Replacing paradigms requires open minds

First of two parts

Some people think Thomas Kuhn’s philosophy about scientific paradigms isn’t worth 20 cents.

But many scientists, although they might quibble about the details, know that Kuhn, a physicist-turned-philosopher, was on to something.

For the most part, Kuhn said, scientists practice “normal science.” They work within a particular theoretical framework, or paradigm, in which the big picture is taken for granted and new experiments fill in details. All results are interpreted in terms of the paradigm (or as Kuhn later called it, the “disciplinary matrix”).

Sometimes, though, crises occur. An anomaly — a surprising result — stubbornly resists all efforts to force it to fit into the paradigm. Eventually the anomaly is removed only when a new theory, incompatible with the old paradigm, succeeds in explaining it. Then a new paradigm replaces the old one.

“When the profession can no longer evade anomalies that subvert the existing tradition of scientific practice — then begin the extraordinary investigations that lead the profession at last to a new set of commitments, a new basis for the practice of science,” Kuhn wrote.

Such a shift is what Kuhn called a scientific revolution. In his famous 1962 book The Structure of Scientific Revolutions, he mentioned that novel paradigms usually arise from scientists new to the field. “Almost always the men who achieve these fundamental inventions of a new paradigm have been either very young or very new to the field whose paradigm they change,” Kuhn pointed out.

Sadly, though, in science today the young are generally discouraged from thinking outside the paradigm box.

A prime example (one among many) is cosmology. Young cosmologists or theoretical astrophysicists are indoctrinated with the dogma that the Big Bang was followed by a quick burst of rapid expansion and then a more leisurely expansion that ultimately produced a universe consisting primarily of dark energy and (cold) dark matter. All normal cosmological science is conducted within this framework. And newcomers to the field are reluctant to question it, as Abraham Loeb, a respected Harvard cosmologist, points out in a recent paper.  

Young astrophysicists “spend their most productive years in lengthy postdoctoral positions without job security,” Loeb writes. That “promotes conformism, as postdocs aim to improve their chance of getting a faculty job by supporting the prevailing paradigm of senior colleagues who serve on selection committees.”

He compares cosmologists today to engineers piecing steel rods and bricks together to construct a model of the universe that conforms to standard beliefs, “without pausing to question whether the architecture of the project makes sense when discrepancies between expectations and data are revealed.”

But focusing on the bricks and rods is not the optimum way to create the best blueprint.

“In the scientific quest for the truth, we also need architects (theory makers), not just engineers (theory implementers/testers),” says Loeb. “It is our duty to encourage young researchers to think critically about prevailing paradigms and to come up with simplifying conceptual remedies that take us away from our psychological comfort zone but closer to the truth.”

But such out-of-the-box thinking is not systematically encouraged.

“Conceptual thinkers are becoming an extinct species in the landscape of present-day astrophysics,” Loeb contends. “One would have naively expected scientific activity to be open minded to critical questioning of its architectural design, but the reality is that conservatism prevails within the modern academic setting.”

In other words, the best possible source of fresh ideas — the youngsters whose brains are not yet fossilized by standard dogmas — are ostracized or bullied if they challenge the prevailing paradigms. And scientists wonder why they have so many problems that stubbornly remain so hard to solve.

In fact, there are crises in cosmology today that perfectly fit Kuhn’s recipe for revolutions-in-waiting. Combining quantum physics with gravity, for instance, has been a prime preoccupation of many physicists for decades, with very limited progress. The identity of the dark matter in the universe, which reveals itself only through its gravity, is another decades-old mystery. As I recently related, the mass of the Higgs boson cannot be explained without the presence of other particles that physicists have so far failed to detect.

Besides all these problems, most physicists would cite another as most clearly signaling a crisis. That’s the dark energy permeating space, driving the universe to expand at an accelerating rate. Current physical theory cannot explain the magnitude of that repulsive force. Calculations suggest it should be something like 10122 times stronger than it actually is. If you wrote that number out with all the zeros, you could barely fit it in a tweet. It’s a comparable error to calculating that the size of a subatomic particle should be vastly bigger than the entire universe.

Historically, such crises have typically been resolved with paradigm-busting revolutions.

In 1900, for instance, Lord Kelvin, the preeminent physicist of the 19th century, lamented two crises (he called them “clouds”) threatening the accepted theories of light and heat. One was the lack of evidence for the ether, a medium supposedly perfusing all of space for light and other forms of electromagnetic radiation to vibrate. The other was a mismatch between experiment and the way the molecules of a substance responded to the addition of heat.

In just a few years after Kelvin articulated his concerns, both crises spawned new paradigms. Einstein’s special theory of relativity eliminated the need for an ether, and quantum physics solved the mysteries of molecular responses to heat.

Resolving today’s crises might not require revolutions of that magnitude. But it sure seems to be more and more likely that whatever solutions emerge will have to dash some paradigms. New ideas with revolutionary potential are out there. Recognizing them will require an opening of some cosmological minds.

Follow me on Twitter: @tom_siegfried

Tom Siegfried is a contributing correspondent. He was editor in chief of Science News from 2007 to 2012 and managing editor from 2014 to 2017.

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