By BILL GATES
The science writer Matt Ridley made his reputation with books like "The Red Queen: Sex and the Evolution of Human Nature" and "Genome: The Autobiography of a Species in 23 Chapters." His latest book, "The Rational Optimist: How Prosperity Evolves" is much broader, as its title suggests. Its subject is the history of humanity, focusing on why our species has succeeded and how we should think about the future.
Although I strongly disagree with what Mr. Ridley says in these pages about some of the critical issues facing the world today, his wider narrative is based on two ideas that are very important and powerful.
The first is that the key to rising prosperity over the course of human history has been the exchange of goods. This may not seem like a very original point, but Mr. Ridley takes the concept much further than previous writers. He argues that our success as a species, as opposed to earlier hominids, resulted from innate characteristics that allowed us to trade. Not long after Homo sapiens emerged, we were using rare objects, like obsidian blades, far away from the source materials needed to produce them. This suggests that large numbers of commercial links were established even at the hunter-gatherer stage of our development.
Mr. Ridley gives many examples of how exchange allowed groups to thrive, by enabling them, for example, to acquire fish hooks or sewing needles. He also points out that even the most primitive human groups today are open to exchange. I've always thought this openness was surprising, considering the risks involved, but Mr. Ridley convincingly describes its adaptive value.
Exchange has improved the human condition through the movement not only of goods but also of ideas. Unsurprisingly, given his background in genetics, Mr. Ridley compares this intermingling of ideas with the intermingling of genes in reproduction. In both cases, he sees the process as leading, ultimately, to the selection and development of the best offspring.
The second key idea in the book is, of course, "rational optimism." As Mr. Ridley shows, there have been constant predictions of a bleak future throughout human history, but they haven't come true. Our lives have improved dramatically—in terms of lifespan, nutrition, literacy, wealth and other measures—and he believes that the trend will continue. Too often this overwhelming success has been ignored in favor of dire predictions about threats like overpopulation or cancer, and Mr. Ridley deserves credit for confronting this pessimistic outlook.
Having shown that many past fears were ultimately unjustified, Mr. Ridley finally turns his "rational optimism" to two current problems whose seriousness, in his view, is greatly overblown: development in Africa and climate change. Here, in discussing complex matters where his expertise is not very deep, he gets into trouble.
Mr. Ridley spends 14 pages saying that everything will be just fine in Africa without our worrying about negative possibilities. This is unfortunate and misguided. Is his optimism justified because things always just happen to work out? Or do good results depend partly on our caring and taking action to prevent and solve problems? These are important questions, and he doesn't answer them.
In discussing Africa, Mr. Ridley relies on critics who say, essentially, "Aid doesn't work, hasn't worked and won't work." He cites studies, for instance, that show a lack of short-term economic benefit from aid, but he ignores the fact that health improvements, driven by aid, have been a major factor in slowing population growth, which has proven, in turn, to be critical to long-term economic growth. I may be biased toward aid because I spend my money on it and meet with lots of people who are alive because of it, but even if that were not the case, I would not be persuaded by such incomplete analysis.
Development in Africa is difficult to achieve, but I am optimistic that it will accelerate. Science will come up with vaccines for AIDS and malaria, and the "top-down" approach to aid criticized by Mr. Ridley (and by the economist William Easterly) will fund the delivery of these life-saving drugs. What Mr. Ridley fails to see is that worrying about the worst case—being pessimistic, to a degree—can actually help to drive a solution.
Mr. Ridley dismisses concern about climate change as another instance of unfounded pessimism. His discussion in this chapter is provocative, but he fails to prove that we shouldn't invest in reducing greenhouse gases. I asked Ken Caldeira, a scientist who studies global ecology at the Carnegie Institution for Science, to look over this part of the book. He pointed out that Mr. Ridley celebrates declining air-pollution emissions in the U.S. but does not acknowledge that this has come about because of government regulations based on publicly funded science, which Mr. Ridley opposes. As Mr. Caldeira rightly observes, "It is a wonder of development that our economy can grow as air pollution diminishes." What is true of the U.S. case, I'd suggest, can be true of the world as a whole as we deal with the challenges posed by climate change.
"The Rational Optimist" would be a great book if Mr. Ridley had wrapped things up before these hokey policy discussions and his venting against those he considers to be pessimists. I agree with him that some people are overly concerned with potential problems, and I hadn't realized that this pessimism was so common in rich countries over the last several centuries. As John Stuart Mill said in 1828, in a quote from the book that I especially enjoyed: "I have observed that not the man who hopes when others despair, but the man who despairs when others hope, is admired by a large class of persons as a sage."
