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Stu Savory's Blog
 http://www.savory.de/blog.htm De maximis non curat blog ;-) | |
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Friday, June 29, 2007
How the TARDIS works
Who knows how the TARDIS works? Yes, Who does! And so do I ;-) Certainly my UK readers, and perhaps some of my US and Australian readers, will have heard of Dr.Who, a TV science fiction series which the BBC have been broadcasting since 1963 (for 44 years!) It is the longest-running science fiction television series in the world (sez Guinness). The TARDIS (latin tardis = late, an early BBC pun) is the time machine
(and spacecraft) in the British SF TV programme Doctor Who.
When the TARDIS is winding up its spring to 'take off', the drive mechanism emits a
cyclic wheezing, groaning, pumping noise. And now the time has come of late(sic!)
for me to explain this noise to my
faith Of course the version of the TARDIS that you build does not necessarily have to look like a UK police box. It could look like a huge cigar, like the flying saucers seen over Guernsey island last week. But remember, an ex MoD (UK Ministry of Defence) chief - who has seen all the classified material - warns is that 'Aliens could attack at any time' (sic!). Both reports fail to consider that sightings may be of amateur attempts to build a TARDIS by people who have read this blog's springtime explanation ;-) The TARDIS usually travels by dematerialising in one spot, traversing the time vortex, and then rematerialising at its destination, without physically travelling through the intervening space. Let me explain today by using a simple analogy how this is done. Why am I using an analogy? Well I estimate that over 99% of my readership will not be able to cope with the maths of doing tensor calculus in five dimensions. We are used to thinking of our universe in 4D, that is 3D space and time as the 4th dimension (pace Einstein). But really we exist in 5D, space,time and thingy (for want of a better name). The better name is actually "a type II Randall-Sundrum braneworld gravity model". This theory holds that the visible universe is a membrane (hence "braneworld") embedded within a larger universe, much like a strand of filmy seaweed floating in the ocean. The "braneworld universe" has five dimensions -- four spatial dimensions plus time -- compared with the four dimensions -- three spatial, plus time -- laid out in Einstein's General Theory of Relativity. Scientists Charles R. Keeton of Rutgers and Arlie O. Petters at Duke and Rutgers universities have developed a mathematical framework they say will enable astronomers to test a new five-dimensional theory that competes with Einstein's General Theory of Relativity. If you want more details than I can give in the short space of this blog, may I suggest you read Paul Wesson's book "Five-dimensional Physics: Classical And Quantum Consequences of Kaluza-klein Cosmology". Excellent book and easy on the maths. But if you want to run through the maths of 4D relativistic stress tensors before redoing the tensor calculus in 5D to see how much easier they are in 5D, then I'd point you to Stefan Waner's online lectures which he has kept very simple :-) Also, Rajagopal and his cohorts took advantage of a 1997 discovery by particle physicist Juan Maldacena at the Institute for Advanced Study in Princeton, N.J., that a form of string theory in four dimensions of space - one more than people are used to - is equivalent to a Quantum-Chromo-Dynamical(QCD)-like theory in three space dimensions. When forces become strong in this QCD-like theory, they become weak in string theory, offering an easier way to do calculations related to quarks. Why can't we see the 5th dimension, at right angles to the other four? The 5th dimension may be thought of as 'rolled up' with a diameter less than the Planck distance (less than the wavelengths of light) and so is imperceptable to our senses.
