Steelman
Post hoc
Also called post hoc, ergo propter hoc (“after this, therefore because of this”), false cause, post hoc fallacy.
Assuming that because B followed A, A caused B.
What it is
Concluding that one event caused another merely because it happened first.
The pattern
A happened, then B happened. Therefore A caused B.
An example
“I wore my lucky socks and we won. The socks work.”
The win came after the socks, but nothing connects them. You’d need to compare many games with and without the socks, and even then games vary a lot.
Why it fails
A cause must come before its effect, but coming first is nowhere near enough. B might have happened anyway, A and B might share a cause, or the timing might be coincidence. Establishing cause takes more, such as a comparison group, a plausible mechanism, or a repeatable pattern that rules out alternatives.
When it’s not a fallacy
Most lists skip this part. Calling a fair point a fallacy is a mistake too.
It can be fair when
- The timing is combined with other evidence: controlled experiments, a known mechanism, a dose-response pattern, or alternatives ruled out. Correlations often are good evidence of causation; the fallacy is leaping to it hastily.
Try one
A question from the app. The wrong answers are its usual look-alikes.
Team chat. Dana: “Heads up for the board deck: Q1 is our slow quarter every year, and Q2 is when the spring orders land.” Rob: “We came back to the office in March, and Q2 sales jumped 12%. Say what you want about the commute, having everyone in one room works.” Dana: “Noted. Send me the March numbers when you get a sec.”
What’s the flaw?
Dana just said Q2 beats Q1 every year because of spring orders. Rob credits the return to the office for a jump that comes every spring anyway.
A fair reply
“Q2 always jumps, though. How did this one compare with last year’s Q2?”
Often confused with
- Correlation is not causation
Cum hoc infers cause from two things occurring together. Post hoc infers it from one following the other.
- Regression fallacy
The regression fallacy is a special case: something extreme returns toward normal, and whatever happened in between gets the credit.
Where the name comes from
Post hoc is Latin for “after this”, the same post as in “postgame”. The full phrase, post hoc, ergo propter hoc, means “after this, therefore because of this”, which spells out the whole mistake. Post hoc fallacy is the short name. False cause is a wider label for blaming the wrong cause, and post hoc is the version built on timing.
Sources
- Fallacies, Bradley Dowden, Internet Encyclopedia of Philosophy
In the app
Practice spotting it on arguments that sound real.
Steelman has more examples of post hoc, how to answer it in a real conversation, and practice rounds that mix it with its look-alikes, so you learn the difference, not just the name. Coming soon to iPhone and Android.
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