Probing the vice president's thought processes.

By Paul Krugman
(posted Thursday, Feb. 12)

       A few weeks ago, for some reason that now escapes me, I began to wonder what kind of president Al Gore would make. Never mind his character or his private life--I leave such matters to the experts. What I'm interested in is his mind. After all, Gore--like Clinton--is an unusually bookish politician, one who reads serious tomes on serious subjects and even tries to be a bit of an authority himself. Clinton's pre-presidential intellectual tastes played a big role in determining the shape of his administration's first couple of years. The same might be true of his loyal lieutenant. And so I picked up a copy of Gore's 1992 environmental manifesto, Earth in the Balance: Ecology and the Human Spirit. I can't pass judgment on the scientific merits of the book's environmental analysis, but Gore touches on areas where I do know something and, in so doing, he gives me some important clues to his intellectual style.
       Perhaps the best way to think about Gore the thinker is to contrast him with Clinton. Both men are deeply wonkish, clearly enjoying nothing (well, almost nothing) more than long discussions on how to save the world with a simple 22-point program. But the objects of their affections differ. Clinton is most attracted by matters social and economic, Gore by matters environmental and scientific. Clinton is the kind of guy who attends panel discussions at Renaissance Weekend and pores over the New York Review of Books. Gore pays personal calls on physicists and curls up with Scientific American. And while Clinton, before Bob Rubin took him in hand, was a rather credulous consumer of pop economics, Gore's corresponding vice seems to be pop science.

Which is not to say that Earth in the Balance is entirely free from pop econ. The book contains a chapter, lamentably titled "Eco-nomics," that perpetuates the oddly popular myth that conventional economic theory is constitutionally incapable of dealing with environmental problems. "Many popular textbooks on economic theory fail even to address subjects as basic to our economic choices as pollution or the depletion of natural resources," Gore declares. Actually, I have all the leading introductory texts on my shelf (I'm writing one myself and am trying to steal my competitors' ideas), and every one has an extensive section on environmental issues. One looks in vain in Gore's book for even a mention of the fundamentals of standard environmental economics: pollution as the prime example of an "externality" (a social cost that the market does not properly value), and the standard recommendation that externalities be corrected with pollution taxes or tradable emission permits. (I wrote about the economics of environmentalism in Slate last year, in "Earth in the Balance Sheet.") Since these concepts have actually made their way from theory into practice, one wonders how he missed them. The introduction of tradable permits was an important feature of the 1990 revision of the Clean Air Act, for example, and both fees and permits have been crucial in efforts to protect the ozone layer.
       But for me, at least, the really revealing part of Earth in the Balance was the book's conclusion, where Gore talks about sandpiles and how they changed his life.

Sandpiles, for those unfamiliar with pop science trends, are the motivating example for a concept known as "self-organized criticality," which, in turn, is one of the Big Ideas of so-called "complexity theory." Imagine allowing sand to slowly trickle onto an existing pile. Bit by bit the pile's sides will become steeper. When they become too steep--when they exceed some "critical" slope--there will be an avalanche. In simplified computer models of sandpiles (though not, apparently, in all real sandpiles), a curious pattern emerges. Because the slope of the sandpile is always close to its critical value, dropping a single grain of sand on the pile can produce anything from no effect to a massive sand slide. Specifically, the distribution of avalanche sizes follows a particular mathematical form known as a "power law" that is found in many natural and some social phenomena, such as the sizes of earthquakes and the sizes of cities. (For an example of the power law applied to city size, click here.)
       What Per Bak, the Danish physicist who came up with the sandpile metaphor, has argued is that because sandpile-type models produce power laws, and because there are lots of power laws out there in the real world, such models hold the key to understanding, well, everything. Bak's book explaining this idea is modestly titled How Nature Works. The reaction of his colleagues, as best I can tell, is that the sandpile model is interesting, as is the prevalence of power laws, but that his claims of having developed a universal theory are a bit premature. (For more on power laws, click here.)

If you are wondering what all this has to do with saving the planet, congratulations. But here is what Gore, who made a pilgrimage to see Bak, has to say:

The sandpile theory--self-organized criticality--is irresistible as a metaphor; one can begin by applying it to the developmental stages of a human life. The formation of identity is akin to the formation of the sandpile, with each person being unique and thus affected by events differently. A personality reaches the critical state once the basic contours of its distinctive shape are revealed; then the impact of each new experience reverberates throughout the whole person, both directly, at the time it occurs, and indirectly, by setting the stage for future change. Having reached this mature configuration, a person continues to pile up grains of experience, building on the existing base. But sometimes, at midlife, the grains start to stack up as if the entire pile is still pushing upward, still searching for its mature shape. The unstable configuration that results makes one vulnerable to a cascade of change. In psychological terms, this phenomenon is sometimes called a midlife change.

       This may sound silly, and it is. But it is a time-honored kind of silliness. Gore is in the grand tradition of those who thought that Einstein's theory of relativity refuted not only classical physics but also conventional morality; or those who imagined that because quantum mechanics showed that the apparent solidity of the material world is an illusion, it vindicated the thoughts of Eastern mystics. In the end, these particular confusions don't seem to have done the world any harm. So why not let Gore find solace in sandpiles?

One answer is that the speed with which sexy-sounding scientific ideas get picked up by popular culture is getting alarmingly high: from Physical Review Letters to the latest best seller by Tom Peters almost before you know it. This is arguably starting to distort the practice of science itself. As geologist Nathan Winslow puts it in a gently skeptical review on self-organized criticality, "A theory can, once in the pop science regime, acquire a level of acceptance and momentum that may or may not be warranted by its actual scientific credibility." And the track record of pop science enthusiasms is uniformly dismal. Does anyone remember cybernetics or catastrophe theory? Does anyone know what happened to chaos? It would be unfortunate if the already worrying faddishness of science were to receive a presidential seal of approval.
       I also have a more specific worry: that a President Gore would give undue credence to the views of his favorite pop science heroes and their friends. Occasionally, I have a nightmarish vision in which the Santa Fe Institute, that temple of "complexity theory" (whose heavy hitters include Bak, biologist Stuart Kauffman and, yes, economist Brian Arthur) actually starts having direct input into major policy decisions. Now that would be scary.
       But I guess I shouldn't take that nightmare seriously. For one thing, Earth in the Balance was written a long time ago, and we may suppose that its author has learned a lot since then. And anyway Gore, if and when he becomes president, is no more likely to give his personal gurus any real influence than Bill Clinton would have been to place important policy decisions in the hands of, say, Ira Magaziner.

Missed our links to 1) more information on power laws and 2) an example of how the power law applies to city size? Here they are again.


Earth in the Balance is listed and reviewed at Check out two useful reviews of Per Bak's How Nature Works, one by a physical scientist and another by a social scientist. Aside from sandpiles, the prime advertisement for self-organized criticality has been the Gutenberg-Richter law on earthquake sizes. For a geologist's view, as well as some wise remarks on pop science in general, see the essay by Nathan Winslow. Finally, for a review of the state of "complexity theory," see John Horgan's essay in Scientific American. MSNBC's "Commerce"section offers the latest in business and economics news.

Paul Krugman is a professor of economics at MIT whose books include The Age of Diminished Expectations and Peddling Prosperity. His home page contains links to many of his other articles and essays.

Illustrations by Robert Neubecker.

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