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False cause
Assuming that because one thing followed another, the first caused it.
Also known as
Post hoc ergo propter hocCorrelation vs causationNon causa pro causa
The shape of the move
A happened, then B happened (or A and B occur together). Therefore A caused B.
What is the false cause fallacy?
False cause confuses sequence or correlation with causation. Two things happening together, or one after the other, doesn't prove that one caused the other.
There may be a third factor causing both (ice cream sales and drownings both rise in summer), the causation may run the other way, or it may be coincidence.
Examples
Sport
“I wore my lucky shirt and we won, so the shirt helps.”
Why it fails: Wearing the shirt and winning merely happened together.
Health
“Countries that eat more chocolate win more Nobel prizes, so chocolate makes you smarter.”
Why it fails: Wealth likely drives both.
In a debate
“We hired a new coach and started losing — he's the reason.”
Why it fails: Injuries, opponents, or chance could explain it.
Why it feels convincing
Our brains are pattern-finders, built to spot causes quickly. That instinct is useful but often fires on coincidences.
Spot it: Sequence or correlation is presented as proof of cause.
In the arena
If you’re about to commit it
- Ask whether a third factor could explain both.
- Look for controlled studies, not just correlations.
- Explain the mechanism — HOW does A cause B?
Instead of
“Since the new phone law, accidents dropped, so the law worked.”
Try
“Accidents dropped 12% after the law, while neighbouring states without it saw no change — that comparison suggests the law had an effect.”
If your opponent commits it
- Offer an alternative explanation or third factor.
- Ask for a mechanism or a controlled comparison.
- Point out reverse causation if it fits.
Say this
“Those two things happening together doesn't prove one caused the other. What rules out other explanations?”
When it’s not a fallacy
Inferring causation is fine when there's a controlled comparison, a clear mechanism, or consistent evidence across many studies — that's how science establishes cause.
How the Oracle scores it
In an Arguen match, every argument is scored out of 80 across Clarity, Evidence, Logic and Rebuttal. If the Oracle detects a false cause, it subtracts a penalty and puts the fallacy on your scorecard with the exact quote and a one-sentence explanation — so you see precisely where the chain snapped.
Frequently asked questions
What does post hoc ergo propter hoc mean?
"After this, therefore because of this" — assuming that because B followed A, A caused B.
Does correlation ever imply causation?
Not on its own. Correlation is a clue; causation needs a mechanism, controls, or experiments.