a non sequitur

non sequitur

A statement that does not logically fit into the current conversation. Good luck getting answers from him—his every response to my questions so far has been a non sequitur. A: "I changed the oil in the car." B: "Well, that's a complete non sequitur, since I asked if you were hungry!"
See also: non, sequitur

a ˌnon ˈsequitur

(from Latin, formal) a statement that does not seem to follow what has just been said in any natural or logical way: In the middle of a discussion about the weather, Liz started talking about fish. Everyone ignored the non sequitur completely.
The Latin phrase means ‘it does not follow’.
See also: non, sequitur
References in periodicals archive ?
A non sequitur is an inference or conclusion that does not follow from the premise, or a comment unrelated to the preceding one.
In other words, a non sequitur is the essence of illogic.
Non Sequitur" will be horizontal April 30 and vertical May 7, but that's not a non sequitur.
And the idea that employment "of the affected workers" will not suffer because the affected wages are only a small part of costs is a non sequitur at best.
To say, as Senator Joseph Biden did the day before Harkin's speech, that "a hands-off policy would be equally, if not more, likely to lead to war" is not a non sequitur so much as a means of having it both ways.