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No. 282 · Evidence · Fallacy

Slippery Slope

A first step does not lead to disaster unless every link in the chain holds.

The Slippery Slope argues that a small action will set off a chain reaction ending in catastrophe, without showing why each step must follow. Eisenhower's domino theory predicted a wave of collapses in Southeast Asia that largely did not happen.

When someone predicts disaster from a first step, ask them to spell out each link. Some slopes are real, though, so instead of refusing every step, set clear guardrails that stop the slide where you choose.

In the Almanac

“The falling dominoes”, 1954 · “Cloudflare”, 2017

Both stories in full, three ways to use it and where it misleads.

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Slippery Slope: When Arguments Take a Tumble

Questions

What is Slippery Slope?

The Slippery Slope argues that a small action will set off a chain reaction ending in catastrophe, without showing why each step must follow. Eisenhower's domino theory predicted a wave of collapses in Southeast Asia that largely did not happen.

How do you avoid Slippery Slope?

When someone predicts disaster from a first step, ask them to spell out each link. Some slopes are real, though, so instead of refusing every step, set clear guardrails that stop the slide where you choose.

When does Slippery Slope matter?

Slippery Slope is one of the 68 mental models for evidence, the situations where you ask: Is this really true? Within that, it belongs to “Spotting a bad argument”, alongside Ad Hominem, Appeal to Authority and Appeal to Emotion.

What is an example of Slippery Slope?

Two stories show it at work: The falling dominoes (1954) and Cloudflare (2017). Both are told in full in The Mental Models Daily Almanac, which has two stories for each of its 365 models.

Which mental models are related to Slippery Slope?

Domino Effect, Gateway Drug Theory and Compounding Effect. Slippery Slope itself comes from fallacy.