The birth of a new theory: Richard Feynman and his adversaries

Leading physicists discuss their field's most pressing problems
at Shelter Island in April 1947; including, among others, Julian
Schwinger, Richard Feynman and J. Robert Oppenheimer

This post was written on occasion of Richard Feynman's 100th birthday on May 11th and was first published on the website 3 Quarks Daily. It's the second in a pair of articles about two landmark meetings in postwar American physics.

A new theory seldom comes into the world like a fully formed, beautiful infant, ready to be coddled and embraced by its parents, grandparents and relatives. Rather, most new theories make their mark kicking and screaming while their fathers and grandfathers try to disown, ignore or sometimes even hurt them before accepting them as equivalent to their own creations. Ranging from Darwin’s theory of evolution by natural selection to Wegener’s theory of continental drift, new ideas in science have faced scientific, political and religious resistance. There are few better examples of this jagged, haphazard, bruised birth of a new theory as the scientific renaissance that burst forth in a mountain resort during the spring of 1948.

April 2, 1948. Twenty-eight of the country’s top physicists met at the Pocono Manor Hotel near the Delaware Water Gap in Pennsylvania. Kept apart from their first love of fundamental research in physics by the war, they were eager to regroup and rethink the problems which had plagued the heights of their profession before they were called away for war duty to Los Alamos, Cambridge and Chicago.

The listing of participants provides a rare snapshot of one of those hallowed transitions in the history of science, a passing of the torch. Both the old and the new guards were there. The old guard was represented, among others, by Niels Bohr, Paul Dirac and Eugene Wigner – the men who had formulated and then shaped the material world in its quantum mechanical image during the 1920s and 30s. The new guard was represented by Richard Feynman, John Wheeler and Julian Schwinger – the swashbuckling young theorists who wanted to take quantum theory to new heights, even if it meant challenging the old wisdom. J. Robert Oppenheimer who led the conference represented a prophet of the middle ground; a guide joining old hands with new. In retrospect, a clash of worldviews seems almost inevitable.

The problem that was at the forefront of everyone’s attention was the plague of infinities. The infinities had started showing up just a few years after the quantum revolution had burst upon the world. Within a short span of five years or so, between 1925 and 1930, a handful of theorists in their twenties and thirties including Dirac, Werner Heisenberg, Erwin Schrödinger, Max Born and Wolfgang Pauli had completely reworked the foundations of our physical picture of the world. Niels Bohr who along with Albert Einstein and Max Born had kicked off the revolution a decade before was their avuncular godfather; Einstein himself was a reluctant pioneer. The father of quantum mechanics, Max Planck, had showed that energy came only in discrete packets; now these new frontiersmen extended the concept to every physical entity in the universe. The work done by the quantum pioneers revealed a world steeped in probabilities rather than certainties, a world where you could not know the values of even simple parameters like a particle’s position and momentum to infinite precision, a world where particles and waves blurred themselves into each other in a mirage of probability amplitudes and wavefunctions. It was this fundamental ambiguity about what you could know about subatomic entities that led to Einstein’s famous remark about God playing dice.

And yet the theory was accuracy exemplified. Whatever its mathematical and philosophical ambiguities, it kept on providing astonishingly accurate answers to both old and new problems in disparate branches of physics. Whether it was a matter of calculating the frequency of radiation emitted by electrons transitioning in an atom or the resistance of metals to electrical current, quantum theory gave you the right answers, marching in perfect lockstep with numbers from experiment. It seemed to work for virtually every problem you threw it at. Except one.

