This fallacy occurs when the speaker concludes that one event was caused by another simply because it happened after it, without providing sufficient evidence of a causal relationship.
Definition:
Post hoc ergo propter hoc is a reasoning error in which the chronological order of two events is mistakenly interpreted as a cause-and-effect relationship. This fallacy typically occurs when the only reason given to prove causation is that the second event followed the first, whereas temporal correlation alone is not sufficient to establish causality.
Typical structure of this fallacy:
1. Event A occurred before event B.
2. Therefore, A caused B.
Examples from real life:
1. Politics:
“Since this party came to power, unemployment has fallen. Therefore, this party has caused a reduction in unemployment.”
Here, it should be noted that other factors, such as global economic conditions or previous policies, may have contributed to the decrease.
2. Medicine:
“After taking this herbal remedy, my cold got better. Therefore, the remedy cured me.”
Here, it should be noted that the recovery may have occurred naturally without any effect from the remedy.
3. Sport:
“Since the players changed the colour of their kit, the team has won three matches in a row. Therefore, the change of kit colour has caused these victories.”
Here, it should be noted that consecutive wins may be due to other factors such as improved tactics, the players’ physical fitness, or the weakness of their opponents, and that a change of kit colour cannot be a logical cause of this success.
4. Everyday life:
“Every time I wear this shirt, I have a good day. Therefore, this shirt brings me luck.”
Here, it should be noted that this belief is based on superstition and lacks real evidence.
Why is this fallacy dangerous?
● It can lead to decisions based on false assumptions.
● It obscures the real cause-and-effect relationships.
● It encourages the development of superstitious and unfounded beliefs.
How can we recognise and respond to it?
Ask:
– Is there any evidence beyond the chronological order to support a causal link?
– Could both events be the result of a common factor?
– Is the relationship merely a coincidental correlation?
A suitable response might be: “Just because event B followed event A does not mean A caused B. Let’s find more evidence for this claim.”
Conclusion:
The post hoc ergo propter hoc fallacy, by relying solely on temporal sequence, distorts cause-and-effect relationships and leads to incorrect conclusions. To gain an accurate understanding of events, independent evidence and careful analysis are necessary to avoid falling into the trap of false correlation.