Definition
Post Hoc Ergo Propter Hoc (Latin for "after this, therefore because of this") is a logical fallacy that assumes a causal relationship between two events simply because one follows the other in time. It mistakes correlation for causation.
Examples
Example 1: Superstitions
"I wore my lucky socks and then aced the test. The socks must have caused my success!"
Example 2: Political Claims
"After the new mayor took office, crime rates dropped. The mayor must be responsible for the decrease."
Example 3: Health Myths
"I started eating kale and my headaches went away. Kale cured my headaches."
Why It's Flawed
The Post Hoc Ergo Propter Hoc fallacy is flawed because:
- It confuses correlation with causation
- Other factors may explain the outcome
- It ignores possible coincidences
- It oversimplifies complex situations
Sound reasoning requires evidence of causation, not just temporal order.
How to Spot It
Look for these signs of the Post Hoc fallacy:
- The argument assumes causation just because one event follows another
- No evidence is provided for a causal link
- Alternative explanations are ignored
- The argument relies on coincidence or timing
Example of spotting it: If someone claims "I took vitamin C and my cold went away," ask if the cold might have ended on its own or if other factors were involved.
How to Avoid It
To avoid using or being misled by the Post Hoc fallacy:
- Look for actual evidence of causation, not just timing
- Consider alternative explanations
- Avoid jumping to conclusions based on coincidence
- Ask for supporting data or research
When evaluating a claim, focus on whether a true causal connection is established, not just temporal sequence.