That puzzle was the interaction between light and matter. It turned up in the simplest of situations, such as calculating the energy of an electron in an atom, and was recognized by the father of quantum field theory, Paul Dirac. Quantum field theory is the most comprehensive description of the world of subatomic particles, and in its simplest sense involves subjecting both particles and the electromagnetic fields which surround them to the rules of quantization. But even a cursory glimpse at the issue made the intractability clear: the energy of a charge in an electromagnetic field – called the ‘self energy’ – is given by the ratio of the strength of the field at various points and the distances between the charge and these points. One calculates the total self-energy by summing up the values at every point. The difficulty is obvious when you think about it: at distances close to zero, you divide by an increasingly smaller number, blowing up the value precipitously. Exactly at the location of the charge, where the distance is zero, the energy becomes infinite; the writers Robert Crease and Charles Mann have described it as a plane being blown to smithereens in its own wake. Clearly this is an absurd result since every energy value which you measure in a real world laboratory is finite.

Starting in about 1930, this problem of infinite self-energy was tackled by many of the most brilliant theoreticians of their time without resolution: Oppenheimer, Heisenberg, the acerbic Wolfgang Pauli and his mild-mannered assistant Victor Weisskopf all described the problem and tried to resolve it in various ways. If anything the picture got even worse; instead of just one infinity, other infinities started rearing their ugly heads like the heads of the mythical Hydra. One of these infinities was pointed out by Dirac. It turns out that during its transition in an atom, an electron can briefly spit out a photon and reabsorb it; this seemingly ex nihilo act of creation is allowed by quantum mechanics as long as it’s done in an exceedingly small amount of time. The problem is that the energy between the electron and this so-called ‘virtual’ photon can be apportioned again in an infinite numbers of ways. If you sum up all these ways you again get the dreaded explosion of infinity.

There seemed to be no end to attempts to exorcising these infinities. Then war intervened, the community of American physicists was drawn up for work on radar and the bomb, and the community of European physicists, many of whom had already fled from Hitler and Mussolini and were scattered across at least two continents, joined them. There the matter of the infinities rested until 1947, when an extraordinary conference of physicists was organized at a small inn off the coast of Long Island near New York City. The Shelter Island conference later went down in history as the conference that kicked off the postwar rejuvenation of particle physics, but in April 1947 it still represented the first stirrings of a revolution. The conference was again chaired by Oppenheimer and included a mix of the old and young guards.

The attention of the participants at Shelter Island was focused on one number of singular importance. Sometimes it takes hard experiment to cut the theoretical Gordian knot. While the theorists had struggled with infinities even before the war, they were galvanized by the experiments of Willis Lamb and his colleague Robert Retherford. Lamb was one of those rare breeds of scientist who are comfortable with both theory and experiment. Combining highly skilled techniques in microwave spectroscopy developed during wartime work on radar with a good understanding of the problems with infinities plaguing quantum field theory, Lamb and Retherford discovered a slight difference in energy between two states of the hydrogen atom at a place where the original Dirac theory predicted no difference. In science revolutions are sometimes engineered by the slightest and most mundane-looking discrepancies in the behavior of matter – Arthur Eddington’s measurement of a tiny shift in the position of the stars predicted by Einstein’s general theory of relativity comes to mind – and the Lamb Shift is as good an example as any of this pivot point in scientific history.

The Lamb Shift is also a telling example of what happens when multiple ideas are in the air, vying with each other for publicity and survival. In the conference Weisskopf had already presented a calculation that could potentially explain the shift, and so had one of the members of the old guard, Hendrik Kramers, who had been Niels Bohr’s assistant. But neither of these efforts got rid of the infinities. It took Hans Bethe with his absolutely mastery of synthesizing different ideas to take the Lamb Shift to its logical conclusion. Nobody surpassed Bethe in his knowledge of multiple branches of physics and his ability to calculate real world answers using the right combination of mathematical techniques and approximations. During a train journey back from Shelter Island, Bethe had the stroke of insight to attempt a calculation of the Lamb Shift using a non-relativistic approximation that ignored effects due to Einstein’s special theory of relativity. In addition, he introduced a physically sensible cutoff for the infinities to get a finite answer. Everyone knew that a correct quantum field would have to include special relativity, so it took some courage on Bethe’s part to attempt a non-relativistic calculation. Strikingly, the result was very close to experiment; 1040 MHz vs 1000 MHz. It still wasn’t the exact answer, but Bethe’s calculation was a shot in the arm, a signal that the theorists’ thinking was on the right track. It was also a fine illustration of how sometimes even a strictly non-realistic, approximate model can guide you in the right direction.

