Slippery slope

In the contexts of debate or of rhetoric, the phrase slippery slope, also appearing as the thin end of the wedge or the camel's nose, refers both to an argument about the likelihood of one event given another, and to a fallacy about the inevitability of one event given another. Invoking the "slippery slope" means predicting (without necessary justification) that one step in a process will lead unavoidably to a second (generally undesirable) step.

Contents

Argument

The argument occurs in the following context: A, B denote events, situations, policies, actions etc. Within this context, the proposer posits the following inferential scheme:

If A occurs
B is more likely to occur

The argument takes on one of various semantical forms:

  • In one form, it is that argued by making a move in a particular direction, we start down a "slippery slope" in which it is likely that we will continue in the same direction (usually seen by the arguer as a negative direction; hence the "sliding downwards" metaphor).
  • The other form appears more static, arguing that admitting or permitting A leads to admitting or permitting B, by following a long chain of logical relationships.

Examples

For example: many civil libertarians argue that even minor increases in government authority, by making them seem less noteworthy, make future increases in that authority more likely: what would once have seemed a huge power grab, the argument goes, now becomes seen as just another incremental increase, and thus appears more palatable (see here (http://www.eff.org/effector/HTML/effect15.36.html#IV) for a specific example).

Eugene Volokh's Mechanisms of the Slippery Slope (http://www1.law.ucla.edu/~volokh/slippery.htm) (PDF version (http://www.law.ucla.edu/faculty/volokh/slippery.pdf)) 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 who to confiscate them from.
  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 of the Constitution of the United States. 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: People may ignore gun registration because 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.

Fallacy

The slippery slope argument may or may not involve a fallacy. See the discussion on the two interpretative paradigms below: the momentum paradigm and the inductive paradigm. However the slippery slope claim requires independent justification to connect the inevitability of B to an occurrence of A. Otherwise the slippery slope scheme merely serves as a device of sophistry.

Often proponents of a "slippery slope" contention propose a long series of intermediate events as the mechanism of connection leading from A to B. The "camel's nose" provides one example of this: once a camel has managed to place its nose within a tent, the rest of the camel will inevitably follow. In this sense the slippery slope resembles the genetic fallacy, but in reverse.

Arguers also often link the slippery slope fallacy to the straw man fallacy in order to attack the initial position:

  1. A has occurred (or will or might occur); therefore
  2. B will inevitably happen. (slippery slope)
  3. B is wrong; therefore
  4. A is wrong. (straw man)

This form of argument often provides evaluative judgements on social change: once an exception is made to some rule, nothing will hold back further, more egregious exceptions to that rule.

Note that these arguments may indeed have validity, but they require some independent justification of the connection between their terms: otherwise the argument (as a logical tool) remains fallacious.

The "slippery slope" approach may also relate to the conjunction fallacy: with a long string of steps leading to an undesirable conclusion, the chance of all the steps actually occurring is actually less than the chance of any one individual step occurring alone.

Contemporary examples of the slippery slope fallacy may include:

  • If we allow women to abort their unborn children, then soon no life will be held sacred.
  • If we forbid partial-birth abortion, soon all abortion will become illegal.
  • If we allow gun registration, then gun confiscation will follow.
  • Use of 'soft' drugs such as cannabis will inevitably lead to addiction to 'harder' drugs such as heroin.
  • If we allow gay marriage, people will soon want to marry children and animals as well.

Semantic forms of the slippery slope

At least two forms of semantics for the slippery slope argument exist: the momentum semantics and the induction semantics.

Momentum

In the momentum interpretation, the occurrence of event A will initiate a process which will lead inevitably to occurrence of event B. The process may involve causal relationships between intermediate events, but in any case the slippery slope schema depends for its soundness on the validity of some analogue for the physical principle of momentum. This often takes the form of a domino theory or contagion formulation. The domino theory principle may indeed explain why a chain of dominos collapses, but an independent argument is necessary to explain why a similar principle would hold in other circumstances. To achieve this one might (for example) establish an abstract model for the terms that occur in the argument, in which the momentum principle obtains. This leaves showing the validity of the abstract model as a separate intellectual exercise.

Induction

The other interpretation resembles mathematical induction. Consider the context of making evaluative (or accessibility) judgements (good or bad, permit or deny) on each one of a class of events or situations. Assume these events can be arranged in an infinite sequence

A1, A2, A3.., Ak,..

such that for each k, event Ak differs from Ak+1 in a uniform way and the difference between events A2 and A1 is small.

Moreover, the following evaluations are given:

  • An is considered harmful for some large value of n.

By uniformity, it follows that the difference between Ak+1 and Ak for k=1,2,3, ... is small. In particular, Ak+1 should receive the same evaluation as Ak. Therefore by iterating this process we deduce:

  • For any k=1,2,3,..., Ak should have the same evaluation as A1.
  • Therefore A1 should be considered harmful.

For example, the following arguments fit the slippery slope scheme with the inductive interpretation

  • If we grant a building permit to build a Mosque (Pentecostal Church, Temple) in our community, then there will be no bound on the number of building permits we will have to grant for Mosques (Pentecostal Churches, Temples) and the nature of this city will change. This argument instantiates the slippery slope scheme as follows: Ak is the situation in which k building permits are issued. One first argues that going from the situation of k permits issued to k+1 permits issued is no different than from going from 1 to 2. One such argument could run as follows: for arbitrary k>1, we are adding a Mosque (Pentecostal Church, Temple) in an environment where at least one already exists which is similar to the case k=1. Moreover, issuing permits to build 1000 Mosques (Pentecostal Churches, Temples) in a city of 300,000 will clearly change the nature of the community.
  • If we allow use of Spanish in this special class for immigrants, then there is no limit to the number of classes where we allow usage of Spanish.

The soundness of the argument can only be evaluated by appropriately formulating the semantics of the slippery slope scheme. In the naive presentation as an instance of mathematical induction, the argument is indeed clearly sound. However, in most real-world applications, including the two given above, this naive semantics fails because the inductive scheme fails for imprecisely defined predicates.

External Links

This article is licensed under the GNU Free Documentation License. It uses material from Wikipedia article. Browse Wikipedia for more information.