A Fortiori (understood Ratione)

A FORTIORI (understood: ratione). — With even greater reason. One of the forms of the argument from analogy. It occurs when, from a certain assertion x, one concludes to an assertion y, because the reason that applies to x applies, or seems to apply, even more strongly to y. E.g.: Titius is very generous in charitable works; therefore, a f., he will be honest in his contracts. The a f. argument, although it may yield a certain conclusion, remains problematic in its logical structure, since it is based essentially on a relationship of resemblance, which by itself is not a sufficient guarantee of certainty.