5 PM

Tick tock...tick tock...Have you ever thought what happens at 5 PM everyday?

If you were in space, listening to the earth with a giant stethoscope, you could hear approximately one third of the men and women who are in the same time zone, push back their chairs as they finish work for the day.The discerning diaphragm might also pick up the familiar sound of MS Windows shutting down, the keys turning in their mortice as the doors are locked for the final time.

The spying eye high in space would suddenly see an entire longitude plunge into darkness as the office lights are turned off. The stethoscope would pick up the cheery babble of people as they said goodbyes for the day, relieved to be going back to their home and hearth.

And then...silence. The profound silence of deserted buildings and empty carparks.

Why does it have to be 5 PM? Well, because 5 PM comes between 4 PM and 6 PM.The civilized society views the world in thirds. This third is mine, the other third is yours. A pack of bread has twelve loaves, to be had in fours. People like to have a beginning, a middle, and an end.

No surprise then, that the day has 24 hours, divided into three equal eights. Eight for sleeping, eight for working, eight for fun.If 5 PM was 4 PM, you would have to start at 8 AM. Too early. Too dark in many parts of the world.

Finish at 6, and you have the mortification of getting home at seven. There's a kind of watershed feeling about seven. It's the peak hour. TV channels start their best shows at 7, Classic FM put in the connoisseur's hour, Channel 4 start the news and the latest feed about Big Brother...you don't want to be getting home at seven. It's got a kinda... missed the boat sort of feeling. Therefore it has to be 5.

Or does it?

I always view 5'o clock with some satisfaction, but for somewhat different reasons. For me, it's the start of the grace hour, the unpaid hour I put in when I can, freed from the burden of having to work for a living, having to fulfil my obligation to my employers. It's got the refreshing whiff of going the extra mile, of claiming the high moral ground, of the satisfaction of making my colleagues feel slightly guilty as they slam their doors on their way home.

Five PM is a familiar hour on Saturdays. As you tune the radio in to Five Live, you hear that same unmistakable voice reading out the football scores as it has done for the last 20 years...Manchester City 1, Aston Villa nil....Bolton nil, Charlton nil...Hibernian 1, Dundee 1....As if anybody cares about Hibernian and Dundee. Really!

But you can see where he is coming from, can't you? It's 5 PM and he has to live the tradition. There will be crushingly boring accounts of the five-nations rugby coming up, with lurid descriptions of how France mauled Italy in their backyard, but you don't switch off. You can't.

It's 5 PM. And it's Saturday. Switching off takes a break.

Occam's Razor- Applications and Failures

William of Oakham, mispronounced as Occam, used to live not far from where I now stay....but around 700 years ago. His lasting legacy to philosophy, and indeed to problem solving, was the principle called "Occam's Razor", which essentially states that in trying to resolve to a problem, try and reach for the simplest solution that explains all parts of the problem.

Occam's razor implies that in reaching a solution, try and make as few assumptions as possible. I have outlined this in bold, as this is the key to interpreting Occam's razor. This is also called the "Principle of Parsimony".

Occam's razor is a very good way of resolving debates in practically any area, and I'll use it to try and sort out some burning issues (see www.indiancricketfans.com).

But before that, here are some examples where Occam's razor has been applied.

In 1976, when Viking 1 was orbiting Mars, it took this picture, which looked like a human face. (1)

Some people, among them scientists, thought that this was evidence for the presence of life on Mars. However, in doing so, they made the following implicit assumptions:

1. There was intelligent life on Mars.

2. Martians knew what humans look like, or they looked like humans themselves.

3. Martians wanted to send a message to earthlings.

4. Martian civilization would have been present for several thousand years without scientists on earth detecting evidence of the same, despite strenuous efforts.

Now, that's a lot of assumptions. Astronomers working on Viking 1 had a simpler explanation: that the face was created by shadows. This was confirmed when the Mars Global Surveyor took photos of the same region of Mars on three separate occasions in 1998, 2000 and 2001, when the sun was striking Mars at different angles, and no facial features were seen, as demonstrated in the photograph below.

