Posts Tagged ‘Alan Turing’
Coded references…
Readers will recall the role that Alan Turing and the team at Bletchley Park played in cracking the German Enigma code; some analysts and historians reckon that their work may have shortened World War Two by “not less than two years.”
That code was generated by– and thus cracking it turned on deconstructing and understanding– an Enigma Machine.
Understandably, there were few such machines ever built. And equally understandable, those that survive are extremely expensive collectables. But readers need fear not! Now, thanks to our friends at Instructables, one can convert a “Kid’s Game to an Enigma Machine“:
Step-by-step instructions at Instructables.
Readers might also want to visit Cabinet Magazine‘s wonderful “How to Make Anything Signify Anything,” a profile of American code breaker (and code maker) William Friedman:
By the time he retired from the National Security Agency in 1955, Friedman had served for more than thirty years as his government’s chief cryptographer, and—as leader of the team that broke the Japanese PURPLE code in World War II, co-inventor of the US Army’s best cipher machine, author of the papers that gave the field its mathematical foundations, and coiner of the very term cryptanalysis—he had arguably become the most important code-breaker in modern history.
As we reach for our decoder rings, we might recall that it was on this date in 1884 that the states of Alabama, Georgia, Illinois, Indiana, Kentucky, Mississippi, North Carolina, South Carolina, Tennessee and Virginia, with (at least) 50 tornadoes. Known as “The Enigma Outbreak,” it did an estimated a total of $3–4 million in tornado damage (in 1884 dollars; plus an unknown amount of flood and other damage), destroying over 10,000 structures.
Photo: © D. Burgess / NOAA (source)
Knowing what’s unknowable…
We’ve known for quite awhile that there’s a limit to what we can know… Werner Heisenberg discovered that improved precision regarding, say, an object’s position inevitably degraded the level of certainty of its momentum. Kurt Gödel showed that within any formal mathematical system advanced enough to be useful, it is impossible to use the system to prove every true statement that it contains. And Alan Turing demonstrated that one cannot, in general, determine if a computer algorithm is going to halt.
Now David Wolpert, a physicist working as a computer scientist at NASA Ames, has elaborated on that limit. As Scientific American reports, Wolpert’s work show’s that
…the universe lies beyond the grasp of any intellect, no matter how powerful, that could exist within the universe. Specifically, during the past two years, he has been refining a proof that no matter what laws of physics govern a universe, there are inevitably facts about the universe that its inhabitants cannot learn by experiment or predict with a computation. Philippe M. Binder, a physicist at the University of Hawaii at Hilo, suggests that the theory implies researchers seeking unified laws cannot hope for anything better than a “theory of almost everything.”
…
Wolpert proves that in any such system of universes, quantities exist that cannot be ascertained by any inference device inside the system. Thus, the “demon” hypothesized by Pierre-Simon Laplace in the early 1800s (give the demon the exact positions and velocities of every particle in the universe, and it will compute the future state of the universe) is stymied if the demon must be a part of the universe.
Researchers have proved results about the incomputability of specific physical systems before. Wolpert points out that his result is far more general, in that it makes virtually no assumptions about the laws of physics and it requires no limits on the computational power of the inference device other than it must exist within the universe in question. In addition, the result applies not only to predictions of a physical system’s future state but also to observations of a present state and examining a record of a past state.
The theorem’s proof, similar to the results of Gödel’s incompleteness theorem and Turing’s halting problem, relies on a variant of the liar’s paradox—ask Laplace’s demon to predict the following yes/no fact about the future state of the universe: “Will the universe not be one in which your answer to this question is yes?” For the demon, seeking a true yes/no answer is like trying to determine the truth of “This statement is false.” Knowing the exact current state of the entire universe, knowing all the laws governing the universe and having unlimited computing power is no help to the demon in saying truthfully what its answer will be.
Read the full story here.
As we reconcile ourselves to incompleteness, we might console ourselves that it was on this date in 1929 that the Hollywood Sign was officially dedicated in the hills above Hollywood, Los Angeles. It originally read “Hollywoodland ,” but the four last letters were dropped after renovation in 1949. Recently threatened with demolition for want of maintenance funds, the icon was saved by a donation from Hugh Hefner.
The sign in it’s original form, as seen from Beachwood Canyon (source)
Take two, and I promise that you won’t feel like calling me in the morning…
From the good folks at Pill Talk, a reminder that today’s illicit drugs were yesterday’s featured pharmaceuticals… From Black Beauties marketed as a weight loss aid to Bayer’s ad for Heroin (“the sedative for coughs”), readers can see them all here. (And for more on Heroin’s companion in the Bayer catalog, aspirin, see the almanac portion of the post here.)
As we realize that we still have our coughs but don’t really care, we might remark that today is the birthday of not one but two extraordinary mathematicians: Gottfried Wilhelm Leibniz (1646; variants on his date of birth due to calendar changes), the German philosopher, scientist, mathematician, diplomat, librarian, lawyer, co-inventor, with Newton, of The Calculus, and “hero” of Neal Stephenson’s Baroque Trilogy… and Alan Turing (1912), British mathematician, computer science pioneer (inventor of the Turing Machine, creator of “the Turing Test” and inspiration for “The Turing Prize”) and cryptographer (leading member of the team that cracked the Enigma code during WWII). Go figure…
Liebnitz (source: UNC)
Turing (source: Univ. of Birmingham)
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