Saturday, May 22, 2010

KISS Principle and Occam's Razor


The KISS Principle and Occam’s Razor (also written as Ockham's Razor)


The Kiss Principle refers to the acronym for Keep It Simple, Stupid or the more polite version, Keep It Short and Simple.

There are various explanations as to what the principle actually means, but all have the key message that simplicity should be the goal and that unnecessary complexity should be avoided.

Others have formulated similar concepts and expressed similar ideas in the past:

Albert Einstein: “Everything should be made as simple as possible but no simpler.”

Leonardo Da Vinci: “Simplicity is the ultimate sophistication.”

Antoine de Saint Exupery: "It seems that perfection is reached not when there is nothing left to add, but when there is nothing left to take away".

There is a similar, but not equivalent, principle to Kiss known as Occam’s Razor, which is usually summarised as “The simplest explanation is usually the best one.” In medical circles this is sometimes expressed as “If you hear hoofbeats, think horses, not zebras.”

Just as there are a number of formulations of the Kiss Principle, so there have likewise been numerous formulations and reformulations of Occam’s Razor, including the following:

"If you have two theories that both explain the observed facts, then you should use the simplest until more evidence comes along"

"The simplest explanation for some phenomenon is more likely to be accurate than more complicated explanations."

"If you have two equally likely solutions to a problem, choose the simplest."

"The explanation requiring the fewest assumptions is most likely to be correct."

That is not to say that complexity should always be avoided as an explanation. The more complex explanation may actually be the correct one. However, where both a complex solution and a simple solution are possible and reasonable, the simpler one will usually be the correct one.

Although there is an overlap between the Kiss Principle and Occam’s Razor, they are not the same. The Kiss Principle says to aim for simplicity and avoid complexity; Occam’s Razor says that the simplest explanation is usually the correct one.

Examples where Kiss not used:

It is easier to show examples where the Kiss Principle has not been applied.

One example of the opposite of the Kiss Principle are the cartoons of Rube Goldberg (such as the one above). A Rube Goldberg machine is one which performs a very simple task in an over-engineered, complex fashion, usually by a chain of motion events. The car advertisement that shows things falling etc is an example. There are also numerous example on YouTube of people who have deliberately built Rube Godlberg machines.

Other examples contrary to Kiss are:

-    "instruction creep”, where instructions increase in number and size over time until they are unmanageable;

-    “function creep” where an item, process, or procedure designed for a specific purpose ends up serving another purpose for which it was never planned to perform;

-    “scope creep”, where a project’s scope is increased so that more tasks must be completed, without an increase in budget or time; and

-    “creeping featurism”, where systems become more complex over time as more and more features are added to the original device, plan etc.

(So who works the VCR, DVD etc at your house? And how many functions do you actually use on your mobile phone?)

Practical applications:

Some practical applications of the Kiss Principle:

-    Break tasks into smaller tasks and deal with them as smaller ones.

-     Likewise break problems down into smaller problems and address the smaller ones.

A related aspect:

I once saw the Great Randi interviewed. Randi is a professional magician who is renowned for debunking paranormal claims and pseudoscience and who came to prominence for exposing spoonbender Uri Geller. He is also a founder of various skeptic associations.

In the interview I saw, Randi stated as a principle that where two explanations are possible for something, one explanation is consistent with known laws and principles of the universe and the other requires you to suspend belief in those laws and principles, then the former should prevail until the other is proven. Thus when a child awakes and finds presents at the foot of his bed on Christmas Day morning, it could be that they were left by his parents during the night or it could be that they were left by Santa Claus. The former explanation should prevail until the later one is proven. Or someone talks to the dead: either they are con artists (Randi has duplicated all such feats with simple trickery) or they really do talk to the dead.

To see the memorable clip where Tonight show host Don Lane threw a hissy fit with Randi for suggesting that Lane’s favourite, Doris Stokes, didn’t really talk to the dead, see:

Another interesting website to visit is that of the Australian Skeptics:

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