What IS occam's razor?

[sorgoth]

I've heard it mentioned many times, but no idea what it is other than being some weird-ass theory. Explain, please.

 

[UserGoogol]

Its not a theory, but a philosophy. Skeptical Dictionary's definition of Occam's Razor

In general, it seems to be the belief that a theory should have as few assumptions about the world as possible. Which seems perfectly sensible.

~User "My sig is hand written, but short" Googol~

 

[Guest]

If theory A has M assumptions and explains event E
T(A,M)~E

and

theory B has N assumptions and explains the same event E
T(B,N)~E


Theory A is more desirable iff M is less than N.

 

[rwald]

In simple terms, "The simplest theory which explains all the data is assumed to be correct (until more data comes along to disprove it)."

 

[boooeee]

In even simpler terms, "Keep it Simple, Stupid"

 

[Cecil]

In simple terms, "The simplest theory which explains all the data is assumed to be correct (until more data comes along to disprove it)."

Originally posted by boooeee In even simpler terms, "Keep it Simple, Stupid"

KISS is more simple.

(Point of note, which is simpler, "simpler" or "more simple"? The former is only one word, but it also requires a conjugation.)

 

[Frostbite]

It means the most likely solution to a problem is probably it. I call it intellectual laziness.

 

[SpaceLord]

It means the most likely solution to a problem is probably it. I call it intellectual laziness.

Why is it lazy? I'd like a explanation instead of an assertion.

 

[Bobo]

It means the most likely solution to a problem is probably it. I call it intellectual laziness.

I'm not sure I'd call it laziness.

The premise behind the philosophy is that you've created (or researched) multiple theories to explain something and the simplest one should be investigated further. That would indicate intellectual stamina.

Bobo

 

[RichardR]

It does not mean choose the simplest, although many people (including some here apparently), will tell you it does. It actually means don't invent unnecessary entiities to explain something that can be explained without them.

Please read this explanation and come back with any questions.

 

[arcticpenguin]

Those who do not accept Occam's Razor are the lazy ones. If a simpler explanation than their's accounts for the evidence, then it should be up to them to supply more evidence. If they are unwilling to do so, then they are lazy.

 

[Keneke]

Then, there's the other side of it I made up called Occam's Duct Tape. Sometimes people like to put simple explanations on things when there is a logical, yet complex, answer. I used it in that dream precognition thread we had.

Previous definitions do not explain a common phrasing of the theory: "All other things being equal, etc." That is, longer explanations do not mean more thought, time or more scientific processes have been put into the formulation of the hypothesis. Of course, this contradicts the intuitive notion that the more time and effort you spend on something (which people assume with large, complex hypotheses), the more chance you have of doing it right.

The problem here is when people use Occam's Razor incorrectly. It is said (in that link) that some people use the razor to slash out the whole existence of God. However, "all other things" are not equal. Positions on God-created phenomena, such as the new Earth theory, do not have the scientific success of repeatability, such as evolution does. Therefore, all other things are NOT equal, therefore, Occam's Razor does not apply.

Also, Occam's Razor is a theory for the probability of a certain phenomenon existing, and not a proof in itself. One cannot prove anything if their proof includes an assumption like Occam's Razor. That is another way Occam's Razor can be misused.

Also again, (and let me get cosmic with you for a second), how can we know "all other things are equal"? What if there is some scientific experimentation data that we have not collected yet? If you use Occam's Razor to disprove X today, what if we find data on X tomorrow that changes all that? We cannot know all of anything, therefore we may not know that all other things are truly equal.

To approach another definition ("Plurality should not be used without necessity") the same way, what is necessity? In scientific research, when comparing one theory to another in the same field, have we ALWAYS found that the smaller, simpler theory is correct? Maybe not, you might say, there might have been a case where the simpler theory was just incorrect. Therefore, the longer, more correct theory was necessary. If so, how can we know that theories of differing length have the exact same amount of correctness in them? Would not a theory, in time, be proven more or less valuable to science by research and investigation alone? Why do we need something so redundant?

So, lazy people can and do use Occam's Razor just like any other logical fallacy. It is an assumption of a theory's correctness based upon its relative complexity to simpler versions of itself.

