six months later you could argue that that's because it is - well - just six months later.

This is very very different from the rationalist approach to science that produced such enormous strides through the gravitational and mechanical laws of Isaac Newton, the electromagnetic equations of James Clarke Maxwell, and the special and general theories of relativity of Albert Einstein. Einstein's special theory is a wonderful example - it relies on only two empirical observations or postulates, the first that the velocity of light is constant, and the second that you always get the same results whatever coordinate system you use. Now that's proper science for you ... at least, if one goes in for nostalgia.

Generally I don't. I believe that we're entering a new and exciting epoch of science, and indeed, it is upon us. From climatology to evidence-based medicine to corpus linguistics, empirical methods are shedding new light not only upon their own subject matter, but upon the way our minds work. Descartes' famous "I think, therefore I am" is increasingly understood as only part of the story. Baby humans are apparently not born with the knowledge that if a ball is taken behind a screen and emerges a different colour then there is something funny going on - the register of surprise at this experiment is something that gradually develops. The laws of physics may be true, but they are also learned. Rationalist science may rely on pure intelligence: empiricist science at some level relies also on the tangled web of know-how that is often colloquially called "common sense."

This leads to my main point, deep anger, and deeper fear for the world. Science is changing. Is the interpretation of science keeping pace? Not at all. If anything it is going backwards, and this is bad bad news for us all. Far from responding to scientific results with scientific policies, our leaders are increasingly hiding behind bad science and bad ethics to do whatever they think will please their electors and flatter their images in history. And here's the problem. Whereas rationalist results often rely almost entirely on deduction, empiricist results rely crucially on induction - the acceptance that the future is likely to follow the same trends as the past. But there is always grounds for reasonable doubt with induction - life has its generalisations and its exceptions, and politics has become expert at emphasising one or the other and obscuring the science behind the rhetoric.

Take a simple example - many conservative politicians talk of marijuana as a "gateway drug", citing the fact that (for example) most heroin addicts have previously tried marijuana. And alcohol. And kissing. In deductive logic, the assumption that "A implies B and so B implies A" is known to be a fallacy. In inductive reasoning, people get away with it all the time. This is used, sometimes quite deliberately, to stifle debate into questions like "how come opiates such as morphene are allowed in medicine when they are known to be deadly, and marijuana is completely outlawed." (My reason for citing this example is not to make a case for medical marijuana in this instance, but to point out how unscientific are the decisions made on our behalf and the rhetoric used to uphold them.)

The deadliest example is the contrast between the politics of profit and the poilitics of fear. If a man carrying a gun and wearing a turban poisons your water once, it's a dastardly act of terrorism, but don't worry, our leaders are on to him already and are going to attack his country before he attacks ours. If, on the other hand, a man wearing a suit and tie explains to a man wearing a wig and gown that a man wearing a blue overall was just doing his job, and the EPA had issued a license, was monitoring all the activities, and they were all within "safe" levels, then everything is perfectly legal. Kicking up a fuss in this instance is deeply frowned upon - frivolous lawsuits cost jobs, so don't rock the boat.

An astonishingly bad example was the attitude of the UK government to the growing threat of BSE or "Mad Cow Disease" in the early and mid 1990's. In many reports and parliamentary sessions, the mantra was quoted again and again that there was no proven link between feeding dead sick sheep to cows and any human suffering. A typical political example of demanding
a deductive proof, because there was money riding on the issue in the short term. Of course, there was orders of magnitude more money riding on the issue in the medium to long term, but that would demand that our leaders were prepared to reason empirically, arguing that if something sounds stupid and negligent, it probably is. Feeding sick sheep to vegetarian cows and then eating the cows was always a gross violation of common sense, and a large proportion of the British public ("those emotional unscientific bleeding-heart liberals at it again ...") were outspokenly aware of this.

Most recently, the contrast between fear-politics and profit-politics is heartbreakingly obvious, but it needs to be said again and again. Out-of-date reports, a photograph of an Iraqi with a briefcase in Nigeria, and the fact that Iraqi officials and Islamists had potentially been within 20 miles of Prague at the same time, was enough for any reasonable person to be beyond doubt - Saddam Hussain had weapons of mass destruction and was ready to push the button any minute now. And Blair and Bush could simply not afford to risk their people's safety any longer.

Faced, on the other hand, with 7 million observations of ocean temperature and salinity, we have the following call to arms.
"Our position has been the same for a long time," said Bill Holbrook, spokesman for the White House Council on Environmental Quality. "The science of global climate change is uncertain."

I suspect that this phrase may become famous. It's true, of course. Empirical science is uncertain. To know that a virus causes sickness, you do not predict with certainty which members of the population will fall sick and which will stay healthy. You see enough sickness and you take action.

According to the cartoon we were taught in school, the middle-ages ended when Science broke free from the Church and spoke with its own voice. The challenge today is far greater, because the earth is at stake. Science must break free of the web of ego, profit ignorance and speak with its own voice, so clearly that people are compelled to believe and change their ways. Science will triumph, or we are doomed to great suffering and possibly extinction. And no, I cannot prove this.

