Post hoc is a fallacy that assumes causation from correlation. It comes from the Latin post hoc ergo propter hoc, meaning after this, therefore because of this. The fallacy assumes that because one event followed another, the first caused the second. The rooster crows and the sun rises. The rooster did not cause the sunrise. The sequence is correlation, not causation.

The fallacy is common in superstition. A black cat crosses your path and you have bad luck. The cat did not cause the bad luck. The two events are unrelated. The fallacy is also common in medicine. A patient takes a supplement and feels better. The supplement might have helped. Or the patient might have recovered on their own. The sequence alone does not prove causation.

Post hoc examples

• I wore my lucky socks and we won the game, so the socks caused the win.
• I took a new drug and my headache went away, so the drug worked.
• The economy improved after the tax cut, so the tax cut caused the improvement.
• I ate at that restaurant and got sick, so the restaurant caused my illness.
• The rooster crowed and the sun rose, so the rooster caused the sunrise.

Post hoc is a fallacy of causation. The remedy is to look for evidence of a causal mechanism. Does the supplement have a known biological effect? Is there a controlled study? The sequence is not enough. Correlation is not causation. That is the lesson. The world is full of coincidences. Two events can occur in sequence without being connected. The human mind sees patterns. It sees causes where there are none. Post hoc is a natural error. It takes discipline to avoid. The next time you assume causation from sequence, ask: is there a mechanism? Is there evidence? The answer might be no. The sequence might be a coincidence. The rooster might just be lucky.