Bethe’s work breathed new life into the work of many others, including Weisskopf and Lamb, both of whom kicked themselves for not thinking about it first. But the biggest impact was on two young members of the group who had already distinguished themselves by their brilliant work during the war – Julian Schwinger and Richard Feynman.

Feynman and Schwinger were two of the earliest products of the American school of theoretical physics. Until the 1930s or so, most American theorists had to go to Europe to learn quantum mechanics at the feet of the masters: Niels Bohr in Copenhagen, Max Born in Göttingen and Arnold Sommerfeld in Munich. In the 30s the center of research started moving to the United States, partly engendered by the exodus of Jewish refugee physicists and partly because of the creation of prominent schools of physics by American physicists themselves. Two of the most prominent schools were Robert Oppenheimer’s at Berkeley and John Archibald Wheeler’s at Princeton. Schwinger came from Oppenheimer’s school; Feynman came from Wheeler’s.

Both Schwinger and Feynman were from New York, but otherwise were very different characters. Feynman was a practical joker who cracked safes, disdained pretension, played the bongos and spoke in colloquial New York City slang. While he had been recognized as a brilliant physicist, he still did not enjoy the star power that Schwinger – a child prodigy who had written his first paper on quantum electrodynamics when he was sixteen – did. Unlike Feynman, the leonine Schwinger wore expensive suits, drove a Cadillac and was the very picture of the distinguished academic. Physicists of the stature of Bethe and Fermi had already paid homage to Schwinger and everyone thought him to be the future. At Shelter Island they had listened to him with reverence; as Oppenheimer put it, “When other physicists do a calculation they want to tell you how they do it; when Schwinger does a calculation he wants to tell you that only he can do it.”

After Shelter Island, the physicists went off to their universities and laboratories, attempting a full calculation of quantum electrodynamics that was relativistic. Schwinger managed to calculate a precise value for the magnetic moment of the electron – a parameter for which comparison between theory and experiment would come to represent the most accurate agreement in all of physics – for the first time in November 1947. Most importantly, the calculation gave a finite answer. One of the elder statesmen of physics, a tough-minded New Yorker named Isidor Rabi, rushed off a note to Bethe: “Schwinger’s calculation is as accurate as yours. God is Great!”.

Feynman was on a completely different track. Working with John Wheeler, he had come up with a novel approach called the path integral approach that included particles traveling backward and forward in time. His bookkeeping technique used a principle familiar from classical mechanics, the principle of least action, that minimized the energy a particle takes in order to travel from A to B. For quantum theory, in Feynman’s hands, one had to consider every single trajectory that the particle would take in order to calculate the most probable one. This so-called 'sum over histories' approach was completely different from anyone else's, although its first trappings had been anticipated by the always prescient Dirac in a paper which Feynman had eagerly read in the Princeton library as a graduate student. Feynman represented his calculations in the form of squiggly and straight lines symbolizing virtual and real particles traveling backward and forward in time. When the Pocono Conference rolled around, he was ready to dazzle his listeners.

Unfortunately Feynman was up against two major obstacles. One was the traditional and hidebound old physics establishment. The other was Julian Schwinger. Schwinger had just given a marathon six-hour talk in which he brought all the formal machinery of mathematical physics to bear on calculating finite answers for electron-photon interactions. His talk was described by some as a virtuoso violin performance, more technique than comprehension. By one account, only Hans Bethe and Enrico Fermi – men who were particularly known for their stamina and powers of concentration – stayed awake and alert enough to follow the entire presentation.

Then Feynman took the podium. Knowing that his listeners would have trouble following the novel derivation of his results, he instead proceeded to simply show them worked out examples. His strategy was understandable, but he was attempting something akin to simply showing worked out examples in a mathematics textbook without showing the underlying theory. For the mandarins of theory who had spent their entire careers trying to take apart and understand all the gory details of how nature worked, this impressionistic-looking display was most unsatisfactory. Immediately they interrupted.