2 comments:

Mike Higgins said...

Another instance of the failure of leaders and the public to interpret science is the ongoing Creationism, *cough* Intelligent Design, debate in our schools. (At least here in the great Commonwealth of Pennsylvania and our neighbor to the west, Ohio.)

The method of the Intelligent Design attack on science is a fascinating thing.

Step one is to announce that evolutionary biology is "only" a theory. This, of course, is true, but it relies crucially on the fact that the public at large doesn't distinguish between a scientific theory (a falsifiable hypothesis that is supported by much objective evidence and makes predictions) and an opinion (a much weaker thing).

But, on the face of it, it's hard to criticize step one because, of course, evolution by natural selection is just a theory, and in some ways equivalent to the theory of phlogiston chemistry. Except not falsified ;-)

Intelligent Design goes on to step two, which is to make a claim: some features of the natural (biological) world are "too complex" to be "explained by" natural selection and therefore must be explained by an intelligent designer.

There are lots of problems with this. Perhaps the most annoying is that the set of unexplainable features is left open. So anytime a feature is successfully explained, you just pick another. This has happened countless times in the history of ID, but no one abandons the claim in favor of one that works better; they just re-trench. I suppose eventually they will run out of biological features, but it could take decades.

One that bugs me personally a lot is that the notion of "too complex" is not even remotely rigorous. Complexity is definable in a variety of mathematical contexts, including algorithmic complexity and algorithmic information theory, but it's not obvious how to make those concepts apply and no one has seemed to even try.

Finally, ID doesn't seem to make predictions that could be used to validate it or falsify it. In particular, an obvious prediction of ID would be that, if there's an intelligent designer, you would expect that biological systems be, well, intelligently designed. In fact, if you examine biology, you note a lot of areas in which it looks like the designer was a bit nuts. A serious treatment of this appeared recently in the New York Times, and a more facetious one has been floating around the net for years.

This lack of evidence for the intelligence of the purported designer makes the inductive step from "too complex" to "must have been designed" kind of weird, but the ID guys would never be content with simply fixing a problem in evolutionary biology (if they actually found one). They have their pre-conceived crypto-god to work into things. And they aren't going to let the conclusion they want go no matter how untenable it is on the evidence.

So, because ID fails to make falsifiable claims, it is content-free as a scientific theory. But it's still a perfectly good opinion, and we come back to the crucial reliance on public mis-understanding of what a theory is. So the ID guys demand that we treat their crackpottery with the same credence as one of the most well-supported scientific theories ever devised.

I can only hope that this whole thing causes 6th grade science teachers to spend more than a day on the scientific method in the future. Maybe that will help with the global warming "debate" as well. (Or perhaps it will just be too little too late, and some future alien will write a book about unaccountably dumb the humans were.)

Dominic said...

Scary stuff. In many ways I have a sense of sympathy with the ID position - at least, it has echoes of Aristotle's prime mover, "nature does nothing without a purpose", etc.

But, as Mike's jovial link demonstrates, Aristotle was a bit wrong on this issue. Nature does a whole load of things without purpose - or at least, things whose purpose goes out of context pretty quickly. "Pretty quickly" for these puposes is propably tens of thousands of years. Don't worry, Creationists, nobody is trying to encroach upon your 5000-years-is-antiquity timeframe.

The huge discrepancy Mike alludes to is between theories that predict and theories that don't. Now, "predict" could mean many things (lit. "before statement"), and the problem is that Intelligent Design, as a theory, does none of these things.

Yes, there are gaps in the fossil record (for most scientists, this advocates getting a research grant and a shovel, not a new theory). Yes, if you just take entropy as a baseline, there's a hell of a lot of explaining about the universe that needs doing. But "lack of evidence for A" is not scientific evidence for B, any more than "I'm not wearing blue socks" is evidence that I'm wearing red socks. OK, it makes it marginally more likely, especially if you've done a thorough empirical survey of sock usage. I don't think the ID people have done anything of the sort.

I must stress that evolution does not contradict the idea of intelligent design - they have a common root, which is Aristotle's "nature does nothing without a purpose". Darwin even includes a reference to Aristotle's biology as a footnote to the first page of the Origin of Species, to make it clear how much he inherited from this framework (including the notion of inheritance). As described above, though, it seems like nature does a fair bit that doesn't quite cut the mustard. This is anathema to Aristotle's theory, but kind of works in Darwin's, because you can have pleny of shoots on the Tree of Life that never really sprouted. This of course is the main difference between two of histories greatest biologists - Darwin realised that mutability could account for the apparent weirdness of the species around him.

What makes intelligent design unscientific is not the conclusion, it's the reasoning from lack of evidence.
"X doesn't explain it so it must be Y". Lightening can't be natural so it must be the wrath of the Gods.

There are at least 5 traditional arguments for the existence of the divine in creation: ontological, causal (Aristotle's prime mover), teleological (Paley's watch), moral (Kantian) and experiential (possibly the least scientific because the most specific). None of these fall back to the primitive "well, I couldn't explain it any other way", except for the teleological, of which ID is really a primitive version.