End of Science: Facing the Limits of Knowledge in the Twilight of the Scientific Age

It was in the summer of 1989, during a trip to upstate New York, that I began to think seriously about the possibility that science, pure science, might be over.  I had flown to the University of Syracuse to interview Roger Penrose, a British physicist who was a visiting scholar there.  Before meeting Penrose, I had struggled through galleys of his dense, difficult book, The Emperor's New Mind, which to my astonishment became a best-seller several months later, after being praised in the New York Times Book Review.  In the book, Penrose cast his eye across the vast panorama of modern science and found it wanting.  This knowledge, Penrose asserted, for all its power and richness, could not possibly account for the ultimate mystery of existence, human consciousness.

The key to consciousness, Penrose speculated, might be hidden in the fissure between the two major theories of modern physics: quantum mechanics, which describes electromagnetism and the nuclear forces, and general relativity, Einstein's theory of gravity.  Many physicists, beginning with Einstein, had tried and failed to fuse quantum mechanics and general relativity into a single, seamless "unified" theory.  In his book, Penrose sketched out what a unified theory might look like and how it might give rise to thought.  His scheme, which involved exotic quantum and gravitational effects percolating through the brain, was vague, convoluted, utterly unsupported by evidence from physics or neuroscience.  But if it turned out to be in any sense right, it would represent a monumental achievement, a theory that in one stroke would unify physics and solve one of philosophy's most vexing problems, the link between mind and matter.  Penrose's ambition alone, I thought, would make him an excellent subject for a profile in Scientific American, which employed me as a staff writer.

When I arrived at the airport in Syracuse, Penrose was waiting for me.  He was an elfin man, capped with a shock of black hair, who seemed simultaneously distracted and acutely alert.  As he drove us back to the Syracuse campus, he kept wondering aloud if he was going in the right direction.  He seemed awash in mysteries.  I found myself in the disconcerting position of recommending that he take this exit, or make that turn, although I had never been in Syracuse before.  In spite of our combined ignorance, we managed to make our way without incident to the building where Penrose worked.  On entering Penrose's office we discovered that a colleague had left a brightly colored aerosol can labeled Superstring on his desk.  When Penrose pushed the button on the top of the can, a lime green spaghetti-like strand shot across the room.

Penrose smiled at this little insider's joke.  Superstring is the name not only of a child's toy, but also of an extremely small and extremely hypothetical stringlike particle posited by a popular theory of physics.  According to the theory, the wriggling of these strings in a 10-dimensional hyperspace generates all the matter and energy in the universe and even space and time.  Many of the world's leading physicists felt that superstring theory might turn out to be the unified theory they had sought for so long; some even called it a theory of everything.  Penrose was not among the faithful.  "It couldn't be right," he told me.  "It's just not the way I'd expect the answer to be."  I began to realize, as Penrose spoke, that to him "the answer" was more than a mere theory of physics, a way of organizing data and predicting events.  He was talking about The Answer: the secret of life, the solution to the riddle of the universe.

Penrose is an admitted Platonist.  Scientists do not invent the truth; they discover it.  Genuine truths exude a beauty, a rightness, a self-evident quality that gives them the power of revelation.  Superstring theory did not possess these traits, in Penrose's mind.  He conceded that the "suggestion" he set forth in The Emperor's New Mind--it did not merit the term theory yet, he admitted--was rather ungainly.  It might turn out to be wrong, certainly in its details.  But he felt sure that it was closer to the truth than was superstring theory.  In saying that, I asked, was Penrose implying that one day scientists would find The Answer and thus bring their quest to an end?

Unlike some prominent scientists, who seem to equate tentativity with weakness, Penrose actually thinks before he responds, and even as he responds.  "I don't think we're close," he said slowly, squinting out his of office window, "but it doesn't mean things couldn't move fast at some stage."  He cogitated some more. "I guess this is rather suggesting that there is an answer," he continued, "although perhaps that's too pessimistic."  This final comment stopped me short.  What is so pessimistic, I asked, about a truth seeker thinking that the truth is attainable?  "Solving mysteries is a wonderful thing to do," Penrose replied.  "And if they were all solved, somehow, that would be rather boring."  Then he chuckled, as if struck by the oddness of his own words.

Long after leaving Syracuse, I mulled over Penrose's remarks.  Was it possible that science could come to an end?  Could scientists, in effect, learn everything there is to know?  Could they banish mystery from the universe?  It was hard for me to imagine a world without science, and not only because my job depended on it.  I had become a science writer in large part because I considered science--pure science, the search for knowledge for its own sake--to be the noblest and most meaningful of human endeavors.  We are here to figure out why we are here.  What other purpose is worthy of us?

I had not always been so enamored of science.  In college, I passed through a phase during which literary criticism struck me as the most thrilling of intellectual endeavors.  Late one night, however, after too many cups of coffee, too many hours spent slogging through yet another interpretation of James Joyce's Ulysses, I had a crisis of faith.  Very smart people had been arguing for decades over the meaning of Ulysses.  But one of the messages of modern criticism, and of modern literature, was that all texts are "ironic": they have multiple meanings, none of them definitive. Oedipus Rex, The Inferno, even the Bible are in a sense "just kidding," not to be taken too literally.  Arguments over meaning can never be resolved, since the only true meaning of a text is the text itself.  Of course, this message applied to the critics, too.  One was left with an infinite regress of interpretations, none of which represented the final word.  But everyone still kept arguing!  To what end?  For each critic to be more clever, more interesting, than the rest? It all began to seem pointless.

