I did a 5 day round-trip trek through the Colombian jungle to Ciudad Perdida – the lost city.  It was an amazing experience.

It’s a lot harder than the Inca Trail.  There are several river crossings, where you have to wade across the river.  The month before I visited, a French tourist was swept away and drowned at one of the crossings.

On the return trip the water level had risen, so at one of the crossings we used a flying fox.

There are wooden shelter camp sites spaced along the trail, complete with bunk beds, hammocks and toilets.

The hiking can be exhausting and if it rains there are parts of the trail that can be difficult to navigate.

Indigenous tribes still live in the area.

There aren’t any large animals in the jungle, but there are lots of frogs, butterflies, mosquitos, some snakes and we even encountered a scorpion in one of the camp sites.

The Lost City itself was built around 800 AD and was where the high chief of the tribes ruled from.

The city was abandoned around the time of the Spanish conquest.  There isn’t much left of the city, except some stone walls.  Although the city’s existence was known to the local tribes, it was only in 1972 that it became known to the outside world.  A group of treasure hunters discovered the site and dubbed it the Green Hell.

In 2003, the rebel group ELN kidnapped 13 foreign tourists.  Five were soon released because they weren’t fit enough or weren’t wearing suitable shoes for the rebels’ planned march.  One hostage escaped the next day, but the remaining seven were held for over 3 months before finally being released.  After that the government acted to curb the influence of the paramilitary groups in the region and permanently stationed a group of soldiers at the site of the ruins.

My review of Analog’s July/August issue is now up at The Portal.

http://sffportal.net/2011/08/analog-julyaugust-2011/

I’m fascinated by the way loopholes and unforeseen problems arise in the design of systems.
When I was at a university, I worked one day a week at a computer games company testing games. Even though computer and board games generally cover relatively simple systems, they can still fall afoul of complications.  What happens if I use my Ring of Wishes to cast Raise Dead on a zombie that’s just been murdered by a half-vampire wielding a Sword of Utter Slaying?

Languages are another set of rules with innumerable exceptions and contradictions.  The assignment of gender for nouns can seem somewhat arbitrary in some European languages.  For example, cola is usually feminine in German (die Cola), but in Austria, Switzerland and parts of southern Germany, it’s neuter (das Cola).  Japanese has two different verbs meaning “to be”, one for inanimate objects and one for animate objects.  If talking about people or animals you use the verb iru.  If talking about things you use the verb aru.  I took some delight in asking my Japanese teacher about possible grey areas such as ghosts, vampires, dead bodies and robots.

These border areas and loopholes aren’t always trivial.  Michael Lewis’ The Big Short and Matt Taibbi’s Griftopia detail some of the loopholes investment bankers used to gamble billions of dollars and help bring about the global financial crisis.

Kurt Gödel’s Incompleteness Theorem is regarded as one of the most important mathematical proofs of the 20th century.  It involves a lot of complicated maths, but the basic idea is that it shows it is impossible to construct an internally self-consistent rules-based system that is able to cope with a statement along the following lines:

This sentence is not provable.

This is related to the Liar Paradox (“This sentence is false”) that Doctor Who and Captain Kirk have used to befuddle unfortunate computer opponents.

The Incompleteness Theorem applies to logical systems, not religions.  Some religious apologists have gone so far to argue that the theorem proves that reason alone is not sufficient and faith is required to understand the universe.  Jewish scholars have tried to construct a logical system of what is and isn’t permissible on the Sabbath.

Observant Jews can’t go ten-pin-bowling on the Sabbath.

It’s hard to find a more amusing system of torturous logic and elaborate handwaving than the one that has resulted from trying to adapt 2000-year-old beliefs supposedly dictated by a god that couldn’t anticipate the advent of electricity.

When I was in Jerusalem, I witnessed firsthand some of the effects of the Sabbath.  Parts of Jerusalem on a Friday afternoon feel like being in a horror movie.  Traffic stops running.  Storekeepers pull down the shutters on shops.  Strange bearded men chant arcane phrases from ancient tomes.  Wizened crones threateningly whisper that if you know what’s good for you, you’ll be gone before sunset.

The basic idea of Sabbath is to have a day of rest and spend time with your family.  That sounds like a pretty good idea.  However, it’s not all joy and happiness.  People not observing this commandment are supposed to be stoned to death. (Numbers 15)  Fortunately, this doesn’t happen very often these days, but a couple of years ago, some ultra-Orthodox Jews threw rocks at the car of the mayor of Jerusalem after he allowed a car park to open on a Saturday.

Sabbath begins just before sunset on Friday and ends when certain stars become visible on Saturday night.  Since the writers of the Jewish bible thought the earth was flat, they didn’t take into account places where at times there are no sunsets.

