A fallacious conversion happens when subject and predicate are swapped as if they were equivalent. Not every categorical proposition allows that conversion.
Example
“All communists are atheists”
“Therefore, all atheists are communists”
(The conclusion does not follow.)
Applied example (political)
“All ministers are politicians; therefore all politicians are ministers.” (The swap is invalid.)
Applied example (mystical)
“All healers are spiritual; therefore all spiritual people are healers.” (The conversion is not valid.)
Why it is fallacious
- It changes the logical scope of the statement.
- It confuses inclusion with equivalence.
- It produces a stronger conclusion than the premise.
How to spot it
- Direct subject-predicate swap.
- No proof of equivalence.
- Universal conclusions from one-way premises.
How to respond
- Show that set B can include cases outside A.
- Ask for a proof of equivalence.
- Restate the premise without inverting it.