Occam's razor would have exhorted us not to make unnecessary assumptions, and go for the simplest explanation that would explain the findings, which is exactly what the astronomers did.

In the 1970s, the world woke up to these wonderfully symmetrical crop circles in some parts of England (2).

Many took it as imprints left by flying saucers, and interpreted it as evidence of life without Earth. Occam's razor would have told us that given the lack of evidence of UFOs and the complexities involved in getting these objects to arrive from distant galaxies to earth, the far simpler solution would obviously be that these were man-made phenomena. This was later proven right, as, some twenty years later, two people admitted to have made the original crop circles.

Medicine makes use of Occam's razor.An unkempt man known for drug & alcohol abuse, presents to you, vomiting blood. You do some tests and find that he is jaundiced, that he is anaemic, and that his platelet count is low. Before you have taken a proper history, you might be tempted to assume that his jaundice is because of viral hepatitis picked up from drug abuse, that he might have taken some aspirin to relieve his liver pain, and that this may have caused bleeding from his gut, while lowering his platelet count.

The simple explanation for all the features is of course that the man is an alcoholic. That would explain his jaundice, the bleeding from the gut from dilated veins in the gullet and stomach, and the low platelets caused by destruction from an enlarged spleen. Occam's razor has stopped you from invoking two disparate causes, hepatitis and asprin for his symptoms, when merely one, alcohol would have sufficed.

So does Occam's philosophy always involve going for the simplest solution? No. Remember, you have to go for the simplest solution that explains the problem in its entirety.

To illustrate, in the following problem, the task is to draw one line that separates blue squares from the red dots (3).

There are three approaches, lines A, B and C. Which is correct?

Now going by the inherent need for a simple solution through Occam's razor, one might be tempted to go for line A or B in preference to line C. But clearly, line A is a very rough solution, and line B, although much better, does not separate all the blue squares and red dots from each other. Therefore, although the squiggly C seems a rather complicated solution, that is the one we must choose, as it solves the problem in its entirety.

Can we use Occam's razor to resolve some of the debates that rage on forums the world over? Possibly. (see http://www.indiancricketfans.com/)

It has been suggested that 9/11 was in fact a conspiracy by the US government itself. There are several assumptions in this line of thinking. First, you have to assume that planes that flew into the towers were flown not by Arabs sympathetic to Al-Queda, but by US agents, who agreed to give up their own lives and risk the lives of thousands of others on government orders. Doesn't gel, because the ideology of suicide missions is practiced by the followers of Al Queda far more than US agents.

The second assumption is that, using the planes as a mere decoy, the government engineered massive blasts in the twin towers.

The third assumption was that the government did all this as a devious means of turning world and domestic opinion against Al-Qaeda, and thereby paving the way for the Iraq invasion.

Occam's razor asks you to look for the simple explanation. That the towers were in fact brought down by the planes. This was later supported by reliable reports of how some of the apparently ordinary Arab passengers on the plane had undergone training in flying and combat shortly before the episode.

The second debate was about whether, if Muslims in Europe had their way, Sharia law would prevail. We looked back into history and enquired if Mughal or Muslim rulers who ruled 600-1000 years ago had imposed Islamic law.

The inherent assumption in this was that Muslims of today would behave in a similar fashion to those rulers of a 1000 years ago. There is no evidence for this. Certainly, Christians of today do not launch Crusades, like their predecessors in the middle ages.

A far simpler solution, and William of Oakham would have approved of this, would be to look at what Muslim governments of today are doing in the parts of the world where they rule. With one exception, Islamic law prevails, and therefore it is fair to say that had Muslims controlled Europe, they would have imposed Sharia law on the indigenous population.

