Complexity Is the Mother of Simplicity
Science is a simple pleasure--the simpler, the better.
In fact, simplicity is often invoked as the gold standard of a sound theory. As Einstein put it: “Make everything as simple as possible, but not simpler.”
There’s a reason for this beyond sheer elegance: Simplicity implies that one has managed to see through the superficial complexity of a situation straight down to the bone, to distill its pure essence. Einstein was a master at this. What is more simple than the almost babyish equation, E=mc
And yet, contained within those three terms are the fires that fuel stars, the radioactivity that melts rocks and moves the continents and, ultimately, even the alchemy that turns sunlight into children.
Simplicity also suggests a concept is well understood. Research is almost always confusing, but once the truth is grasped, the fog of complexity clears and answers become transparent. It’s easier to see where you’ve been than where you’re going. Even for Sherlock Holmes, only in retrospect were things “elementary, my dear Watson.”
A long legacy of astonishing simplifications leads physicists to suspect that truth is simple. Electric sparks and magnetic attraction, energy and matter, falling apples and shooting stars--all turned out to be but different aspects of the same things.
That’s why present-day physicists scour for further simplifications: Beneath the confusing collection of elementary particles and various forces, is there just one simple underlying entity?
And what about the still mysterious “dark matter” that appears to account for the vast majority of the universe? Ideas for its identity abound, but most require complex interactions among various forces and particles.
Fermilab cosmologist Rocky Kolb, however, is proposing that dark matter may be something far more simple--a consequence of vibrations in the vacuum of the newborn universe that got pulled apart by rapid expansion and became stable particles. (They would be massive versions of theorized particles known as WIMPS, which is why Kolb calls them Wimpzillas.)
These dark-matter particles would be produced by the same established mechanism that created the ripples in space that grew up to be clusters of galaxies. No need for anything fundamentally new.
“It’s appealing to me because it’s not something you invented to make dark matter,” he said. It’s appealing, in other words, for the same reason that Newton’s linking of falling objects and orbiting bodies was appealing: It makes a complex situation simpler.
In truth, simplicity in physics is not so different from the economy we prize in other fields. Writing, for example.
Writers of few words can often say more with less.
Princeton mathematician Ingrid Daubechies once told me that the best thing about becoming a MacArthur Foundation “genius” fellow was the chance to discuss her work with people far outside her field. She was especially pleased, in conversing with a poet, to realize that math and poetry boiled down to much the same exercise. You discover some essential truth, distill it to its pure form and figure out how to communicate it to others.
Wise old sayings accomplish the same trick. “A stitch in time saves nine” is a lot more economical than: “Attack a problem as soon as it arises, because if you wait, you’ll have a much bigger problem on your hands.”
Or consider the rich balance between openness and skepticism contained in the admonition: “Always keep an open mind, but not so open that your brains fall out.” How many pages of prose could say it better?
Of course, there’s no guarantee that truth is simple. Many elegant, simple theories are wrong. And what’s simple in one context may be horrendously complex in another. Fermat’s Last Theorem could be stated in a sentence, but it took hundreds of pages and hundreds of years to prove.
Ironically, as the fundamental understanding becomes simpler, it often seems further removed from complex reality.
When my son was young, he liked to joke: “Atoms for dinner again, Mom?” Everything we eat is composed of protons, neutrons and electrons--but it’s a long way from those three simple particles to pizza and cake.
“There’s a sense in which that’s inevitable,” said MIT physicist Frank Wilczek. “The world doesn’t change. It’s still complicated.” As explanations get simpler, “you need to make longer chains of logic to make contact with the real world.”
Einstein had much the same thought: “Although it sounds paradoxical, we could say: Modern physics is simpler than the old physics and seems, therefore, more difficult and obtuse.”
Still, it’s hard to deny simplicity’s appeal. In a new collection, science fiction writer Arthur C. Clarke relates the story of some young newspaper reporters who once made a bet over who could write the best story in six words.
The winner was a fellow named Hemingway.
He wrote: “For sale. Baby shoes. Never used.”
“Heartbreaking,” says Clarke.
Simply amazing.