Jewish Law in the Polar Regions
http://en.wikipedia.org/wiki/Jewish_law_in_the_polar_regions

Similar problems confront the Islamic observance of Ramadan.  When a Muslim was due to visit the International Space Station, the Islamic National Fatwa Council created a guidebook called “Guidelines for Performing Islamic Rites (Ibadah) at the International Space Station” covering issues such as “how to pray in a low-gravity environment, how to locate Mecca from the ISS, how to determine prayer times, and issues surrounding fasting.”

Originally there were 39 things prohibited from being performed on the Sabbath.  These were variously interpreted and added to over the years.  The original rule forbidding cutting was extended to include not climbing a tree – because if you broke a twig that would be a form of cutting.
The rule that has caused the most headaches for people trying to live in the modern world is the rule forbidding the lighting of a fire.  Most rabbis agreed that electricity was a form of fire and so observant Jews aren’t supposed to turn on electrical items on the Sabbath.  Opening a refrigerator door is usually permitted (as the fridge is already on), but only if the light inside the fridge that comes on automatically has been disabled.

Why do orthodox Jews refrain from riding bikes on the Sabbath?
http://judaism.about.com/od/sabbathdayshabba1/f/sim_shabbike.htm

All kinds of workarounds exist to circumvent these laws, with varying levels of approval from different religious authorities.  There are timers which turn lights on and off and modified elevators that automatically stop at every floor on the Sabbath.  In 2001, the Israeli parliament passed a law “ordering the planning and building of all residential buildings, and public buildings which have more than one elevator, to install a control mechanism for Shabbat in one of the elevators.”

In Jerusalem, visiting the Western Wall is an important activity on Sabbath, but the modern world requires the use of electrical-powered items such as metal detectors.

God Bless those Chief Rabbis.

These rules can be abandoned if it is a life-threatening situation, but even then what constitutes a life-threatening situation is open to interpretation.  Traditionally breaking the Sabbath was only applicable if Jewish lives were at risk.  One of the most famous Rabbinical scholars, Maimonides, wrote that: “as for gentiles [non-Jews], the basic Talmudic principle is that their lives must not be saved, although it is also forbidden to murder them outright.”

Of course, this is not the widely prevailing view today.  In 2010 a Jewish search & rescue team commander in Haiti spoke of “proudly desecrating Shabbat” to help rescue non-Jewish earthquake victims.

Another rule that has caused frictions in some neighbourhoods is that observant Jews are prohibited from carrying anything outside their home on the Sabbath – which can make visiting a synagogue difficult.  To get around this, “eruvs” are used – boundaries marked by things like electricity poles that specially designate the entire area as “home”.  For example, the Melbourne Eruv covers large areas of St. Kilda and Caulfield.  The Council of Orthodox Synagogues of Victoria also provides an eruv hotline.
http://www.cosv.org.au/gsqp.php?gsqp=eruv
(Road works have at times interfered with the sanctity of the eruv).

Another well-known Jewish system of beliefs is the set of rules governing which types of food can be eaten.  The kosher system prohibits certain types of meat and doesn’t allow the mixing of meat and dairy. (I cant haz cheeseburger!)

Which basically amounts to making life difficult for yourself.   After the introduction of Coca-Cola, a rabbi asked to check the ingredients to ensure they were kosher.  The formula for Coca-Cola was a secret, but one rabbi was given the ingredients and sworn to secrecy.  Rabbi Geffen later wrote:

“Because Coca-Cola has already been accepted by the general public in this country and Canada and because it has become an insurmountable problem to induce the great majority of Jews to refrain from partaking of this drink, I have tried earnestly to find a method of permitting its usage. With the help of G-d I have been able to uncover a pragmatic solution in which there would be no question nor any doubt concerning the ingredients of Coca-Cola.”

It is possible to have fun with this system though.  For example The Kosher Guide to Imaginary Creatures informs readers as to whether creatures such as bigfoot could be considered kosher.

After Jordan, I spent a week in Israel.
Jerusalem is a fascinating city crammed full of too much history for its own good.
You might think you have problems with your neighbours, but at least your disputes don’t have a 2000-year-old history.

The Dome of the Rock.

The Western Wall is a place where people use various methods to try and talk to god.

Looking for a message from above.

I visited Bethlehem in the Palestinian Territory.  There is a big “peace” wall dividing the Palestinian Territory from the rest of Israel.  It is decorated with graffiti, peace slogans, as well as advertising for nearby restaurants.

The end times are prophesised when the Antichrist arrives in the Holy Land. I encountered not one, but two devils on the streets of Jerusalem.

The Devil took time out to get a tattoo.

And what rough beast, its hour come round at last,
Rolls towards Bethlehem to be born?

I visited Masada, the Jewish mountain fortress where rather than surrender to the Romans, a group of almost 1000 Jews killed themselves.  Personally I think they made a bad choice.  Let yourself be killed by a bunch of zealots (in the original sense of the word) or join up with the empire famed for its pizza, orgies and The Sopranos.

I stopped by the Dead Sea for a float.

I had a look in the Shrine of the Book, which houses the Dead Sea Scrolls.

I also visited Acre, last of the Crusader cities to fall.