In another debate, this time on cricket, the Pakistani fans, the PCB and Asif and Shoaib have themselves vehemently protested their innocence in the doping case. The conditions that would have to have been present in order for them to be innocent would be:

1. The supplements they took were contaminated with nandrolone

2. The contamination was sufficient to account for the levels in the body

3. They did not know about the contamination

4. None of their teammates took the supplements

5. The nandrolone hung around in their body for months, despite being taken orally, thus causing them to pull out of all subsequent occasions when they could have been tested, such as the World Cup.(Unlikely. Oral nandrolone has a half life of days, and would disappear very quickly from the body, unlike the injected steroid, which persists for months)

Occam's razor would suggest that they were guilty as charged, and that there were just too many coincidences (assumptions) to make it a plausible story. (Note that this is not necessarily my personal opinion)

The next time you are in a debate or are grappling with a difficult problem, remember the principle of parsimony. It just might help you.

Failures Of Occam's Razor

Lest people use this blindly, let me quote something I read, "Occam's razor is no substitute for insight, logic and the scientific method". In the words of Einstein, "Everything should be made as simple as possible, but not simpler."

Indeed, much of science draws on Occan's razor, and mostly it stands up to scrutiny. There are occasions though, when it lets you down badly, and one must always be aware of such pitfalls.

Let me give you three examples, one from medicine, one from genetics, and one from nature to illustrate this better.

Until very recently, upto six years ago, hormone replacement therapy (HRT) was considered the panacea for women who had recently reached menopause. It made intuitive sense- it made them look younger, it stopped their hot flushes, it strengthened their bones, and above all, the oestregen component lowered the levels of cholesterol in the blood, thus holding out the promise of reducing heart attacks and strokes in the future. Quite clearly, Occam's razor pointed to a win-win situation for HRT. Why would anybody be worried about using it?

Imagine the shock of the medical community therefore, when, a few years ago, a very large controlled study, called the Women's Health Initiative, showed that HRT in fact increased the risk of heart attacks and strokes in post-menopausal women significantly.The finding led to a worldwide drop in prescriptions for HRT. It is now only used in the short term for alleviating troublesome symptoms such as hot flushes.

Another example.

High alcohol intake has been shown to be a risk factor for head and neck cancer in observational studies. This is thought to be due to acetaldehyde, a carcinogen that is obtained during oxidation of alcohol in the body. There are two allelles for the gene that oxidizes alcohol- one, let's call it B2, converts alcohol to acetaldehyde 100 times faster than the other, say B1. Scientists therefore justifiably postulated that persons who had two copies of B2, would be at a far higher risk of head and neck cancer than those with B1-B1 or B1-B2.

In reality though, it turned out that both B1-B2 and B1-B1 had a far higher risk of developing cancer than B2-B2. The reason for this was that acetaldehyde has very unpleasant effects on the body- it makes people feel unwell. The homozygotes for B2-B2 therefore cut down on their alcohol consumption to escape the dysphoric effects of acetaldehyde, while those with genotypes B1-B2 or B1-B1 continued to drink with impunity, and thus became more susceptible to head and neck cancer.

The principle of parsimony would have suggested a higher risk for B2-B2 based on the genotype, but it obviously could not account for confounding by alcohol consumption.

Finally, let me give you a topical example from nature. If you watch National Geographic, you will know that there is a huge concern about the dwindling number of cheetahs. There are only 10,000 of them left in the wild, they do not mate very easily, and the cubs they produce are often killed by other predators. Scientists were concerned whether, firstly cheetah females had enough males to mate with, and secondly even if there were enough males, whether mating was taking place often enough, a view based on Occam's razor, due to the low density of cheetahs in general, and the behaviour of females studied on camera.

Imagine the surprise of nature scientists therefore, when DNA analysis of cheetah cubs recently revealed that female cheetahs were in fact shamelessly polyandrous, with up to half of their litter being sired by different males. That is to say, they were sleeping with every stranger that came along!

It is thought that this kind of behaviour offers a survival advantage by allowing genetically variable offsprings to adapt better to vicissitudes and by reducing infanticide by male cheetahs, who are often confused as to the parentage of the cubs!

Who would have thought, eh?

References:
1. http://www.mira.org/fts0/intro/occam.htm
2. http://www.ufomystic.com/wp-content/uploads/crop_circles1.jpg
3.http://users.openface.ca/~cobe/occams-razor/