Piera is firmly against legalizing marijuana. “After all,” she argues, “if we legalize marijuana, it follows that restrictions on other substances would also loosen. From there, it isn’t long before all drugs are legalized. People will be doing hard drugs all the time. Everyone becomes an addict, and the market crashes. Civilization as we know it will be gone.”
Piera argues that legalizing marijuana is the first step leading to the destruction of civilization. Since we should probably avoid the destruction of civilization, we should therefore also avoid the legalization of marijuana. However, she never actually proves that these two events are causally related. It seems pretty unlikely that legalizing weed would be the downfall for a civilization. Thus she commits the fallacy of the slippery slope.
Definition/ Slippery Slope
The slippery slope is a logical fallacy in which a relatively small claim is asserted to inevitably lead to a significant event that must be avoided. Despite the initial assertion, little to no evidence is actually given to support or prove the causality of this relationship. The slippery slope can have many in-betweens from the first claim and its final predicted disaster, but only the claim and prediction are needed for the assertion to be a slippery slope. In essence, the argument becomes an appeal to the probability fallacy: the audience is asked to act as if a highly unlikely event will definitely occur.
The term “slippery slope” is first recorded being used in 1951. The slippery slope is also known as absurd extrapolation, the thin edge of the wedge, camel’s nose, and domino fallacy. Rather than directly engaging with the issue at hand, the slippery slope fallacy shifts focus to extreme hypotheticals. Just like its name, it proposes that this one misstep will cause everything to topple and crash: thus that step must be avoided at all costs.
Despite being a logical fallacy, slippery slope arguments can be very persuasive. They work off fear and use that powerful emotion as leverage. The point becomes tainted by unfair conjecture and invalidated based on absurd unsupported claims.
Slippery slope arguments are commonly used in all forms of debate, which is precisely why they can be so dangerous. If they aren’t recognized as logical fallacies and are taken seriously, actual discussion with reasoning is cast aside in favor of senseless fear.
They can be particularly frustrating because slippery slope arguments are generally used by opponents who lack evidence to support their positions. Absurd extrapolation can signal a lack of understanding of the speaker on the topic. If you find someone trying to use the domino fallacy against you, point out the lack of evidence in the claim while providing evidence linking your position with positive benefits.
It is essential when claiming a link between two events, or a chain of events, that you provide evidence. Show a causal relationship with mathematical, logical, and or physical certainty to support your claim.