资料来源 : Webster's Revised Unabridged Dictionary (1913)

Non sequitur \Non seq"ui*tur\ [L., it does not follow.] (Logic)
   An inference which does not follow from the premises.

资料来源 : WordNet®

non sequitur
     n 1: a reply that has no relevance to what preceded it
     2: (logic) a conclusion that does not follow from the premises