Sound of Silence | RP. Innocent Ino, O. CarmPrinciples of philosophical logic
Ab esse ad posse valet, a posse ad esse non valet (consequentia) (also ab esse a posse principle) is a basic tenet of philosophical logic. It states that possibility (from being able to) can be inferred from reality. But any other way of inferring reality from possibility is invalid.
The logical rule expresses modal consequences: " Quod existit, id est possibile " (Chr. WOLF, Ont. § 170). From assertion validity (Latin assertio 'statement') follows problematic judgment, but not vice versa.