Be that as it may, I want to use the simple analogy of a coil spring. The 3D space which we are used to is analagous to a cross section through the metal wire. As time progresses we move along the metal coil and our 3D world appears to be moving linearly through time. But in 5D reality, the time-axis is 'coiled up' as shown in this coiled spring analogy. When the TARDIS is winding up to 'take off', the drive mechanism emits a cyclic wheezing, groaning, pumping noise. What is happening? The TARDIS drive mechanism is (in this analogy) compressing and releasing the 5D coilspring. A slight energy leak (remember this a defective Model 40 TARDIS we're talking about) from this cyclical pumping is what makes the wheezing-pumping noise. When the TARDIS drive mechanism has got into sync with the 5D of reality, the coils can touch one another. When this happens, the TARDIS can - with a minimal expenditure of energy - 'jump' to a neighbouring coil. From the 4D point of view which we have, the TARDIS has just travelled through time. As I said before, as seen from a mere 4D point of view, the TARDIS travels by dematerialising in one spot, traversing the time vortex, and then rematerialising at its destination, without physically travelling through the intervening space. But it has really just jumped across the coils of the real 5D space-time-thingy orbifold. Double trips back and forth give rise to a number of interesting and quite useful phenomena. Coming back to a slightly different spatial position but at the same time has you being in two places at the same time : teleportation. Instant escapology. Do it twice and you could teleport into a bank-safe (e.g. Fort Knox), rob the bank, and teleport out again with your ill-gotten gains. Or free your friends from jail. Instant alibis too. Coming back to a slightly different temporal position would be a bit like reincarnation : gives a whole new meaning to "shuffling off this mortal coil" ;-) Now this analogy is not perfect (if it were, it would BE reality, by Occam's razor), because the TARDIS can jump across any number of coils. But always offset by an integral number of whole coil diameters. This is a quantum effect of time travel as done by the Time Lords. The granularity of the coils of time-jumps is also not as regular as suggested by this coilspring picture. Try to think of a progressive coilspring instead, where the coils have variable spacing (excuse the temporal pun). Now Wikipaedia claims that in order for the temporal drive to work, the TARDIS needs a crystal power source from within the TARDIS, charged by the Doctor's life force, mercury (used in its fluid links), the rare ore Zeiton 7 and "artron energy." None of this is true. You merely need the cyclical coilspring compressor described above (in its five dimensional form) and - for your edification and for good taste - a pinch of salt.
Wednesday, June 27, 2007
yellA hsaW raC eht hguorht yaw gnorW ;-)
 The local press has reported a strange car accident recently, a collision caused by a blonde woman driving through a Car Wash Alley in the wrong direction! You know the kind, where a bar hooks in behind the front wheels and pulls your car through the various wash, foam, rinse, wax, and dry stations inside the alley? Admittedly, the one at the Südring shopping centre does not have a No-Entry sign outside the Exit, so I suppose she could be excused, except that she hit the car of a young man going through the Car Wash Alley the right way :-( She is reported by the police investigating the accident as saying that driving the wrong way through a car wash is "like having great sex". Huh? Come again? My imagination ran riot as I tried to imagine the policeman taking her statement:- Blonde : "Driving
the wrong way through a car wash is like having great sex."
Sunday, June 24, 2007
In Memoriam : Mandarin Meg, one year gone
A year has passed since our dear blogfriend Michelle Goodrich passed into the realms beyond mortal ken. Let us hope she has an easier time next time around (Meg was a Buddhist). She certainly collected enough good Karma on the last pass. I ask you to re-read the obituary I wrote this weekend a year ago. Michelle, known as Meg to her friends (and there were many), had her own way of sharing link-love. It was a quilt, pointing to the blogs she read regularly. In her memory, I reproduce her quilt of bloggers here. We miss you, dear Michelle. 
Friday, June 22, 2007
For Wendy Templeton ;-)
