Ten years ago, science journalist John Horgan published a provocative book suggesting that scientists had solved most of the universe's major mysteries. The outcry was loud and immediate. Given the tremendous advances since then, Discover invited Horgan to revisit his argument and seek out the greatest advances yet to come.
One of my most memorable moments as a journalist occurred in December 1996, when I attended the Nobel Prize festivities in Stockholm. During a 1,300-person white-tie banquet presided over by Sweden's king and queen, David Lee of Cornell University, who shared that year's physics prize, decried the "doomsayers" claiming that science is ending. Reports of science's death "are greatly exaggerated," he said.
Lee was alluding to my book, The End of Science, released earlier that year. In it, I made the case that science—especially pure science, the grand quest to understand the universe and our place in it—might be reaching a cul-de-sac, yielding "no more great revelations or revolutions, but only incremental, diminishing returns." More than a dozen Nobel laureates denounced this proposition, mostly in the media but some to my face, as did the White House science advisor, the British science minister, the head of the Human Genome Project, and the editors in chief of the journals Science and Nature.
Over the past decade scientists have announced countless discoveries that seem to undercut my thesis: cloned mammals (starting with Dolly the sheep), a detailed map of the human genome, a computer that can beat the world champion in chess, brain chips that let paralyzed people control computers purely by thought, glimpses of planets around other stars, and detailed measurements of the afterglow of the Big Bang. Yet within these successes there are nagging hints that most of what lies ahead involves filling in the blanks of today's big scientific concepts, not uncovering totally new ones.
Even Lee acknowledges the challenge. "Fundamental discoveries are becoming more and more expensive and more difficult to achieve," he says. His own Nobel helps make the point. The Russian physicist Pyotr Kapitsa discovered the strange phenomenon known as superfluidity in liquid helium in 1938. Lee and two colleagues merely extended that work, showing that superfluidity also occurs in a helium isotope known as helium 3. In 2003, yet another Nobel Prize was awarded for investigations of superfluidity. Talk about anticlimactic!
Optimists insist that revolutionary discoveries surely lie just around the corner. Perhaps the big advance will spring from physicists' quest for a theory of everything; from studies of "emergent" phenomena with many moving parts, such as ecologies and economies; from advances in computers and mathematics; from nanotechnology, biotechnology, and other applied sciences; or from investigations of how brains make minds. "I can see problems ahead of all sizes, and clearly many of them are soluble," says physicist and Nobel laureate Philip Anderson (who, in 1999, coined the term Horganism to describe "the belief that the end of science . . . is at hand"). On the flip side, some skeptics contend that science can never end because all knowledge is provisional and subject to change.
For the 10th anniversary of The End of Science I wanted to address these new objections. What I find is that the limits of scientific inquiry are more visible than ever. My goal, now as then, is not to demean valuable ongoing research but to challenge excessive faith in scientific progress. Scientists pursuing truth need a certain degree of faith in the ultimate knowability of the world; without it, they would not have come so far so fast. But those who deny any evidence that challenges their faith violate the scientific spirit. They also play into the hands of those who claim that "science itself is merely another kind of religion," as physicist Lawrence Krauss of Case Western Reserve University warns.
Argument: Predictions that science is ending are old hat, and they have always proved wrong. The most common response to The End of Science is the "that's what they thought then" claim. It goes like this: At the end of the 19th century, physicists thought they knew everything just before relativity and quantum mechanics blew physics wide open. Another popular anecdote involves a 19th-century U.S. patent official who quit his job because he thought "everything that can be invented has been invented." In fact, the patent-official story is purely apocryphal, and the description of 19th-century physicists as smug know-it-alls is greatly exaggerated. Moreover, even if scientists had foolishly predicted science's demise in the past, that does not mean all such predictions are equally foolish.
The "that's what they thought then" response implies that because science advanced rapidly over the past century or so, it must continue to do so, possibly forever. This is faulty inductive reasoning. A broader view of history suggests that the modern era of explosive progress is an anomaly—the product of a unique convergence of social, economic, and political factors—that must eventually end. Science itself tells us that there are limits to knowledge. Relativity theory prohibits travel or communication faster than light. Quantum mechanics and chaos theory constrain the precision with which we can make predictions. Evolutionary biology reminds us that we are animals, shaped by natural selection not for discovering deep truths of nature but for breeding.
The greatest barrier to future progress in science is its past success. Scientific discovery resembles the exploration of the Earth. The more we know about our planet, the less there is to explore. We have mapped out all the continents, oceans, mountain ranges, and rivers. Every now and then we stumble upon a new species of lemur in an obscure jungle or an exotic bacterium in a deep-sea vent, but at this point we are unlikely to discover something truly astonishing, like dinosaurs dwelling in a secluded cavern. In the same way, scientists are unlikely to discover anything surpassing the Big Bang, quantum mechanics, relativity, natural selection, or genetics.
Just over a century ago, the American historian Henry Adams observed that science accelerates through a positive feedback effect: Knowledge begets more knowledge. This acceleration principle has an intriguing corollary. If science has limits, then it might be moving at maximum speed just before it hits the wall. I am not the only science journalist who suspects we have entered this endgame. "The questions scientists are tackling now are a lot narrower than those that were being asked 100 years ago," Michael Lemonick wrote in Time magazine recently, because "we've already made most of the fundamental discoveries."
Argument: Science is still confronting huge remaining mysteries, like where the universe came from. Other reporters like to point out that there is "No End of Mysteries," as a cover story in U.S. News & World Report put it. But some mysteries are probably unsolvable. The biggest mystery of all is the one cited by Stephen Hawking in A Brief History of Time: Why is there something rather than nothing? More specifically, what triggered the Big Bang, and why did the universe take this particular form rather than some other form that might not have allowed our existence?
Scientists' attempts to solve these mysteries often take the form of what I call ironic science—unconfirmable speculation more akin to philosophy or literature than genuine science. (The science is ironic in the sense that it should not be considered a literal statement of fact.) A prime example of this style of thinking is the anthropic principle, which holds that the universe must have the form we observe because otherwise we would not be here to observe it. The anthropic principle, championed by leading physicists such as Leonard Susskind of Stanford University, is cosmology's version of creationism.
Another example of ironic science is string theory, which for more than 20 years has been the leading contender for a "theory of everything" that explains all of nature's forces. The theory's concepts and jargon have evolved over the past decade, with two-dimensional membranes replacing one-dimensional strings, but the theory comes in so many versions that it predicts virtually everything—and hence nothing at all. Critics call this the "Alice's restaurant problem," a reference to a folk song with the refrain, "You can get anything you want at Alice's restaurant." This problem leads Columbia mathematician Peter Woit to call string theory "not even wrong" in his influential blog of the same title, which refers to a famous put-down by Wolfgang Pauli.
Although Woit echoes the criticisms of string theory I made in The End of Science, he still hopes that new mathematical techniques may rejuvenate physics. I have my doubts. String theory already represents an attempt to understand nature through mathematical argumentation rather than empirical tests. To break out of its current impasse, physics desperately needs not new mathematics but new empirical findings—like the discovery in the late 1990s that the expansion of the universe is accelerating. This is by far the most exciting advance in physics and cosmology in the last decade, but it has not led to any theoretical breakthrough. Meanwhile, the public has become increasingly reluctant to pay for experiments that can push back the frontier of physics. The Large Hadron Collider will be the world's most powerful particle accelerator when it goes online next year, and yet it is many orders of magnitude too weak to probe directly the microrealm where strings supposedly dwell.
To see more discussion on The End of Science, check Horganism, John Horgan's new blog.