Edward Teller, the Hungarian-born physicist who hadn’t yet achieved the infamous moniker of ‘father of the hydrogen bomb’, thought that Feynman was violating the exclusion principle, a central tenet of physics and chemistry discovered by Wolfgang Pauli that precludes having two electrons with the same energy and spins in the same state. Dirac asked Feynman about a mathematical matrix that carried particle probabilities forward in time. He was wondering about a recondite mathematical property of a matrix called the unitary property that had nonetheless been key in understanding all particle interactions in quantum mechanics. Finally, the elder statesman of physics, the father of them all, Niels Bohr interrupted. Bohr had been impressed at Los Alamos by Feynman’s willingness to brazenly question all authority, including Bohr’s. He now took umbrage at the unfamiliar thicket of squiggles representing particle trajectories. Already in the 1930s, Bohr said in his soft but firm voice, we knew that the classical notion of a trajectory does not make sense in quantum mechanics. Now Feynman seemed to be violating this basic tenet of quantum theory. Bohr strode up to the stage and, standing next to Feynman, speaking in his notorious mumble, delivered a humiliating lecture that seemed to convey Feynman’s lack of understanding of even elementary ideas.

Feynman realized that it was hopeless; Teller was obsessed with a basic fact of quantum mechanics, Dirac was hung up over mathematical formalism, Bohr was still stuck in the 1930s. Clearly his approach was too unconventional and too novel for the old guard. The only way they would listen would be if he laid it all out in an academic paper. History was witnessing the passing of the torch between generations, but for the time being it would have to allow the old generation to win the battle, even if they lost the war. Feynman was undoubtedly on the right track. His new theory had given the right answers for all outstanding problems posed by the new physics. And after his talk, in the next few days, he compared his results with Schwinger’s. These two rivals nonetheless had a healthy respect for each other’s unique approaches, and they realized that were both traversing different trajectories on the mountain of truth.

Within a year Feynman had written up a seminal paper spurred by the disappointment and urgency he witnessed at Pocono. “Space-Time Approach to Quantum Mechanics” would become one of the most important physics papers of the twentieth century. In time, Feynman diagrams would come to dot the pages of the leading physics journals like an art form, much like the native art found on the caves at Lascaux represented its creator’s innermost desires and motivations. And like God bringing, in Schwinger’s words, “computation to the masses”, Feynman would have his own prophet: his colleague Freeman Dyson would unify Schwinger and Feynman’s versions of the promised land and deliver a set of powerful tools that would allow physicists to apply the duo’s techniques to problems in fields ranging from particle physics to astrophysics. And finally, like a voice from the deep, a lonesome letter would come floating to America from the troubled East, where a physicist named Sin-Itiro Tomonaga would have astonishingly worked out Schwinger’s formulation of QED in the isolation and destruction of wartime Japan. In time, QED would provide the most astonishingly accurate between theory and experiment in the history of physics.

But it had all started at Shelter Island and Pocono, where history changed hands and took a new direction, where a thirty year old physicist presented a novel vision; in Dyson’s words, “this wonderful vision of the world as a woven texture of world lines in space and time, with everything moving freely, a unifying principle that would either explain everything or explain nothing.”

Is Big Data shackling mankind's sense of creative wonder?

This is my latest monthly column for the site 3 Quarks Daily. 

Primitive science began when mankind looked upward at the sky and downward at the earth and asked why. Modern science began when Galileo and Kepler and Newton answered these questions using the language of mathematics and started codifying them into general scientific laws. Since then scientific discovery has been constantly driven by curiosity, and many of the most important answers have come from questions of the kind asked by a child: Why is the sky blue? Why is grass green? Why do monkeys look similar to us? How does a hummingbird flap its wings? With the powerful tool of curiosity came the even more powerful fulcrum of creativity around which all of science hinged. Einstein’s imagining himself on a light beam was a thoroughly creative act; so were Ada Lovelace’s thoughts about a calculating machine as doing something beyond mere calculation, James Watson and Francis Crick’s DNA model-building exercise, Enrico Fermi’s sudden decision to put a block of paraffin wax in the path of neutrons.

