Snopestionary: The ‘Slippery Slope’ Logical Fallacy

Logical fallacies are behind many of the harmful misunderstandings, rumors, and conspiracy theories our newsroom investigates.

  • Published
slippery slope fallacy
Image via Getty Images/Stock Illustration

Speak like an insider! Welcome to Snopes-tionary, where we’ll define a term or piece of fact-checking lingo that we use on the Snopes team. Have a term you want us to explain? Let us know.

As its name suggests, the slippery slope fallacy leads an argument through a chain of events that the arguer suggests will lead to an undesirable outcome with little or no evidence to back it up. Often with this logical fallacy, a person will accept that a proposed chain of events — in other words, the slippery slope — will happen without verifying such a likelihood. 

Example of the slippery slope fallacy:

The enactment of gun control measures in any capacity directly threatens the Second Amendment. Ultimately, the government will take away our guns and we won’t be able to protect ourselves. Therefore, gun control laws threaten and strip away our constitutional protections, and the sovereignty and freedom of Americans.

The slippery slope argument is generally used to discourage someone from affirming or taking a specific course of action on the grounds that it will lead to a worst-case-scenario outcome. In the example above, this would mean that implementing gun control measures would lead to the worst-case scenario that Americans would lose constitutional freedoms.

According to the Canadian Journal of Philosophy, there are three types of slippery slope fallacies most commonly used:

  • Causal slopes posit that one action will lead to a chain of reactions with increasingly more extreme outcomes. A minor action now will cause a major action later. 
    • For example, if I allow my child to stay up past their bedtime tonight then they will never learn to go to bed at a reasonable hour.
  • Conceptual slopes blur the lines between related issues, and posit that if there is no discernible difference between two topics then reasoning allows us to make leaps in judgment between different arguments — i.e., we can respond to two different claims or scenarios as if they’re the same. It begs the question of where does one draw the line?
    • A study published by the National Library of Medicine used legal euthanasia as an example of this type of slippery slope, arguing that some “make the claim that if some specific kind of action (such as euthanasia) is permitted, then society will be inexorably led (“down the slippery slope”) to permitting other actions that are morally wrong.”
  • Precedential slopes argue that if we treat a certain issue in one way, we will also respond to a seemingly related issue in that same manner. In this case, it’s about setting a precedent that slowly begins to degrade over time. 
    • For example, if abortion is allowed only in the event of a medical emergency, then it will be expected that all unwanted pregnancies will inevitably be terminated via abortion.

Snopes Says: In a nutshell, a slippery slope starts with a seemingly small action (or inaction) that will supposedly lead to an extreme, worst-case result. To combat this fallacy, we must first start at the first point in this chain of events. The first step in combating a slippery slope argument is to map out the chain of events and determine how likely such results are to occur. The psychology and philosophy educational website Effectiviology offers these pointers:

Point out the missing pieces of the slope. Slippery slope arguments often leave out important events that connect between the start and end points of the slope, and pointing these out can help illustrate the issues with the proposed slope.

Highlight the disconnect between the different pieces of the slope. The more disconnected the pieces of the slope are from one another, the less reasonable the slope is; this can be an issue, for example, if there is a low likelihood that a certain event will lead to the one that’s supposed to follow it.

Point out the distance between the start and end points of the slope. Demonstrating the distance between the start and end points of the slope helps illustrate why one is unlikely to lead to the other, and why it’s possible to justify treating the two in different ways.

Show that it’s possible to stop the transition between the start and end points. Explain the ways in which it’s possible to actively prevent the initial event from leading to the end event, and possibly support this by using examples of previous cases where a similar method was used.

Call out the problematic premises of the slippery slope argument. In some cases, one or more of the premises behind the slippery slope may be wrong, in which case you might benefit more from attacking the flawed premise directly, instead of addressing the issues with the slippery slope.

Provide a relevant example that illustrates the issue with slippery slope arguments in general. This approach involves attacking the concept of slippery slope arguments in general, for example by showing that they can be made in a fallacious manner with regard to nearly any possible topic, though the way you do this should preferably be related to the topic of the slippery slope argument which is being discussed.

Ask your opponent to justify the slope. If your opponent suggested a possible slope but didn’t provide any evidence which supports its validity, then you can remind them that the burden of proof rests with them, and ask them to justify why they believe that the slippery slope that they presented is reasonable.

The Snopes editorial team has been fact-checking claims centered on logical fallacies for decades. Below are examples of the slippery slope fallacy that we’ve previously investigated: 

Curious about how Snopes’ writers verify information and craft their stories for public consumption? We’ve collected some posts that help explain how we do what we do. Happy reading and let us know what else you might be interested in knowing.


Sources: 

Benatar, D. “A Legal Right to Die: Responding to Slippery Slope and Abuse Arguments.” Current Oncology, vol. 18, no. 5, Oct. 2011, pp. 206–07. PubMed Central, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3185895/.

Govier, Trudy. “What’s Wrong with Slippery Slope Arguments?” Canadian Journal of Philosophy, vol. 12, no. 2, June 1982, pp. 303–16. Cambridge University Press, https://doi.org/10.1080/00455091.1982.10715799.

“What’s Wrong with Slippery Slope Arguments?” Canadian Journal of Philosophy, vol. 12, no. 2, June 1982, pp. 303–16. DOI.org (Crossref), https://doi.org/10.1080/00455091.1982.10715799.

Slippery Slope: What It Is and How to Respond to It – Effectiviology. https://effectiviology.com/slippery-slope/. Accessed 30 May 2022.

https://effectiviology.com/slippery-slope/. Accessed 30 May 2022.

Slippery-Slope. Slippery Slope. 15 May 2019, //www.txstate.edu/philosophy/resources/fallacy-definitions/Slippery-Slope.html.