B logfriend Wendy Templeton from Hong Kong has been telling me what a sub-editor does. They're there to tidy up the mess that reporters and other authors submit to newspapers and magazines and make the author look better than he/she thinks he/she is. They also catch factual errors and correct spelling and grammatical errors too, e.g. "you still have to watch out for people singing contracts, large companies raping a first-half profit of US$24 etc." And so this photo today is dedicated to Wendy by way of thanks for her explanation . . . . . . up until which I had always thought that sub-editors were people who wrote the rosters, daily orders, etc on the noticeboards in Her Majesty's U-boats ;-) Am I to assume that a subservient isn't the captain's batman in a submarine either? Wendy tells me that : "I saw a documentary once on the English language and in one bit they interviewed a bunch of editors from The Sun. They were given synopses of some classics and were asked to come up with front page headlines for them. My favourite was for Oedipus Rex: "SEX WITH MUM WAS BLINDING!". Presumably it is the sub-editors of page 3 of The Sun who are responsible for keeping everything there "ship-shape and Bristols fashion" ;-)
Wednesday, June 20, 2007
Time and time again...I remember correctly, tomorrow was the day on which Charles invented the Time Machine again(?) for the first time . . .By now an old man, Charles heaved a sigh of relief as he completed his life-long dream of building a quantum-effect time-machine, because he knew he was now effectively immortal. Nothing like H.G.Wells time machine, Charles' discovery was a small sleek black box to be attached to a 6-point sky-diver's belt that one merely strapped on so there was no chance of being separated from it. Having a black sense of humour, Charles had lovingly inscribed it 'property of Herr Schoedinger' before welding the box shut. The single bidirectional lever was labelled 'Past' - 'Future' with a central notch labelled 'Now'. Whatever that meant, Charles thought wryly. Charles made sure the calender on the wall and the solar-powered wall clock were both set correctly, put out food for the cat (who seemed to have disappeared) and then donned the belt. He clipped his video-camera onto its chestplate mount and turned it on. Then he rechecked his calculations on how far he would need to move the lever forward, having decided to head some 7000 years into the future. Taking a deep breath (why?) he moved the lever resolutely forward. There was short quantum flicker as the world aged around him, then it stopped. Oh!! He appeared to be caught in some kind of sticky retaining web, like a fly on flypaper. Strange humanoid beings, winged and glowing, were watching him, and inspected the box with interest. "Welcome Mr. Schroedinger to 9000 AD. Call me Azrael. You are the first and last time-traveller to visit the future. You see, time-travel into the future is banned by intergalactic convention, to avoid any changes in the flow of events. And of course this law applies to you too, even if you invented your machine 'before' the law came into force. Whatever that means..." the being added. Then he reached over gently and moved Charles' lever into the 'Now' position. There was short quantum flicker again as the world retro-flowed around him and Charles re-appeared in his room. The calender was unchanged and the clock had moved on a bare 30 secs, about the elapsed time that he had spent in 9000 AD, Charles thought. After regaining his composure, Charles thought about his options. After all, the creature had said that time travel into the future was forbidden, but the past open to him. Charles perked up. He thought about his destination : when should it be? He could go back to his birth, he could go back to Christ's birth, disguising himself as a shepherd, to look in His face. What had the creature said about changing the course of events? Perhaps that was not a good idea. Go back to visit Adam and Eve? Perhaps that was not a good idea either, he might turn out to be the 'snake'! And when was that anyway? He remembered that Irish archbishop James Ussher had determined that the world was created in to the night preceding October 23, 4004 BC. Charles laughed at the primitive beliefs. No, Charles decided he had always wanted to see the dinosaurs, epecially Tyrannosaurus Rex, 200 million years ago. Charles did the calculations on how far he would need to move the logarithmically scaled lever backward, having decided to head some 200 million years into the past. Taking a deep breath (why?) he moved the lever resolutely backward. There was short quantum flicker as the world retro-flowed around him, and went dark. It must be nightime, he thought as he stopped. Oh!! He appeared to be caught in some kind of sticky retaining web again, like a fly on flypaper. The same strange humanoid being, leather-winged and redly glowing, was watching him, and ripped the box from his belt. "Welcome again (whatever that means) Mr. Schroedinger . You remember me, Azrael? You won't be needing this box any more. You see, bishop Ussher was right. The world will be created on October 23, 4004 BC. In the meantime (sic!), there is neither space nor time, so your precious box no longer works. Welcome to eternity, immortal Mr. Schroedinger!". Azrael disappeared, and - slowly - the blackness began to heat up . . .