What is common to all these flights of fancy is that they were spontaneous, often spur-of-the-moment, informed at best by meager data and mostly by intuition. If Einstein, Lovelace and Fermi had paused to reconsider their thoughts because of the absence of hard evidence or statistical data, they might at the very least been discouraged from exploring these creative ideas further. And yet that is what I think the future Einsteins and Lovelaces of our day are in danger of doing. They are in danger of doing this because they are increasingly living in a world where statistics and data-driven decisions are becoming the beginning and end of everything, where young minds are constantly cautioned to not speculate before they have enough data.

We live in an age where Big Data, More Data and Still More Data seem to be all consuming, looming over decisions both big and mundane; from driving to ordering pet food to getting a mammogram. We are being told that we should not make any decision pending its substantiation through statistics and large-scale data analysis. Now, I will be the first one to advocate making decisions based on data and statistics, especially in an era where sloppy thinking and speculation based on incomplete or non-existent data seems to have turned into the very air which the media and large segments of the population breathe. Statistics has especially been found to be both paramount and sorely lacking in making decisions, and books like Daniel Kahneman’s “Thinking Fast and Slow” and Nate Silver’s “The Signal and the Noise” have stressed how humans are intrinsically bad at probabilistic and statistical thinking and how this disadvantage leads to them consistently making wrong decisions. It seems that a restructuring of our collective thinking process that is grounded in data would be a good thing for everyone.

But there are inherent problems with implementing this principle, quite apart from the severe limitations on creative speculation that an excess of data-based thinking imposes. Firstly, except in rare cases, we simply don’t have all the data that is necessary for making a good decision. Data itself is not insight, it’s simply raw material for insight. This problem is seen in the nature of the scientific process itself; in the words of the scientist and humanist Jacob Bronowski, in every scientific investigation we decide where to make a “cut” in nature, a cut that isolates the system of interest from the rest of the universe. Even late into the process, we can never truly know whether the part of the universe we have left out is relevant. Our knowledge of what we have left out is thus not just a “known unknown” but often an “unknown unknown”. Secondly and equally importantly, the quality of the data often takes second stage to its quantity; too many companies and research organizations seem to think that more data is always good, even when more data can mean more bad data. Thirdly, even with a vast amount of data, human beings are incapable of digesting this surfeit and making sure that their decisions include all of it. And fourthly and most importantly, making decisions based on data is often a self-fulfilling prophecy; the hypothesis we form and the conclusions we reach are inherently constrained by the data. We get obsessed with the data that we have and develop tunnel vision, and we ignore the importance of the data that we don’t have. This means that all our results are only going to be as good as the existing data.

Consider a seminal basic scientific discovery like the detection of the Higgs Boson, forty years after the prediction was made. There is little doubt that this was a supreme achievement, a technical tour de force that came about only because of the collective intelligence and collaboration of hundreds of scientists, engineers, technicians, bureaucrats and governments. The finding was of course a textbook example of how everyday science works: a theory makes a prediction and a well-designed experiment confirms or refutes the prediction. But how much more novelty the LHC would have found had the parameters been significantly tweaked, if the imagination of the collider and its operator been set loose? Maybe it would not have found the Higgs then, but it would have discovered something wholly different and unexpected. There would certainly have been more noise, but there would also have been more signal that would have led to discoveries which nobody predicted and which might have charted new vistas in physics. One of the major complaints about modern fundamental physics, especially in areas like string theory, is that it is experiment-poor and theory-rich. But experiments can only find something new when they don’t stay too close to the theoretical framework. You cannot always let prevailing theory dictate what experiments should do.

