False Cause
Also known as: post hoc ergo propter hoc, correlation is not causation
Assuming that because one thing happened after another, or alongside it, the first must have caused the second.
Examples
A recreational soccer player has a great match after trying a new pair of socks.
Theo: “I wore my new socks and we won 4-1. I’m wearing them every game now.”
The socks were worn right before the win, but nothing connects sock choice to passing accuracy or teamwork. Theo has mistaken sequence — one thing happening before another — for cause.
A similar mix-up shows up in data shared online, usually with a chart:
Post: “Ice cream sales and drowning deaths rise and fall together every year. Coincidence? I think not.” Reply: “Ban ice cream trucks near pools!”
Both ice cream sales and drownings rise in summer because of a third factor — warmer weather means more swimming and more ice cream, not that one causes the other. That hidden third variable is called a confounder.
Why the reasoning fails
False cause skips the actual work of establishing causation and substitutes something much weaker: timing or co-occurrence. “A happened, then B happened” or “A and B move together” are both real observations, but neither one, by itself, shows that A produced B. There are always other explanations to rule out first — coincidence, a shared underlying cause, or the causation running the other way. Sequence and correlation are where a causal investigation begins, not where it ends. A genuine causal claim needs a mechanism, a controlled comparison, or the ruling-out of alternative explanations — not just a shared timeline.
How to respond
- Ask what the mechanism would be: “What’s the actual link between the socks and how the team played?”
- Look for a third factor: “Could something else explain both going up at the same time?”
- Distinguish it from an established cause. When a mechanism is known and tested — smoking damaging lung tissue, for instance — that’s not false cause, it’s evidence-backed causation.
- Don’t demand certainty for every reasonable hypothesis. “Let’s check whether A causes B” is fine; the fallacy is skipping straight to “A causes B” without checking.