When I was a freshman at Stanford, a physics instructor introduced the topic of relativity by exploding our brains with the following problem:
Take a railroad car straight up 50 miles and then drop it. Given that the Earth is curved, shouldn't the ends of the car fall faster than the middle? Shouldn't the stress this places on the railroad car cause it to break into pieces? And if we think all parts of the railroad car fall at a constant speed, why isn't that evidence that the Earth is flat?
That magnificent morning (I'll explain the adjective shortly) came to mind in the wake of the brouhahabetween the eminent physicist Neil deGrasse Tyson and the rapper B.o.B. over that very question.
To make a long story short, B.o.B. argues that the Earth is indeed flat. He's asserted on Twitter that the rest of us have been "tremendously deceived" and that he is "going up against the greatest liars in history."
For what he seems to view as an act of heroic dissent, the rapper has been mocked endlessly.
I find the whole thing delicious, not only because I'm a fan of dissent. There's occasionally something splendid in the survival of the many fringe positions that real freedom invites.
The history of the flat-Earth idea is fascinating. Although it isn't really true that anybody thought Columbus would sail off the edge of the planet -- even Aristotle knew the Earth was round, and so did the Catholic Church -- the proposition that the Earth can't possibly be a globe has both ancient provenance and continuing vitality.
As Christine Garwood notes in her delightful book, "Flat Earth: History of an Infamous Idea," entire cosmologies and ideologies once rested on the notion. And not always the ideologies you might expect. She credits the "modern public revival of the flat-Earth idea" to Samuel Birley Rowbotham, a radical 19th-century British socialist who wrote under the pseudonym Parallax about what he called "zetetic astronomy."
Parallax told his followers that he had lain on a frozen canal and used a telescope to spot skaters six miles away. Were the Earth curved, he contended, this would have been impossible. But the Earth was flat, he taught.
The North Pole was at the center, and the South Pole was an illusion --- actually there was an icy barrier marking the edges. The sun did not rise or set, but circled in a spiral along the flat Earth, illuminating each part in its turn. He was remarkably clever. He was able to explain everything from eclipses to sea travel. His ideas, Parallax argued, were superior to the Newtonian "juggle and jumble."
Unlike those who claimed to be scientists, he said, he studied what Nature (with a capital N) taught and constructed theories to match, rather than inventing theories that were not testable. His science was democratic, accessible to common men and women (he was very much for sexual equality) through ordinary observation. Truth, he argued, should not be the property of the elite.
The work of Parallax is constantly rediscovered. Later in the 19th century, a British polemicist named John Hampden published pamphlet after pamphlet insisting that neither Christianity nor the British Empire could survive the admission that the world was a sphere. By early in the 20th century, similar ideas were espoused by the creators of utopian communities. In mid-century, the writings of Parallax were picked up by a man named Samuel Shelton, who founded what was originally known as the International Flat Earth Research Society.
The Flat Earth Society, which by happy coincidence celebrates its 60th anniversary this year, continues to thrive in the internet age. On its web page, the group describes itself as "a place for free thinkers and the intellectual exchange of ideas." At this writing, the page is topped with the following headline: "Rapper B.o.B. joins the Flat Earth side!"
Believers in the idea of a flat Earth insist that they are scientists, dissenting from an erroneous and perhaps dangerous consensus. Nothing proves them wrong. Even when photographs of the Earth taken from the moon seemed to show a globe, Greenwood tells us, they had an answer: We were seeing the relativistic effects Einstein predicted. The Earth was actually flat but looked spherical because gravity was bending light itself.
And there seem to be plenty of people out there who believe that the society has it right. You needn't look very hard across the internet to find "proofs" that the Earth is flat. Just as Parallax did, their authors work by inference from observed "facts."
The horizon seen from sea level looks perfectly horizontal, for instance. Or, pilots have no need to correct their flight plans for the curvature of the Earth. These facts, you might answer, are not actually facts - but that is a moot point.
All of which brings us back to why I described my physics prof's teasing as magnificent. Of course we sat down and worked the problem and showed why the railroad car, given reasonable assumptions, might break up as it fell due to friction, but wouldn't break up because of the curvature of the Earth.
Nevertheless, by posing the hypothetical, he signaled to us that every bit of accepted scientific truth should be freshly derived and freshly fought for. We should take nothing for granted. We should constantly inquire.
The form of deductive inquiry in which believers in the flat Earth engage is not really proper scientific method, and it leads them to plenty of conclusions most of us would recognize as wrong. But so what? I'm grateful to live at a time and in a place where they can press their views as widely as they like, and my belief that they're in error is no reason for them to shut up.
The best thing about the game of free speech in a democracy is that everybody has the same right to play.