The success of the LHC in finding the Higgs and nothing but the Higgs points to the self-fulfilling prophecy of data that I mentioned: the experiment was set up to find or disprove the Higgs and the data contained within it the existence or absence of the Higgs. True creative science comes from generating hypotheses beyond the domain of the initial hypotheses and the resulting data. These hypotheses have to be confined within the boundaries of the known laws of nature, but there still has to be enough wiggle room to at least push against these boundaries, if not try to break free of them. My contention is that we are gradually becoming so enamored of data that it is clipping and tying down our wings, not allowing us to roam free in the air and explore daring new intellectual landscapes. It’s very much a case of the drunk under the lamppost, looking for his keys there because that’s where the light is.

A related problem with the religion of “dataism” is the tendency to dismiss anything that constitutes anecdotal evidence, even if it can lead to creative exploration. “Yes, but that’s an n of 1” is a refrain that you must have heard from many a data-entranced statistics geek. It’s important to not regard anecdotal evidence as sacrosanct, but it’s equally wrong in my opinion to simply dismiss it and move on. Isaac Asimov reminded us that great discoveries in science are made when an odd observation or fact makes someone go, “Hmm, that’s interesting”. But if instead, the reaction is going to be “Interesting, but that’s just an n of 1, so I am going to move on”, you are potentially giving up on hidden gems of discovery.

With anecdotal data also comes storytelling which has always been an integral part not just of science but of the human experience. Both arouse our sense of wonder and curiosity; we are left fascinated and free to imagine and explore precisely because of the paucity of data and the lone voice from the deep. Very few scientists and thinkers drove home the importance of taking anecdotal storytelling seriously as well as the late Oliver Sacks. If one reads Sacks’s books, every one of them is populated with fascinating stories of individual men and women with neurological deficits or abilities that shed valuable light on the workings of the brain. If Sacks had dismissed these anecdotes as insufficiently data-rich, he would have missed discovering the essence of important neurological disorders. Sacks also extolled the value of looking at historical data, another source of wisdom that would very easily be dismissed by hard scientists who think all historical data suspect because of its absence of large-scale statistical validation. Sacks regarded historical reports as especially neglected and refreshingly valuable sources of novel insights; in his early days, his insistence that his hospital’s weekly journal club discuss the papers of their nineteenth century forebears was met largely with indifference. But this exploration off the beaten track paid dividends. For instance, he once realized that he had rediscovered a key hallucinogenic aspect of severe migraines when he came across a paper on similar self-reported symptoms by the English astronomer John Herschel, written more than a hundred years ago. A data scientist would surely dismiss Herschel’s report as nothing more than a fluke.

The dismissal of historical data is especially visible in our modern system of medicine which ignores many medical reports of the kind that people like Sacks found valuable. It does an even better job ignoring the vast amount of information contained in the medical repositories of ancient systems of medicines, such as the Chinese and Indian pharmacopeias. Now, admittedly there are a lot of inconsistencies in these reports so they cannot all be taken literally, but neither is the process of ignoring them fruitful. Like all uncertain but potentially useful data, they need to be dug up, investigated and validated so that we can keep the gold and throw out the dross. The great potential value of ancient systems of medicine was made apparent when two years ago, the Nobel Prize for medicine was awarded to Chinese medicinal chemist Tu Youyou for her lifesaving discovery of the antimalarial drug artemisinin. Youyou was inspired to make the discovery when she found a process for low-temperature chemical extraction of the drug in a 1600-year-old Chinese text titled “Emergency Prescriptions Kept Up One’s Sleeve”. This obscure and low-visibility data point would have been certainly dismissed by statistics-enamored medicinal chemists in the West, even if they had known where to find it. Part of recognizing the importance of Eastern systems of medicine consists in recognizing their very different philosophy; while Western medicine seeks to attack the disease and is highly reductionist, Eastern medicine takes a much more holistic approach in which it seeks to modify the physiology of the individual itself. This kind of philosophy is harder to study in the traditional double-blinded, placebo-controlled clinical trial that has been the mainstay of successful Western medicine, but the difficulty of implementing a particular scientific paradigm should not be an argument against its serious study or adoption. As Sacks’s and Youyou’s examples demonstrate, gems of discovery still lie hidden in anecdotal and historical reports, especially in medicine where even today we understand so little about entities like the human brain.

