🌐EnglishEnglishBahasa IndonesiaDeutschEspañolFrançaisItalianoNederlandsPolskiPortuguêsSvenskaTürkçeРусскийفارسی한국어中文日本語EntityQ844118· pop 28· linked from 105 articlesmodus tollensAlso known as modus tollendo tollens, MTif X implies Y, and Y isn't true, then neither is XAvailable in 28 languagesEspañolFrançaisDeutsch中文日本語РусскийPortuguêsItalianoBahasa IndonesiaBasqueCatalanConnectionscontrapositionEntityreductio ad absurdumEntityCategoriesClassical logicLatin logical phrasesRules of inferenceTheorems in propositional logic