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PresumptionAKA: Domino Fallacy

The Slippery Slope Fallacy

Claims a small first step will inevitably lead to extreme outcomes.

Quick summary
  • Definition: Claims a small first step will inevitably lead to extreme outcomes.
  • Impact: Slippery Slope distorts reasoning by It skips showing causal links between each step. Possibility is treated as certainty.
  • Identify: Look for patterns like If X happens, then maybe Y will happen.

What is the Slippery Slope fallacy?

A slippery slope asserts that allowing X will trigger a chain of worsening events, without demonstrating that the chain is likely or unavoidable.

People lean on this pattern because Predicting doom can sound cautious and can block change without evaluating real risks.

The Pattern
  • 1If X happens, then maybe Y will happen.
  • 2Assume Y leads to Z, an extreme outcome.
  • 3Treat Z as inevitable, not just possible.

Why the Slippery Slope fallacy matters

This fallacy distorts reasoning by It skips showing causal links between each step. Possibility is treated as certainty.. It often shows up in contexts like Debate, Media, Everyday conversation, where quick takes and ambiguity can hide weak arguments.

Examples of Slippery Slope in Everyday Life

Everyday Scenario
"Discussing flexible work hours."
A:“Could we allow one remote day per week?”
B:“If we start that, soon nobody will come to the office at all.”
Serious Context

A city argues that permitting limited street vending will ‘inevitably’ destroy all brick-and-mortar businesses, without evidence for the cascade.

Why it is fallacious

It skips showing causal links between each step. Possibility is treated as certainty.

Why people use it

Predicting doom can sound cautious and can block change without evaluating real risks.

How to Counter It

Recognition

  • A chain of events is asserted with little evidence for each link.
  • Language of inevitability (“will”, “inevitable”) is used for speculative steps.
  • No consideration of safeguards that would break the chain.

Response

  • Ask for evidence connecting each step in the chain.
  • Identify stopgaps or policies that prevent the extreme outcome.
  • Distinguish between possibility and probability.
Common phrases that signal this fallacy
  • “Slippery Slope” style claim: Claims a small first step will inevitably lead to extreme outcomes.
  • Watch for phrasing that skips evidence, e.g. "Claims a small first step will inevitably lead to extreme outcomes"
  • Pattern hint: If X happens, then maybe Y will happen.
Better reasoning / Repair the argument

Ask for evidence connecting each step in the chain.

Often confused with

Slippery Slope is often mistaken for Appeal to Emotion, but the patterns differ. Compare the steps above to see why this fallacy misleads in its own way.

Variants

Close variations that are easy to confuse with Slippery Slope.

Frequently Asked Questions

Is Slippery Slope always invalid?

Slippery Slope signals a weak reasoning pattern. Even if the conclusion is true, the path to it is unreliable and should be rebuilt with sound support.

How does Slippery Slope differ from Appeal to Emotion?

Slippery Slope follows the pattern listed here, while Appeal to Emotion fails in a different way. Looking at the pattern helps choose the right diagnosis.

Where does Slippery Slope commonly appear?

You will find it in everyday debates, opinion columns, marketing claims, and quick social posts—anywhere speed or emotion encourages shortcuts.

Can Slippery Slope ever be reasonable?

It can feel persuasive, but it remains logically weak. A careful version should replace the fallacious step with evidence or valid structure.

Further reading