Is Slippery Slope a Logical Fallacy?

Economics Economics Questions
1

For those logicians out there: Why is slippery slope a logical fallacy?

If such a statement can be a fallacy, is there a way to structure it so it won’t be?

Here are some examples:

http://en.wikipedia.org/wiki/Slippery_slope

Eugene Volokh’s Mechanisms of the Slippery Slope (PDF version) analyzes various types of such slippage. Volokh uses the example “gun registration may lead to gun confiscation” to describe six types of slippage:

  1. Cost-lowering: Once all gun-owners have registered their firearms, the government will know exactly from whom to confiscate them.

  2. Legal rule combination: Previously the government might need to search every house to confiscate guns, and such a search would violate the Fourth Amendment to the United States Constitution. Registration would eliminate that problem.

  3. Attitude altering: People may begin to think of gun ownership as a privilege rather than a right, and thus regard gun confiscation less seriously.

  4. Small change tolerance, colloquially referred to as the “boiling frog”: People may ignore gun registration because it constitutes just a small change, but when combined with other small changes, it could lead to the equivalent of confiscation.

  5. Political power: The hassle of registration may reduce the number of gun owners, and thus the political power of the gun-ownership bloc.

  6. Political momentum: Once the government has passed this gun law it becomes easier to pass other gun laws, including laws like confiscation.

Slippery slope can also be used as a retort to the establishment of arbitrary boundaries or limitations. For example, one might argue that rent prices must be kept to $1,000 or less a month to be affordable to tenants in an area of a city. A retort invoking the slippery slope could go in two different directions:

  • Once such price ceilings become accepted, they could be slowly lowered, eventually driving out the landlords and worsening the problem.

  • If a $1,000 monthly rent is affordable, why isn’t $1,025 or $1,050? By lumping the tenants into one abstract entity, the argument renders itself vulnerable to a slippery slope argument. A more careful argument in favor of price ceilings would statistically characterize the number of tenants who can afford housing at various levels based on income and choose a ceiling that achieves a specific goal, such as housing 80% of the working families in the area.

http://www2.law.ucla.edu/volokh/slippery.htm

Slippery slopes are, I will argue, a real cause for concern, as legal thinkers such as Madison, Jackson, Brennan, Harlan, and Black have recognized.[2] And these arguments comport at least partly with our own experience: We can all identify situations where a first step A has led to a later step B that might not have happened without A, though we may disagree about exactly which situations exhibit this quality.[3] A may not logically require B—but for political and psychological reasons, it can help bring B about.[4]

But, as legal thinkers such as Lincoln, Holmes, and Frankfurter have recognized, slippery slope arguments are of limited utility.[5] We accept, because we must, some speech restrictions. We accept some searches and seizures. We accept police departments, though creating such a department may lead to arming it, which may lead to some officers being willing to shoot innocent civilians, which may eventually lead to a police state (and all this has happened with the police in some places). Yes, each first step involves risk, but it is a risk that we need to run.

This need makes many people impatient with slippery slope arguments.[6] The slippery slope argument, the flip response goes, is the claim that “we ought not make a sound decision today, for fear of having to draw a sound distinction tomorrow.”[7] To critics of slippery slope arguments, the arguments themselves sound like a slippery slope: If you accepted this slippery slope argument, then you’d end up accepting the next one and then the next one until you eventually slip down the slope to rejecting all government power (or all change from the status quo), and thus “break down every useful institution of man.”[8] Exactly why, they ask, would accepting, say, a restriction on “ideas we hate” “sooner or later” lead to restrictions on “ideas we cherish”?[9] If the legal system is willing to protect the ideas we cherish today, why wouldn’t it still protect them tomorrow, even if we ban some other ideas in the meanwhile? And of course, even if one thinks slippery slopes are possible, what about cases where the slope seems slippery both ways—where both alternative decisions seem capable of leading to bad consequences in the future?[10]

2

Any takers? It seems all the above examples of “slippery slope” are libertarian type arguments.