Monday, June 18, 2007
The Disc of Phaistos Wrapping up the series of Cretan posts today with the one promised on the Disc of Phaistos. Phaistos is on the southern coast of Crete and the Disc was found in the palace at Knossos, near the north coast close by Iraklion. During the middle and late Minoan period the nobles of Crete had a need to communicate discretely (sic!) with one another. The communication was by messenger (runner) - the fastest medium available then - and to ensure secrecy in the case of his capture, the messages were encoded. State of the art encryption in those days was the Skytale ( a form of transposition used in Greece) and the Atbash (a form of substitution as used by the Jews). The messages were written spirally around both sides of a disc, as shown above. The characters used are heiroglyphs whose meaning is unknown to this day, which makes the Disc of Phaistos very interesting to cryptographers as well as historians. The next thing that strikes you is the uniformity of the characters. Indeed, close inspection of the original disc shows us that the signs were made using wooden stamps to stamp the heiroglyphs into the clay! Eat your heart out, William Caxton! Eat your heart out Gutenberg! These Minoans were using movable, reusable type over 3000 years before you! The Disc of Phaistos is the first known document manufactured from reusable stamps. Archeologically it dates to around 1800 BC. But how should the disc be read? From the outside of the spiral inwards? From the inside out? Which side comes first? We don't even know that. The use of stamps would suggest the use of a transposition code, especially if all the stamps were of constant width (not exactly the case here though). And what language is it? Presumably a heiroglyphic (substitution?) representation of one of the contemporary Minoan languages? Timm (2004) looked at the character set and assigned 20 of the 45 unique characters values from Linear A and 16 from Linear B. The following languages have been suggested by archeologists: Ionic, Homeric, Egyptian, Mycenian, Hittite, Semitic, Slavonic and Luwian. In other words, noone has the slightest idea and there is no agreement. Others have tried to interpret ( = guess) what the document is : a game board, an astronomical document, a calender, and logographic writing. Again no-one knows for sure. Wikipaedia has a whole lot more details for you. You can assure yourself eternal fame as a cryptographer if you are able to come up with a unique decipherment, so give it a try ;-) Personally, it was enough for me to go to Crete and actually see it. The missus even bought me a fancy T-shirt with the Disc of Phaistos embroidered in gold and silver on it. There's effable erudition for you, folks, wearing a T-shirt no-one has been able to read for nigh on 4000 years ;-)
Saturday, June 16, 2007
EncoreYesterday will be the day on which John Cramer will re-invent the Time Machine again for the first time . . . I'll tell you about it as soon as it happened ;-) Been there, done that. Am there, doing that. Will be there and will do that.
Thursday, June 14, 2007 : Again;-)
Deja VuIf I remember correctly, tomorrow was the day on which John Cramer invented the Time Machine for the second time . . . And what poor memories do we have that can only see into the past? (Mine no longer even does that properly!). Having just submitted an SF short story about time-travel to an SF/fantasy magazine publisher, I have become acutely aware that the english language does not offer (enough) verbs to cope with time travel. Was - Is - Will be, that's all we have. The assumption being that time progresses linearly (or at least monotonically). We have no verbs for reiterations, none for loops, none for forks (the trousers of time), none for merges, none for parallelism. As authors we have to make the Nth iteration painfully explicit; we need to invent a (new) vocabulary for the situation. Or did I say that already? Or did I say that already? Or did I say that already?
Wednesday, June 13, 2007
Eye yam that eye yam...Liz Hinds' church elders - God bless their narrow Welsh hearts - have been warning her about people she meets online, specifically me, lest they turn out to be mere fictions. Excuse me? This is from people who already believe in at least three fictional beings themselves and who put their trust in all three? Wasn't there something about motes vs. beams? And so, to put their tiny distrustful minds at rest, I'm blogging some personal details - interview style - so that Liz can get to know me better ;-)
Name? Stu
Nickname? Ole Phat Stu
Astrological sign? V (because astrology is nonsense).
Age? 63
Sex? Yes, please! Oh, you meant gender? Male.
Height? 180 cms.
Level of Education? Ph.D., MS, B.Sc.(Hons).
Occupation? Grumpy old pensioner
Birthplace? Edinburgh, Scotland
Marital status? happily married
How many children? None that I know of.
Do you drink alcohol? What else would I do with it? Sure, Beer.
Do you smoke? No.
Favorite outdoor activities? Motorcycling. Walking the dog. Flying.
Favorite indoor activities? Reading. Eating.
Favorite colours? Blues.
Favorite types of music? Blues. And Metal.
Favorite musical groups/performers? Rammstein, Clapton, Hendrix, Baez etc.
Favorite soundtracks? Woodstock.
Favorite song at the moment? "Amerika" (the german version) by Rammstein.
What's in your home CD/Casette player right now?
Mike Oldfield's "Five Miles Out".
What's in you car CD/Cassette player right now?
It's empty. I only listen to traffic (jam) advisories when I drive.
Do you play an instrument? Not any more.
One pillow or two? 2.
Croutons or bacon bits? I like Bacon, preferably Roger.
Favorite salad dressing? 999 islands.
Have you ever had your appendix or tonsils removed? Neither.
Have you ever gone skinny-dipping? Barely ;-)
Do you make fun of people? Yes. Especially pompous ones, incompetents
and politicians (these groups overlap a lot).