Now then, just because it has these flaws doesn't mean we shouldn't use it. We just have to use it correctly. It is great for estimating the probability of the correctness of a theory, for simplicity reigns in most, if not all, scientific principles. We just have to make sure and not use it as proof of anything, only probability.

 

[DrMatt]

It means the most likely solution to a problem is probably it. I call it intellectual laziness.

Sometimes it takes a lot of intellectual work to see through and explain your way through explanations which introduce extraneous suppositions, actually.

 

[RichardR]

Then, there's the other side of it I made up called Occam's Duct Tape. Sometimes people like to put simple explanations on things when there is a logical, yet complex, answer. I used it in that dream precognition thread we had.

Occam’s Razor says nothing about simple v. complex. You are mis-using it, it seems to me.

Previous definitions do not explain a common phrasing of the theory: "All other things being equal, etc." That is, longer explanations do not mean more thought, time or more scientific processes have been put into the formulation of the hypothesis. Of course, this contradicts the intuitive notion that the more time and effort you spend on something (which people assume with large, complex hypotheses), the more chance you have of doing it right.

The problem here is when people use Occam's Razor incorrectly. It is said (in that link) that some people use the razor to slash out the whole existence of God. However, "all other things" are not equal. Positions on God-created phenomena, such as the new Earth theory, do not have the scientific success of repeatability, such as evolution does. Therefore, all other things are NOT equal, therefore, Occam's Razor does not apply.

What are you talking about? There is no "All other things being equal, etc." in Occam’s Razor.

Also, Occam's Razor is a theory for the probability of a certain phenomenon existing,

Except that it is not a theory and it says nothing about the probabilities of anything existing.

and not a proof in itself. One cannot prove anything if their proof includes an assumption like Occam's Razor. That is another way Occam's Razor can be misused.

True. It just says don’t make things up if you don’t need them.

Also again, (and let me get cosmic with you for a second), how can we know "all other things are equal"? What if there is some scientific experimentation data that we have not collected yet? If you use Occam's Razor to disprove X today, what if we find data on X tomorrow that changes all that? We cannot know all of anything, therefore we may not know that all other things are truly equal.

Again, "all other things are equal" has nothing to do with it. However, your “What if there is some scientific experimentation data that we have not collected yet?” is the crux of it. Occam’s Razor tells us not to decide what that data is before it has been collected. What's wrong with that?

To approach another definition ("Plurality should not be used without necessity").

Actually, that is the definition, not another definition

the same way, what is necessity? In scientific research, when comparing one theory to another in the same field, have we ALWAYS found that the smaller, simpler theory is correct? Maybe not, you might say, there might have been a case where the simpler theory was just incorrect. Therefore, the longer, more correct theory was necessary. If so, how can we know that theories of differing length have the exact same amount of correctness in them? Would not a theory, in time, be proven more or less valuable to science by research and investigation alone? Why do we need something so redundant?

Again, it’s nothing to do with simplest or shortest.

And please tell me why you think it is redundant.

So, lazy people can and do use Occam's Razor just like any other logical fallacy. It is an assumption of a theory's correctness based upon its relative complexity to simpler versions of itself.

It is not lazy and it is not a logical fallacy. It is not what you state it is.

 

[Frostbite]

Bah. What I mean is, it's lazy to say "There is no need for God therefore he must not exist" when it's far less involving to say "I have no idea if he does or doesn't, let's investigate!". God might be a freak occurrence, as are many other things, and Occam's Razor ignores freak occurrences and only focuses on the more likely statistical possibility.

 

[RichardR]

Bah. What I mean is, it's lazy to say "There is no need for God therefore he must not exist" when it's far less involving to say "I have no idea if he does or doesn't, let's investigate!".

That’s the wrong way to view Occam’s Razor.

It says, if something can be explained naturally (that is, using entities that are known to exist), then there is no need to include God (or anything else which is not known to exist), in the explanation. Therefore, if you say God is necessary you are doing so because you want to, not because it is really necessary. If you go this route, you might just as easily say that a pink giraffe that lives on the Moon is necessary for the explanation. Why choose God over the pink giraffe if there is no proof for either and no need for either to explain the phenomenon?

God might be a freak occurrence, as are many other things, and Occam's Razor ignores freak occurrences and only focuses on the more likely statistical possibility.

