What is The Post Hoc Fallacy? | Critical Thinking Basics


Explanation. Examples. How to avoid the Post Hoc Fallacy fallacy.

What the Post Hoc fallacy is:

The Post Hoc fallacy, also known as post hoc ergo propter hoc (“after this, therefore because of this”), occurs when one assumes that because one event precedes another, it must be the cause of the second event.

When it occurs:

This fallacy occurs when a causal connection is established merely based on the temporal sequence of events.

Why it helps to identify and manage it:

Identifying the Post Hoc fallacy is crucial for accurate reasoning, as it prevents the erroneous attribution of causation based solely on temporal sequence. Managing this fallacy encourages a more thorough investigation into potential causal relationships, promoting sound decision-making.

How to manage the Post Hoc fallacy:

To address the Post Hoc fallacy, prompt a critical examination of potential alternative explanations or intervening variables that could account for the observed sequence of events. Emphasize the importance of empirical evidence and scientific reasoning to establish causal connections rather than relying on temporal correlation alone. Encouraging a more rigorous approach to causation enhances the validity of arguments and decision-making processes.

Post-Hoc Fallacy: Examples

  1. “I wore my lucky socks, and we won the game; therefore, my socks brought us victory.”
  2. “The rooster crowed, and then the sun rose; therefore, the rooster caused the sunrise.”
  3. “After I took the herbal remedy, my cold went away; thus, the remedy cured my cold.”
  4. “I ate ice cream before my exam, and I passed; hence, the ice cream must have boosted my performance.”
  5. “I prayed for good weather, and it didn’t rain; therefore, my prayers influenced the weather.”
  6. “The stock market crashed after the president’s speech; thus, the speech caused the market downturn.”
  7. “I walked under a ladder, and then I got a flat tire; therefore, ladders bring bad luck.”