As a child, what did you want to be when you grew up?
Engine driver, cosmonaut, Dracula. And mature. Failed on all 4 counts.
What would be your dream job now? Tester/Writer for motorcycle magazines.
Have you ever been arrested for a crime?
"Behaviour likely to cause a breach of Her Majesty's peace".
Places you'd most like to visit? South America.
Mars too, I'd even accept a one way ticket there.
Your first car?
A Bedford van, used for transporting my racing motorcycles.
Dream car? Bugatti Veyron.
Toothpaste? yes.
Shampoo/Conditioner? No ('cos I'm bald).
Favorite season? Summer
Favorite (public)holiday?
Fronleichnam (don't know what it is in English,
it's a religious holiday at the start of june).
Favorite board/card game? Go.
Favorite hobbies? Motorcycling, Blogging.
Favorite sport to play? Archery.
Favorite sport to watch? Motorcycle racing.
Least favorite sport to watch? Golf. Sumo. Chess.
Most humiliating moment? anytime I come second.
Do you have any siblings? One younger sister.
Do you get along with your parents? Yes of course; they're dead.
Favorite place to chill? My garden.
Favorite place to visit? Isle of Man.
What is your bad time of day? Midnight.
What is your good time of day? dawn.
Favorite perfume or cologne? Chanel number 19.
Favorite scent of candle? Bell and book.
Favorite flower/plant? Oaks.
Favorite subject in school? Maths
Least favorite subject in school? Art.
Favorite authors? Terry Pratchett, Larry Niven, Kurt Vonnegut.
Favorite book genre? SF.
Favorite book? Slaughterhouse Five.
Current book I'm reading? Queen Victoria's Bomb.
Favorite magazine? Punch, a now extinct UK humour mag.
Favorite movie you have seen recently? LOTR.
Favorite movie of all time? Being There.
Closely followed by Dr.Strangelove. And by Bladerunner too.
Other favorite movies? 2001 a Space Odyssey, Clockwork, Dark Star.
Favorite actors/actresses? Liz Hurley.
Favorite TV programs? I really don't watch much TV
Favorite cartoon character? Dilbert.
Favorite food? Tapas.
Chocolate or Vanilla? Chocolate
Favorite ice cream? Whipped Bailey's.
Favorite Snapple? Wazzat?
Favorite alcoholic Drink? Stichpimpulibockforcelorum,
closely followed by Guinness.
What is your bedtime? Depends on who's asking ;-)
Best on-line friends? Check the Blogroll
Best friends? Alex, Andreas, Matthias, Marion, Paul, Sylvia,
Chris, Vari, Peter, Moni, Wolfgang, Zora.
Worst enemies? Myself :-(
Good or bad memory? I can remember some things that never happened ;-)
Interesting fact about your childhood? I liked school a LOT.
How many rings before you answer the phone? 3-8.
The first thing you think of in the morning? Upload the blog!
Favorite thing to do when you're home alone? Read, with music playing.
Things that make you feel good? Speed (on a motorcycle, not the drug).
Things you don't like? Incompetence, politicians and corrupt managers.
Worst feeling in the world? Losing a loved one.
Best feeling in the world? Being in love.
Do you get motion sickness? No.
Roller Coasters - Deadly or Exciting? I prefer flying aerobatics.
Thunderstorms - Cool or Scary? Very Cool
Pen or Pencil? Keyboard. And Dragon's dictation software.
Do you like to drive? Yes. But I prefer to ride.
Do you sleep with stuffed animals?
No. But two real live Bulldogs share our bed ;-)
Did you have imaginary friends or a blanket as a child? Jesus.
What is on the walls of your room? Books. Paintings.
What words or phrases do you overuse? "I"
Coolest things anyone ever gave you? Thrush :-(
How would you characterize your political leanings? Peacenik socialist.
If you could pick one super-human power, what would you choose?
Perfect kindness. Impossible? OK then, perfect memory.
Favorite Quotes/Lyrics/Poems:
Quote? "I know you all and will awhile uphold the unyoked humour
of your idleness" Shakespeare.
Lyrics? "Amerika" by Rammstein.
Poem? "This be the verse" by Philip Larkin.
