Scientific wager

A scientific wager is a wager whose outcome is settled by scientific method. They typically consist of an offer to pay a certain sum of money on the scientific proof or disproof of some currently uncertain statement. Some wagers have specific date restrictions for collection, but many are open. Wagers occasionally exert a powerful galvanizing effect on society and the scientific community.

Notable scientists active in the making of scientific wagers include Stephen Hawking, Richard Feynman. Stanford Linear Accelerator has an open book containing about 35 bets in particle physics dating back to 1980; many are still unresolved.

Famous scientific wagers

• In 1959, Richard Feynman bet $1000 that noone could construct a motor no bigger than 1/64 of an inch on a side. He lost the bet when Bill McLennan, using radio ham skills, constructed such a motor. Feynman had never formalized the bet because he couldn't define his terms sufficiently precisely, but paid up anyway; Feynman is also on record as saying that he was disappointed with the outcome because he had hoped his reward would stimulate some new fabrication technology, but McLellan's motor used only existing techniques. Physicist Philip Ball, writing in Nature Materials, discusses this episode and concludes "Do we, like Feynman, always underestimate what our current technologies can achieve?"
• In 1975, cosmologist Stephen Hawking bet fellow cosmologist Kip Thorne a subscription to Penthouse magazine (the loser would get it mailed to his home) that a Cygnus X-1 would turn out not to be a black hole. It was, so Hawking lost. It has been said that Hawking hoped to lose the bet as so much of his own work depended upon the existence of black holes. For Hawking, then, the bet was a type of insurance.
• In 1997 Stephen Hawking and Kip Thorne made a bet with John Preskill on the ultimate resolution of the apparent contradiction between Hawking radiation resulting in loss of information, and a requirement of quantum mechanics that information cannot be destroyed. Hawking and Thorne bet that information must be lost in a black hole; Preskill bet that it must not. The formal wager is: "When an initial pure quantum state undergoes gravitational collapse to form a black hole, the final state at the end of black hole evaporation will always be a pure quantum state". The stake is an encyclopedia of the winner's choice, from which "information can be recovered at will".
• In 1980, biologist Paul R. Ehrlich bet economist Julian Simon that the price of a portfolio of $200 of each of five mineral commodities (copper, chromium, nickel, tin, and tungsten) would rise over the next 10 years. He lost: by 1990, the prices had fallen to $576. See also: Wager between Julian Simon and Paul Ehrlich.
• In 1870, Alfred Russel Wallace bet John Hampden, a believer in the flat-Earth theory, that he (Wallace) could prove the flat Earth hypothesis incorrect. The sum staked was £500 (then worth a great deal more than now). A test, involving a stretch of the Old Bedford Canal, in London, was agreed on: Wallace measured the curvature of the canal's surface using two markers separated by about five kilometres and suspended at equal heights above the water's surface. Using a telescope mounted 5km from one of the markers, Wallace established that the nearer one appeared to be the higher of the two. An independent referee agreed that this showed the Earth's surface to curve away from the telescope, and so Wallace received his money. However, Hampden never accepted the result and made increasingly unpleasant threats to Wallace.
• In 1684, Christopher Wren announced that he would give a book worth 40 shillings to anyone who could deduce Kepler's laws from the inverse-square law. Isaac Newton's musings on this problem eventually grew into his Principia. However, Newton was too late to qualify for the book. Historian Alan Shapiro has stated that this episode was "undoubtedly one of the most crucial wagers in scientific history".

See also

• The efforts of photographer Eadweard Muybridge to capture the motion of a galloping horse were not part of a wager, contrary to popular opinion.
• Pascal's wager is not a wager in the sense used in this article.