Historian's Fallacy
The historian’s fallacy judges a past decision as though the decision-maker had information learned only later. Assess the choice using what was known, or reasonably knowable, at the time.
THE IDEA
Description
Judging a person's decision in the light of new information not available at the time.
Logical Form
[Person A] made decision X based on information available at the time. [Person B] criticizes [Person A] for not making decision Y based on information that was not available at the time.
Examples
Example #1
Someone avoids the main road because it is usually busy, taking an alternate route. Later, they learn that the alternate route had an unforeseen accident that caused a major delay. A friend says, "You should have taken the main road!" The fallacy lies in judging the decision with knowledge of the accident, which was unavailable at the time.
Example #2
When evaluating Judas Iscariot’s betrayal of Jesus, distinguish a judgment about the act from a claim that he should have foreseen every later consequence. The latter requires evidence about what he could know at the time. Moral criticism of the act is not automatically an instance of the historian’s fallacy.
Exception
Sometimes, it’s funny to purposely commit this fallacy at the expense of your friends’ dignity.
When to use it
Evaluating historical figures' decisions in light of the information they had at the time.
Critiquing a colleague's past business decision without considering the market conditions then.
Analyzing a sports play call after the game, forgetting the uncertainty during the play.
Judging a friend's choice in a game or competition using outcomes they couldn't have known.
FROM THEORY TO EVERYDAY LIFE
In practice
Alternative Route
Someone avoids the main road because it is usually busy, taking an alternate route. Later, they learn that the alternate route had an unforeseen accident that caused a major delay. A friend says, "You should have taken the main road!" This is the historian's fallacy because the friend judges the decision with knowledge of the accident, which was unavailable at the time.
Blame on Judas
A judgment about Judas’s betrayal is different from assuming he should have predicted the subsequent history of Christianity. The historian’s fallacy arises when later knowledge is projected onto his decision, not merely when the act is criticized.
A MOMENT TO REFLECT
Put it to work.
Think of a time when you criticized someone's decision with the benefit of hindsight. How might the situation have looked from their perspective?
Why is it important to consider the information available at the time of a decision when evaluating its quality?
How can the historian's fallacy affect our interpretation of historical events and figures?
CONTINUE THE CONVERSATION
Source texts
- Logically Fallacious - The Ultimate Collection of Over 300 Logical Fallacies