Bible Verse? Galatians 4:16 ;-)
Can you keep secrets? 11497989095545517501 of them ;-)
What would your Famous Last Words be?
Da Capo! (Sorry, Liz, that's a recycled Buddhist joke ;-)
Monday, June 11, 2007
Wrong, wrong, wrongJust been thinking about all the stuff they taught us at primary school which turned out to be just plain wrong. What were you taught wrongly? Here are nine of mine :-
So what were you taught wrongly? Blog your answers or mail me.
Thursday, June 7, 2007
Hiking Cretan Canyons : the Imbros Gorge. Crete not only has some great beaches, it also provides for some interesting hiking through spectacular gorges (=canyons). Hikes which are short (5 miles) but steep ( over 1000 feet drop) and which thread you along the riverbeds of the canyons (at least in the dry season ;-) . I'll show you the Imbros Gorge today. Entering the Gorge at the top, where we paid an upkeep fee (national trust) of a couple of Euros, you start off down the airily wooded canyon along a well-defined narrow path under scrubby trees. Soon the going gets steeper (be sure to wear some solid walking shoes, not tennis plimsolls you brought for the beach) and huge rocks loom over the track, rocks so large that they even have trees growing out of them. Beware of the occasional small rockfall, easily heard coming down. Beware too of the stench of the Rod of Hercules plants which you smell scores of yards in advance if the wind is coming up the canyon ;-) Later the canyon narrows with steep walls. Look carefully at that last photo. About 20 feet up on the right canyon wall above the wife you will see a small red cross denoting the high water mark in a recent rainy season. You certainly need to check the weather reports in advance to avoid being caught in a flash flood! We also encountered some wild goats coming up the canyon. They retreated to a point where they could climb (nay, run) up the canyon walls until we had passed by below :-). If you get footweary in the broiling sun, you can always get some ass to help you manage the rest ;-) There is a checkpoint about ½ way through, where the gorge opens out and the terrain flattens somewhat. This serves as the ticket office for those coming up from the bottom. So if you've walked half the way up and then find you have no cash with you, tough shit, man! There is another longer canyon about ten miles west. It is a longer (11 miles) but much easier walk. And so busloads of tourists get deposited at the top, walk down, and get picked up by a boat at the bottom and taken to board their bus again where the road meets the coast. So it gets overcrowded, whereas we had the Imbros gorge almost to ourselves, perhaps meeting a dozen people coming up the canyon. Aforesaid boat, being a monopoly, charges a €8 fee for the transport. PS: Today's blogpost is dedicated to fellow-blogger Alan Sloman, who is hiking from Land's End to John'o'Groats, and already has 80% of his trip behind him. Through his blogging we can share an inkling(sic!) of what his trip is like :-) Go, Alan, Go!
Tuesday, June 5, 2007
Paris Hilton goes down . . .But we knew that anyway ;-) More relevant is that she has gone down for at least 23 days and hopefully all 45. So we might get 3 to 6 weeks of peace and quiet from the gutter press. But the paparazzi will be there in 23 days time, like vultures at a corpse. Meanwhile, the yellow press is not lacking for scandalous stories. It just turned out that the Pastor Pastoris - Don Paolo Curtaz - is the father of a bouncing three-year old daughter. The Pastor Pastoris just FYI is the head of the Roman Catholic church when the Pope is on holiday ;-) The One True Church™ has excelled itself again ;-) Appropriately, Curtaz is the vicar of a high mountain parish near the top of the Aosta valley called Gran Paradiso; this is obviously a case of 'nearer my God to thee' ;-) Curiosity thus drove me to reread the Codex Canonicus. There I read that the fathers (sic!) of the OTC™ are allowed to f*ck you, just not to marry you. The One True Church™ takes responsibility for the cost of child support for the bastards. However, here it is only for the first three bastards (limited liability clause). What a cock-up! PS : Nowhere on Curtaz website could I find any word of this, so I rely on La Stampa ;-)
Sunday, June 3, 2007
