Corollary

“Corollary (noun): An assertion or proposition that follows implicitly, with little or no proof, from a given statement; an immediate deduction or inference; natural consequence, parallel, or accompaniment. Adjective: corollary

‘If this book doesn’t make you angry, it wasn’t worth writing.’ As any logician can tell you, the corollary of the above quotation is not necessarily true, that is, if the book does make you angry, it does not necessarily follow that it was worth writing. Laurence Urdang, Verbatim“

Excerpted from: Grambs, David. The Random House Dictionary for Writers and Readers. New York: Random House, 1990.