Free Broca's Brain by Carl Sagan

Elizabeth Barrett Browning. The “manifestations” brought about by the Fox sisters are the origins of modern spiritualism, the belief that by some special effort of will a few gifted people are able to communicate with the spirits of the dead. Keene’s associates owe a substantial debt to the Fox sisters.
    Forty years after the first “manifestations,” provoked by an uneasy conscience, Margaret Fox produced a signed confession. The raps were made—in a standing position with no apparent effort or movement—by cracking the toe and ankle joints, very much like cracking knuckles. “And that is the way we began. First, as a mere trick to frighten mother, and then, when so many people came to see us children, we were ourselves frightened, and for self-preservation forced to keep it up. No one suspected us of any trick because we were such young children. We were led on by my sister purposely and by mother unintentionally.” The eldest sister, who organized their tours, seems to have been fully conscious of the fraud. Her motive was money.
    The most instructive aspect of the Fox case is not that so many people were bamboozled; but rather that after the hoax was confessed, after Margaret Fox made a public demonstration, on the stage of a New Yorktheater, of her “preternatural big toe,” many who had been taken in still refused to acknowledge the fraud. They pretended that Margaret had been coerced into the confession by some rationalist Inquisition. People are rarely grateful for a demonstration of their credulity.

THE CARDIFF GIANT
     
    IN 1869 THE FIGURE of a larger-than-life stone man was unearthed by a farmer “while digging a well” near the village of Cardiff in western New York. Clergymen and scientists alike asserted that it was a fossilized human being from ages past, perhaps a confirmation of the Biblical account: “There were giants in those days.” Many commented on the detail of the figure, seemingly far finer than a mere artisan could have carved from stone. Why, there were even networks of tiny blue veins. But others were less impressed, including Andrew Dickson White, the first president of Cornell University, who declared it to be a pious fraud, and execrable sculpture to boot. A meticulous examination then revealed it to be of very recent origin, whereupon it emerged that the Cardiff Giant was merely a statue, a hoax engineered by George Hull of Binghamton, who described himself as “tobacconist, inventor, alchemist, atheist,” a busy man. The “blue veins” were a natural pattern in the sculpted rock. The object of the deception was to fleece tourists.
    But this uncomfortable revelation did not faze the American entrepreneur P. T. Barnum, who offered $60,000 for a three-month lease on the Cardiff Giant. When Barnum failed to secure it for traveling exhibition (the owners were making too much money to give it up), he simply had a copy made and exhibited
it
, to the awe of his customers and the enrichment of his pocketbook. The Cardiff Giant that most Americans have seen is this copy. Barnum exhibited a fake fake. The original is today languishing at the Farmer’s Museum in Cooperstown, New York. Both Barnum and H. L. Mencken are said to have made the depressingobservation that no one ever lost money by underestimating the intelligence of the American public. The remark has worldwide application. But the lack is not in intelligence, which is in plentiful supply; rather, the scarce commodity is systematic training in critical thinking.

CLEVER HANS, THE MATHEMATICAL HORSE
     
    IN THE EARLY YEARS of the twentieth century there was a horse in Germany who could read, do mathematics and exhibit a deep knowledge of world political affairs. Or so it seemed. The horse was called Clever Hans. He was owned by Wilhelm von Osten, an elderly Berliner whose character was such, everyone said, that fraud was out of the question. Delegations of distinguished scientists viewed the equine marvel and pronounced