"All Cretans are Liars"C ontinuing the blogging episodes that I started last month about our vacation on Crete, I thought I'd give you some ancient Cretan logic questions to puzzle you. You may have heard some of them already, after all they're from 600 BC. "All Cretans are Liars" is a logical paradox created by Epimenides (in ca. 600 BC), who was himself a Cretan. So - by his very own claim - Epimenides must have been lying. In which case he must have been telling the truth. But if this is true, then he must have been lying. This contradiction has become known as Epimenides' Paradox. In the subsequent years this paradox has been used to teach logic to schoolchildren, all of whom delight in such logical puzzles as follow here:- G iven that "All Cretans are Liars" and "All Greeks are Truers (truthtellers)", think about this puzzle : At a fork in the road you meet two people, one of whom is a Cretan and the other a Greek, but you don't know which is which. One of the roads takes you to (say) Heraklion and the other to Xania. You want to go to Xania (to try the cocktail I mentioned at the end of May ?) but may ask ONE of the people at the fork just ONE question. How do you phrase that question to be 100% sure of choosing the right road to Xenia? Stop reading now and try to answer the puzzle before I tell you how to solve it. Y our question should be "If I asked the other person which road goes to Xenia, which road would he tell me?" Assume you talked to the Cretan. Then the other person was the truth-telling Greek and would have pointed down the road to Xenai (Road X). So the Cretan would lie and point you down road H (to Heraklion). Had you talked to the Greek, then the other person was the lying Cretan. He would have pointed down the road to Heraklion (Road H). And so the Greek truthfully tells you that. In BOTH cases the answer is Road H. And so you should always take the other road (X) which takes you to Xania. N ow let's make it a little harder. At the fork in the road is just ONE person, either a Cretan or a Greek, but you don't know which. You may ask this person again just ONE question. How do you phrase that question to be 100% sure of choosing the right road to Xenia? You may not refer to any third party! Stop reading now and try to answer the puzzle before I tell you how to solve it. Y our question should be "If I had asked you just a short while ago which road goes to Xenia, which road would you have told me?" Assume you talked to a Cretan. Then the first time he would have lied and pointed you down road H. He knows this too, and so lies about it and points you down road X. Assume you talked to a Greek. He would have pointed down road X and tells you truthfully that he would have done so. In BOTH cases the answerer points you down road X to Xenia :) Finally, the really difficult puzzle, to which I expect only Four Dinners (or someone who thinks like him) could provide a correct answer. Y'all mail me your answers now :-) At the fork in the road is just ONE person, either a Cretan or a Greek, but you don't know which. You may NOT even ask this person EVEN ONE question. So what do you say to be sure of choosing the road to Xenia? Stop reading now and try to answer the puzzle, then mail me your solution(s) for due blog-credit later in the week :-) So, if you managed to answer all these puzzles without my help, you are now qualified to go read Douglas Hofstadter's Opus Gödel, Escher, Bach (ISBN 0465026567). Enjoy! |
 Comments Policy Gallery (12 photos) Impressum Maths trivia Recent readership Search & Sitemap Skyline Meme Links  RSS Feed Dr. Stuart Savory, who is an overeducated, grumpy multilingual ex-pat Scot, blatently opinionated, old (1944-vintage), amateur cryptologist, computer consultant, flying instructor, bulldog-lover, Beetle-driver, textbook-writer, long-distance biker, blogger and webmaster living in the foothills south of the northern German plains. Not too shy to reveal his true name or even whereabouts, he blogs his opinions, and humour and rants irregularly. Stubbornly he clings to his beliefs, e.g. that he's not really evil, or even anti-american, in spite of Dubya's efforts to convince him that he should be. Oh, and he really has fun with his English Bulldog bitch.
And her new son 'Kosmo', born April 2nd, 2007. The other 5 pups have found nice homes too, all gone.
Link Disclaimer ENGLISH : I am not responsible for the contents or form of any external page to which this website links. I specifically do not adopt their content, nor do I make it mine. DEUTSCH : Für alle Seiten, die auf diese Website verlinkt sind, möchte ich betonen, daß ich keinerlei Einfluß auf deren Gestaltung und Inhalte habe. Deshalb distanziere ich mich ausdrücklich von allen Inhalten aller gelinkten Seiten und mache mich ihre Inhalt nicht zu eigen.
Content Disclaimer
Archive 2006:
Archive 2005:
Archive 2004:
Archive 2003:
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This blog is not (even politically) correct. It consists of 72% satire & sarcasm,
31% scientific reporting, and at least 4% arithmetical errors ;-) Thus everything blogged
here should be taken with a pinch or 3 of NaCl.
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