Whether it’s the LHC or medical research, the practice of gathering data and relying only on that data is making us stay close to the ground when we could have been soaring high in the air without these constraints. Data is critical for substantiating a scientific idea, but I would argue that it actually makes it harder to explore wild, creative scientific ideas in the first place, ideas that often come from anecdotal evidence, storytelling and speculation. A bigger place for data leaves increasingly smaller room for authentic and spontaneous creativity. Sadly, today’s publishing culture also rooms little room for pure speculation-driven hypothesizing. As just one example of how different things have become in the last forty years, in 1960 the physicist Freeman Dyson wrote a paper in Science speculating on possible ways to detect alien civilizations based on their capture of heat energy from their parent star. Dyson’s paper contained enough calculations to make it at least a mildly serious piece of work, but I feel confident that in 2017 his paper would probably get rejected from major journals like Science and Nature which have lost their taste for interesting speculation and have become obsessed with data-driven research.

Speculation and curiosity have been mainstays of human thinking since our origins. When our ancestors sat around fires and told stories of gods, demons and spirit animals to their grandchildren, it made the wide-eyed children wonder and want to know more about these mysterious entities that their elders were describing. This feeling of wonder led the children to ask questions. Many of these questions led down wrong alleys, but the ones that survived later scrutiny launched important ideas. Today we would dismiss these undisciplined mental meanderings as superstition, but there is little doubt that they involve the same kind of basic curiosity that drives a scientist. There is perhaps no better example of a civilization that went down this path than ancient Greece. Greece was a civilization full of animated spirits and Gods that controlled men’s destinies and the forces of nature. The Greeks certainly found memorable ways to enshrine these beliefs in their plays and literature, but the same cauldron that imagined Zeus and Athena also created Aristotle and Plato. Aristotle and Plato’s universe was a universe of causes and humors, of earth and water, of abstract geometrical entities divorced from real world substantiation. Both men speculated with fierce abandon. And yet both made seminal contributions to Western science and philosophy even as their ideas were accepted, circulated, refined and refuted for the next two thousand years. Now imagine if Aristotle and Plato had refused to speculate on causes and human anatomy and physiology because they had insufficient data, if they had turned away from imagining because the evidence wasn’t there.

We need to remember that much of science arose as poetic speculations on the cosmos. Data kills the poetic urge in science, an urge that the humanities have recognized for a long time and which science has had in plenty. Richard Feynman once wrote,

“Poets say that science takes away the beauty of the stars and turns them into mere globs of gas atoms. But nothing is ‘mere’. I too can see the stars on a desert night, but do I see less or more? The vastness of the heavens stretches my imagination; stuck on this carousel my little eye can catch one-million-year-old light…What men are poets who can speak of Jupiter as if he were a man, but if he is an immense spinning sphere of methane and ammonia must be silent?”

Feynman was speaking to the sense of wonder that science should evoke in all of us. Carl Sagan realized this too when he said that not only is science compatible with spirituality, but it’s a profound source of spirituality. To realize that the world is a multilayered, many-splendored thing, to realize that everything around us is connected through particles and forces, to realize that every time we take a breath or fly on a plane we are being held alive and aloft by the wonderful and weird principles of mechanics and electromagnetism and atomic physics, and to realize that these phenomena are actually real as opposed to the fictional revelations of religion, should be as much a spiritual experience as anything else in one’s life. In this sense, knowing about quantum mechanics or molecular biology is no different from listening to the Goldberg Variations or gazing up at the Sistine Chapel. But this spiritual experience can come only when we let our imaginations run free, constraining them in the straitjacket of skepticism only after they have furiously streaked across the sky of wonder. The first woman, when she asked what the stars were made of, did not ask for a p value.