modus ponens

[ moh-duhs poh-nenz ]

noun

, Logic.

, plural mo·dus po·nen·tes [moh, -d, uh, s poh-, nen, -teez].

1. the reasoning that, when a conditional statement is accepted as true, as “ If X is red, then Y is blue,” it can be inferred when the antecedent is known to be true, as “X is red,” that its consequent, “Y is blue,” is affirmed.
2. an argument based on the reasoning of modus ponens:

   A simple modus ponens might begin with “If Joe sneezes, Tom laughs.”

modus ponens

/ ˈməʊdəs ˈpəʊˌnɛnz /

noun

1. logic the principle that whenever a conditional statement and its antecedent are given to be true its consequent may be validly inferred, as in if it's Tuesday this must be Belgium and it's Tuesday so this must be Belgium

Word History and Origins

Origin of modus ponens¹

First recorded in 1835–40; New Latin: literally “affirming mode”

Word History and Origins

Origin of modus ponens¹

literally: mood that affirms

Example Sentences

It consisted primarily of modus ponens—“If A is true, then B is true. A is true. Therefore, B is true”—and modus tollens—“If A is true, then B is true. B is not true. Therefore, A is not true.”

From Scientific American

“Modus ponens is O.K. when you’re doing the informal proofs, but modus tollens can be tough,” Murphy said as he packed his books and pens.

From New York Times

Instead, all their arguments involve what logicians know as “modus ponens”: that if X implies Y and X is true, then Y must also be true.

From Scientific American

This is the Modus Ponens or Positive Mode, where you reach a conclusion by obtaining the admission of the Antecedent.

From Project Gutenberg

Two Moods are usually recognised the Modus ponens, in which the antecedent of the hypothetical major premise is affirmed; and the Modus tollens, in which its consequent is denied.

From Project Gutenberg