The most obvious instance of excessive pessimism in Mill's era was the "Communist Manifesto." In one of history's great ironies, Karl Marx used the profits from the German textile mills of Friedrich Engels's father to support the writing and distribution of a political philosophy based on pessimism about capitalism.
Pessimism is often wrong because people assume a world where there is no change or innovation. They simply extrapolate from what is going on today, failing to recognize the new developments and insights that might alter current trends. For too long, for instance, population forecasts have ignored the possibility that population growth would ease as the world became better off, because people who are wealthier and healthier do not feel the need to have so many children. (For more on this issue, see the excellent presentations on the "Gapminder" website of the development expert Hans Rosling.)
A lot of the rhetoric about sustainability implicitly assumes that we will exhaust our natural resources, as though there will never be any substitution of one commodity for another in the future. But there has always been such substitution. The late economist Julian Simon made a famous wager with the biologist Paul Ehrlich, author of "The Population Bomb." In response to Mr. Ehrlich's prediction that population growth would lead to resource scarcity and mass starvation, Simon bet him that the cost of a basket of commodities, including copper, chromium and nickel, would actually decrease between 1980 and 1990. Mr. Simon won the bet because he believed that, despite increased demand, increased supply would win out. And in fact, to take one example, fiber optics soon took the place of copper wire in many communications technologies.
There are other potential problems in the future that Mr. Ridley could have addressed but did not. Some would put super-intelligent computers on that list. My own list would include large-scale bioterrorism or a pandemic. (Mr. Ridley briefly dismisses the pandemic threat, citing last year's false alarm over the H1N1 virus.) But bioterrorism and pandemics are the only threats I can foresee that could kill over a billion people. (Natural catastrophes might seem like good candidates for concern, but I've been persuaded by Vaclav Smil, in "Global Catastrophes and Trends," that the odds are very low of a large meteor strike or a massive volcanic eruption at Yellowstone.)
Even though we can't compute the odds for threats like bioterrorism or a pandemic, it's important to have the right people worrying about them and taking steps to minimize their likelihood and potential impact. On these issues, I am not impressed right now with the work being done by the U.S. and other governments.
The key question that Mr. Ridley fails to address is: What's wrong with worrying about and guarding against threats that might become real, large problems? Parents worry a great deal about their children's safety. Some of that worry leads to constructive steps to keep children safe, and some is just negative emotion that doesn't help anyone. If we all agree to join Mr. Ridley as rational optimists, does that mean that we should stop worrying about trends that might cause problems and not take action to anticipate them?
Mr. Ridley devotes his attention to just two present-day problems, development in Africa and climate change, and seems to conclude, "Don't worry, be happy." My prescription would be, "Worry about fewer things while understanding the lessons of the past, including lessons about the importance of innovation." This might qualify me as a rational optimist, depending on how stringent the criteria are. But there can be no doubt that excessive pessimism may cause problems with how society plans for the future. Mr. Ridley's book should trigger in-depth discussions on this important subject.
Like many other authors who write about innovation, Mr. Ridley suggests that all innovation comes from new companies, with no contribution from established companies. As you might expect, I disagree with this view. He also seems to think that innovation involves simply coming up with a new idea, when in fact the execution of the idea is critical. He quotes the early venture capitalist Georges Doriot as saying that as soon as a company succeeds, it stops innovating. A great counterexample is Intel, which developed over 99% of its breakthroughs after its first success.
Mr. Ridley describes the economy of the future as "post-corporatist and post-capitalist," a silly throwaway phrase. He never explains what will replace all the companies that figure out how to make microchips or fertilizer or engines or drugs. Of course, many companies will come and go—that is a key element of capitalism—but corporations will continue to drive most innovation. It is a dangerous and widespread problem to underestimate the ongoing innovation that takes place within mature corporations.
In his quest to highlight exchange as the key mechanism in the success of our species, Mr. Ridley underplays the role of other institutions, including education, government, patents and science, all of which, especially since the 19th century, have played a central role in the improvements that humanity has experienced. Too often, when Mr. Ridley finds an example that minimizes the contributions of these institutions, he seems to think that he has validated the idea that exchange deserves all of the credit.
I am always amazed by scientific possibilities. Electricity, steel, microprocessors, vaccines and other products are possible only because of our efforts to understand the world and how it works. The scientists and tinkerers who investigate these mechanisms are engaged in a profound process of discovery. Without their curiosity and creativity, no amount of exchange would have produced the world in which we now live.—Bill Gates is co-chairman of the Bill & Melinda Gates Foundation and serves as chairman of Microsoft.