In the movie Contact Jodie Foster and Matthew McConaughey are at a cocktail party in Washington debating the possible existence of God. Jodie is not a believer. She is a scientist who wants empirical evidence before believing anything. He is an intensely religious believer who feels that faith, by definition, is belief in God without empirical evidence.

Jodie Foster: “It’s like you’re saying that science kills God. What if science reveals that he never existed?” Matthew McConaughey walks her out into the yard. Jodie says, “I have one for you. Have you ever heard of Occam’s Razor? It’s a scientific principle. She says that all things being equal, the simplest solution tends to be the correct one. Which one is more likely? That an almighty guy created the universe and decided not to give any proof of its existence, Or did it just not exist at all and did we create it so that we wouldn’t have to feel so small and alone?

Matthew McConaughey: “I could not imagine a world where God did not exist. He would not.”

Jodie Foster: “How do you know you’re not kidding yourself? For me, I would need proof.”

What is Occams Razor about? Occam is a small town in the county of Surrey, England, about 15 miles from where I was born and not far from the M25 ring road that surrounds London. These days you spell Ockham. It probably would have faded into intellectual oblivion centuries ago if it weren’t for a guy named John who lived in Occam and thought of himself as a bit of a philosopher. This was in the 14th century, so long ago that people didn’t even have last names. Juan was known as Juan de Occam. He first posited the theory that Jodie Foster – Occam’s Razor. Oddly enough, he never stated what we now call the scientific principle that bears his name, which says that, all things being equal, the simplest solution tends to be the correct one.

What he did say (in Latin, which was the language of 14th century English intellectuals) were two principles:

The principle of plurality: plurality should not be postulated unnecessarily.In simpler language, that means don’t make it more complicated than it needs to be.

The principle of parsimony – It does not make sense to do with more what is done with less.If you can solve a problem with a simple solution, what is the point of looking for a more complicated solution?

It was future generations of philosophers who promoted the theory of simplicity on his behalf, no doubt backed by the knowledge that John was a Franciscan monk who took his vow of poverty seriously. He lived a very simple life.

Occam’s razor (the razor part refers to the process of debugging more complicated explanations to get to the truth) is not a problem-solving tool. It doesn’t prove anything. It is a heuristic motto, a way of suggesting solutions.

Let’s say someone presents you with a light bulb that turns on without being screwed in. It looks like a normal light bulb, but it lights up without being attached to anything. How is it possible? Think about it for a moment and you might come up with three possible solutions:

1. They have invented a way to transport electricity through the air as a radio wave.
2. They have found a way to hide the power cord so you can’t see it.
3. They have hidden a battery inside the stem of the bulb.

I have listed those three explanations, from the most complicated to the simplest. Occam’s Razor suggests to you that the number three is the simplest answer, and therefore the most likely.

Let’s look at a more complicated problem, the sudden appearance of crop circles in farmers’ wheat fields. In 1991 circles began to appear in fields near Southampton, England. It didn’t attract much attention. Another more complicated pattern soon appeared in the Matterly Bowl, a natural phenomenon that is visible from several major roads. This generated a lot of publicity and public opinion about the cause of the phenomenon went crazy. Suddenly, crop circles appeared all over the place. The designs became more and more complicated.

The conspiracy theorists had a field day and had half of England convinced that aliens from outer space were landing at night to send us messages. A simple application of Occam’s razor would have solved the problem. The idea that aliens were responsible was the most complicated solution. The simplest solution was that humans did it as a joke.

Meanwhile, Doug Bower (the secret author of the circles) had a marital problem. His wife thought he was having an affair because he often disappeared overnight. She tracked the mileage on her car to determine that she was driving long distances. (In England, 50 miles is considered a long journey. It can never be more than 72 miles from the sea, which would be the distance from Coton in Elms, Derbyshire to the North Sea, according to the government ordinance survey). his wife more than the anger of the farmers whose fields he was damaging, confessed that he and a friend of his had caused the circles.

If you are a fan of the TV series House, you will remember that the third episode of the first season was called Occam’s Razor. The residency students in their infectious disease ward at a New Jersey hospital are convinced that their patient has a previously unknown exotic disease. House maintains that the answer is simpler, that someone screwed up his treatment.

Why does Occam’s rule work? Why is the simplest solution the most likely? Good question. I do not know why. That’s why apples fall from trees and hit philosophers, I guess. It is just one of the laws of our universe. Remember that John of Ockham lived in a very simple world. He was not concerned about the tsunamis in Malaysia or the miners trapped in Chile.

We live in a very complicated world that is difficult for us to understand. That alone makes Occam’s razor a more valuable tool than it was in John’s day. Remember that, when your IT expert is going through a large amount of paperwork explaining why horse food sales are down. Maybe it’s just because horses don’t like the taste of it. If you still say “Yes, but I need to understand why Occam’s rule works,” I suggest you reread Occam’s rule.

While the odd name Occam’s Razor may not be a troubleshooting tool, it will serve you as a very useful troubleshooting or heuristic device. When faced with trying to understand a problem, consider that the simplest solutions are the most likely.