Although I was an English major, I took at least one course in science or mathematics every semester.  Working on a problem in calculus or physics represented a pleasant change of pace from messy humanities assignments; I found great satisfaction in arriving at the correct answer to a problem.  The more frustrated I became with the ironic outlook of literature and literary criticism, the more I began to appreciate the crisp, no-nonsense approach of science.  Scientists have the ability to pose questions and resolve them in a way that critics, philosophers, historians cannot.  Theories are tested experimentally, compared to reality, and those found wanting are rejected.  The power of science cannot be denied: it has given us computers and jets, vaccines and thermonuclear bombs, technologies that, for better or worse, have altered the course of history.  Science, more than any other mode of knowledge--literary criticism, philosophy, art, religion--yields durable insights into the nature of things.  It gets us somewhere.  My mini-epiphany led, eventually, to my becoming a science writer.  It also left me with this criterion for science: science addresses questions that can be answered, at least in principle, given a reasonable amount of time and resources.

Before my meeting with Penrose, I had taken it for granted that science was open-ended, even infinite.  The possibility that scientists might one day find a truth so potent that it would obviate all further investigations had struck me as wishful thinking at best, or as the kind of hyperbole required to sell science (and science books) to the masses.  The earnestness, and ambivalence, with which Penrose contemplated the prospect of a final theory forced me to reassess my own views of science's future.  Over time, I became obsessed with the issue.  What are the limits of science, if any?  Is science infinite, or is it as mortal as we are?  If the latter, is the end in sight?  Is it upon us?

After my original conversation with Penrose, I sought out other scientists who were butting their heads against the limits of knowledge: particle physicists who dreamed of a final theory of matter and energy; cosmologists trying to understand precisely how and even why our universe was created; evolutionary biologists seeking to determine how life began and what laws governed its subsequent unfolding; neuroscientists probing the processes in the brain that give rise to consciousness; explorers of chaos and complexity, who hoped that with computers and new mathematical techniques they could revitalize science. I also spoke to philosophers, including some who allegedly doubted whether science could ever achieve objective, absolute truths.  I wrote articles about a number of these scientists and philosophers for Scientific American.

When I first thought about writing a book, I envisioned it as a series of portraits, warts and all, of the fascinating truth seekers and truth shunners I have been fortunate enough to interview.  I intended to leave it to readers to decide whose forecasts about the future of science made sense and whose did not.  After all, who really knew what the ultimate limits of knowledge might be?  But gradually, I began to imagine that I knew; I convinced myself that one particular scenario was more plausible than all the others.  I decided to abandon any pretense of journalistic objectivity and write a book that was overtly judgmental, argumentative, and personal.  While still focusing on individual scientists and philosophers, the book would present my views as well.  That approach, I felt, would be more in keeping with my conviction that most assertions about the limits of knowledge are, finally, deeply idiosyncratic.

It has become a truism by now that scientists are not mere knowledge acquisition machines; they are guided by emotion and intuition as well as by cold reason and calculation.  Scientists are rarely so human, I have found, so at the mercy of their fears and desires, as when they are confronting the limits of knowledge.  The greatest scientists want, above all, to discover truths about nature (in addition to acquiring glory, grants, and tenure and improving the lot of humankind); they want to know.  They hope, and trust, that the truth is attainable, not merely an ideal or asymptote, which they eternally approach.  They also believe, as I do, that the quest for knowledge is by far the noblest and most meaningful of all human activities.

Scientists who harbor this belief are often accused of arrogance.  Some are arrogant, supremely so.  But many others, I have found, are less arrogant than anxious.  These are trying times for truth seekers.  The scientific enterprise is threatened by technophobes, animal-rights activists, religious fundamentalists, and, most important, stingy politicians.  Social, political, and economic constraints will make it more difficult to practice science, and pure science in particular, in the future.

Moreover, science itself, as it advances, keeps imposing limits on its own power.  Einstein's theory of special relativity prohibits the transmission of matter or even information at speeds faster than that of light; quantum mechanics dictates that our knowledge of the microrealm will always be uncertain; chaos theory confirms that even without quantum indeterminacy many phenomena would be impossible to predict; Kurt Gödel's incompleteness theorem denies us the possibility of constructing a complete, consistent mathematical description of reality.  And evolutionary biology keeps reminding us that we are animals, designed by natural selection not for discovering deep truths of nature, but for breeding.

Optimists who think they can overcome all these limits must face yet another quandary, perhaps the most disturbing of all.  What will scientists do if they succeed in knowing what can be known?  What, then, would be the purpose of life?  What would be the purpose of humanity?  Roger Penrose revealed his anxiety over this dilemma when he called his dream of a final theory pessimistic.

Given these troubling issues, it is no wonder that many scientists whom I interviewed for this book seemed gripped by a profound unease.  But their malaise, I will argue, has another, much more immediate cause.  If one believes in science, one must accept the possibility--even the probability-- that the great era of scientific discovery is over.  By science I mean not applied science, but science at its purest and grandest, the primordial human quest to understand the universe and our place in it.  Further research may yield no more great revelations or revolutions, but only incremental, diminishing returns.

The Anxiety of Scientific Influence

In trying to understand the mood of modern scientists, I have found that ideas from literary criticism can serve some purpose after all.  In his influential 1973 essay, The Anxiety of Influence, Harold Bloom likened the modern poet to Satan in Milton's Paradise Lost.  Just as Satan fought to assert his individuality by defying the perfection of God, so must the modern poet engage in an Oedipal struggle to define himself or herself in relation to Shakespeare, Dante, and other masters.  The effort is ultimately futile, Bloom said, because no poet can hope to approach, let alone surpass, the perfection of such forebears.  Modern poets are all essentially tragic figures, latecomers.

Modern scientists, too, are latec...