IDEA FOUND // IDEA 113
Affirming the Consequent
“Seeing the expected result does not automatically identify what produced it.”
01 / PLAINLY
What it means, plainly
Affirming the consequent means concluding A just because B appeared in an ‘if A, then B’ rule. It overlooks other ways B might happen.
02 / CONTEXT
A little more
The invalid form is: if A, then B; B; therefore A. B may have several causes, so its presence does not guarantee A.
03 / WHY IT MATTERS
Why it matters
Catching the error keeps a possible explanation from being mistaken for a proven cause when reading symptoms, failures, or coincidences.
04 / EXAMPLE
A familiar example
If it rains, the street gets wet. The street is wet. Rain does not follow; a cleaning truck may have passed.
05 / LIMIT
What it does not mean
An explanation compatible with the observation is not yet the only explanation or a proven cause.
06 / NOTICE
Notice it in your day
Pick an everyday result, such as a blank screen. List three possible causes before deciding what happened.
FINAL NOTE
The idea worth keeping
When B appears, look for other routes that could have produced it.
QUESTIONS / 02
Questions people still have
Why is moving from B back to A invalid?
Because causes other than A may also produce B.
What should you do after seeing the expected result?
Consider other compatible explanations before assigning a cause.