From what I’m reading of these example, it would seem Friedrich Hayek’s The Road to Serfdom could be construed as one big slippery slope argument, and therefore supposedly a fallacy.

Question: Is slippery slope indeed a logical fallacy? If so, is there a way to restructure an argument such that is is not?

If not a fallacy, what is a potential defense against such an accusation?

3

It’s one of those fallacies that people sometimes get too excited in accusing people of when they’ve checked a logic book out of the library and suddenly see it everywhere. A little bit of knowledge is a dangerous thing.

The slippery slope, like many of the other fallacies, is sometimes fallacious, but sometimes not. There needs to be plausible grounds as to why we should think that this particular slippery slope is reasonable, which in Hayek’s case it most certainly is as it’s heavily substantiated.

So there’s a definite difference between a slippery slope and a fallacious slippery slope–the former is substantiated, and the latter is a bogus claim. The only defence I can think of if they don’t recognize the difference between fallacious and nonfallacious is to give a refutation by logical analogy, e.g., a slippery slope that they hold near and dear (for instance, global warming, environmentalism, and the ‘evils’ of unfettered capitalism) and take them out as well.

I think after you point that out they will clearly see that some make sense and some do not, especially when you attack his views with his own reasoning. So either see if you can get him/her to admit outright that some are fallacious and some are not or try this strategy and see if it works.

4

Thanks MrSchnapps. From what I understand, the slippery slope, as a logical structure, is fundamentally valid, and if there is a fallacy, it is not because someone uses this form of argument, but in its premises and/or application. This structure is transitive:

If A then B, if B then C, if C then D, and so on.

If someone can demonstrate there is no break in the casual chain, then the conclusion will follow the premise, then (provided the premises are true) the argument is sound.

But this form of argument is not a formal fallacy, but can be an informal fallacy if not done properly. Am I right?

5

It appears you answered your own question. If someone is accusing you of a slippery slope then you need to figure out what link in the chain they are referring to and if they can prove that link is false then they have grounds for their objection. You could, however, substitute that link in the chain for a more substantiated one and then you could start over.

6

The slippery slope is one that most people, I’ve found, end up using backwards. The slippery slope says that it’s illogical to say X leads to Z. The reason is that there can be a whole set of intermediary steps which need to be explained and justified before such a conclusion can be drawn. What most people do today, especially in popular media, is say “That’s a slippery slope and will lead to X.” But the point of the fallacy is that those people are the ones engaging in it! Let me give an example with a typical dialogue one might hear:

Person A: “Gay marriage should be legalized.”

Person B: “That’s a slippery slope, though, because then who is to say I don’t have the right to marry a turtle?”

In this dialogue, Person B, the one claiming to point out the slippery slope fallacy, is actually the one engaging in the fallacy himself. He’s drawn a conclusion of Y (you can marry a turtle) from the premise X (that gay marriage should be legalized), when in fact there are a whole list of unjustified intermediary assumptions one has to make in order for that conclusion to be sound. One assumption in this example is the difference in kind of a person and a reptile, which raises the immediate problem of a turtle’s ability to engage in a contractual relationship.

This is why it’s painful for me to watch so many media pundits jump and scream about the slippery slope fallacy when they are actually the ones engaging in the fallacy.

7

There’s a difference between saying “X will necessarily lead to Y” and saying “X may lead to Y” or (more accurately) “doing X makes it easier to do Y”. With the example of gun registration, it certainly seems true that it would be (procedurally) easier to confiscate guns if they’re registered.

8

The question you should be asking is ‘are logical fallacies a slippery slope?’

9

Those are not slippery slopes. A slippery slope is making an argument to support a specific goal whereas the argument is more general than the specific intent in the current context, leading to the eventual realization that many other similar things should be done.

Example: Someone says, health care should have no direct fee because some people can’t afford it and health care is important. Then people begin thinking about what else is important until you have the USSR.

If everyone realizes the full application from the outset it’s more like jumping off a cliff than sliding down a slippery slope.