It’s nothing to do with statistical probabilities. It is about not making up an unnecessary entity.

 

[Frostbite]

God was just an example. A bad example perhaps, but whatever. If criminal investigators used Occam's Razor in their reasoning, their investigations wouldn't take years or months...

 

[Keneke]

Occam’s Razor says nothing about simple v. complex. You are mis-using it, it seems to me.

Ah, I see. Using your linked example, (cat vs. milk fairy) Occam's Razor would discredit the milk fairy theory. However, by what you are saying, Occam's Razor would have no effect on the cat vs. a stray cat who habitually comes in through the cat door. The second theory is more complex, yet assuming these conditions are not invented (the stray does come in every day, there really is a cat door), Occam's Razor then has nothing to do with it.

(PS Occam's Duct Tape is a joke. Sorry if it was too subtle.)

What are you talking about? There is no "All other things being equal, etc." in Occam’s Razor.

I'm talking about the common version that you hear in pop culture, such as the movie Contact: "All other things being equal, the most succinct answer is usually the right one." However, seeing as how different definitions can be misinterpreted (the movie version deals with complexity, not invention), let's stick to the ones that have been posted here.

By the way, do you think that this corruption of the theory should be given it's own name (whether a theory or a fallacy) in order to distinguish itself from Occam's Razor?

Except that it is not a theory

If it's not a theory, what is it? It's not a proof. A guideline, perhaps?

and it says nothing about the probabilities of anything existing.

I say probability because, using the definition in the link you supplied, "...there is a plausible explanation that does not require the milk fairy - the cat." Therefore, the author implies that the cat is a plausible reason. More likely. Higher probability. True, the science of probability cannot be strictly applied to give a percentage, but in the most general terms, the cat is more likely to be the answer than the milk fairy. The problem here is that the original Latin translation is "Should not" but the modern English version given is "Do not". The change has made it from a suggestion or hypothesis into a proof.

Also, your linked essay says, "Note: we haven't proven that the cat drank the milk." That means Occam's Razor is NOT a proof. Perhaps the wording of the modern version should be altered slightly to reflect this.

And please tell me why you think it is redundant.

Occam's Razor can be redundant because we are attempting to determine something that eventually, in time, we will discover through scientific means. Now then, that doesn't mean it's not important in predicting correctness. If used correctly, Occam's Razor is a great tool. However, the mistake is that people use it as proof, which should not replace scientific scrutiny and also is an incorrect usage.

It is not lazy and it is not a logical fallacy. It is not what you state it is.

Technically true. The theory itself, when used, does not render the user lazy, but rather lazy application of the theory can produce illogical effects. Let me correct myself. I shall say "Lazy people use Occam's Razor as proof, though the theory itself is not a water-tight solution. Such misinterpretation is a logical fallacy."

Why choose God over the pink giraffe if there is no proof for either and no need for either to explain the phenomenon?

Which is the greater invention? I hope it is a moot point, I certainly don't want to start keeping score of this stuff now.

 

[toddjh]

God was just an example. A bad example perhaps, but whatever. If criminal investigators used Occam's Razor in their reasoning, their investigations wouldn't take years or months...

Reading your replies in this thread, I don't think you quite understand Occam's razor. It's not about assuming things are true or false. It's about not assuming anything that you don't need to.

You mentioned criminal investigation, so let's take an example from there. Suppose you find a man shot dead, with a gun in his hand. Was it suicide or murder? As an investigator, you might assume, for the sake of argument, that his wife killed him and tried to make it look like a suicide, and then look for evidence to support that.

But that's not the situation that Occam's razor applies to. In that case, you have two competing theories: the suicide theory, and the murder theory. The theories are not equal: the evidence might support one and not the other (and, in fact, probably will).

Occam's razor only talks about situations where the two competing theories are equivalent -- where there is no evidence that could show which one was true. That's why you hear "all else being equal" so much in casual conversation about it. It simply doesn't apply in situations where further investigation could reveal which of two competing theories is correct.

Jeremy

 

[Keneke]

If criminal investigators used Occam's Razor in their reasoning, their investigations wouldn't take years or months...

I doubt it. Investigators aren't always stupid.