Modal logic studies ways in which propositions can be true or false, the most common being necessity and possibility . Some propositions are necessarily true/false, and others are possibly true/false.
Examples:
- _If Debbie and TJ have two sons and two daughters, then they must have at least one son.
Debbie and TJ have two sons and two daughters.
Therefore, Debbie and TJ must have at least one son._
Synonyms: fallacy of modal logic, misconditionalization, fallacy of necessity