Understanding Occam’s Razor
Introduction
This post is all about razors, not razors that one uses to shave, but the philosophical ones, more specifically, the Occam’s Razor.
According to Wikipedia, a philosophical razor is a principle or rule of thumb that allows one to eliminate (“shave off”) unlikely explanations for a phenomenon.
Understanding Razors
Why are razors important to understand? They can be so very important because of their ability to shave off complex problems using heuristics to enable us to take better decisions. Some problem too complex? Try using razors to simplify it. It’s easier said than done though. One needs to practice using them in different situations.
Razors have been around for almost two millennia. Occam’s razor, in particular, is attributed to William of Ockham who lived during the late 1200s but the idea has been around since Aristotle’s time. (Also see Lindy Effect).
So, what is the Occam’s Razor?
Among competing hypotheses, the one with the fewest assumptions should be selected.
This basically means that when faced with competing hypotheses, select the one that makes the fewest assumptions and is thus most open to being tested and do not multiply entities without necessity.
This was of course, propounded many times before him, but it was attributed to him because of his frequency of usage of this principle. When I first came across this, it was quite tricky to understand and apply — so I use a more recent formulation of this principle. This is Theodore Woodward’s dictum that states:
When you hear hoofbeats, think of horses not zebras
The principle is based on two other principles, namely — the principle of plurality (plurality should not be posited without necessity) and the principle of parsimony (It is pointless to do with more what is done with less).
It’s important to remember that Occam’s razor proves nothing. It serves instead as a heuristic device — a guide or a suggestion — that states that when given two explanations for the same thing, the simpler one is usually the correct one.
Problems
There are two problems with using Occam’s razor as a tool to prove or disprove an explanation. One, determining the whether a solution is simple is subjective as it is up to the interpreter to decide whether it is simple or not. Two, just because it is simple doesn’t necessarily mean it’s the truth.
There was a great example I saw when I was researching this stuff. It does like this:
“There are some creationists who say that Occam’s razor proves their ideology is correct. After all, isn’t it a more simple explanation to say that God created life, the universe and everything than to say it was created by a Big Bang, followed by an astounding series of interrelated coincidences?”
“That explanation supposes that God exists, and we have no empirical evidence that he does.”
Conclusion
In practice, Occam’s Razor is used to cut away elements of theories which cannot be observed. One must remember that it doesn’t necessarily prove that one theory is correct.
Check out other razors (Source: Wikipedia):
- Occam’s razor: When faced with competing hypotheses, select the one that makes the fewest assumptions and is thus most open to being tested. Do not multiply entities without necessity.
- Grice’s razor: As a principle of parsimony, conversational implications are to be preferred over semantic context for linguistic explanations.
- Hanlon’s razor: Never attribute to malice that which can be adequately explained by stupidity.
- Hume’s razor: “If the cause, assigned for any effect, be not sufficient to produce it, we must either reject that cause, or add to it such qualities as will give it a just proportion to the effect.”
- Hitchens’ razor: “What can be asserted without evidence can be dismissed without evidence.”
- Alder’s razor: Also known as “Newton’s flaming laser sword”, it states that if something cannot be settled by experiment or observation then it is not worthy of debate.
- Popper’s falsifiability principle: For a theory to be considered scientific, it must be falsifiable.
- Rand’s razor: concepts are not to be multiplied beyond necessity — the corollary of which is: nor are they to be integrated in disregard of necessity.
- Darwin’s Razor
