: In formal logic, a non sequitur is an argument where the conclusion does not follow from the premises. Harry Kim's current life is a "logical leap" that makes no sense based on his actual memories.
In this episode, wakes up in a reality entirely different from the one he knows. Instead of being stranded in the Delta Quadrant aboard the USS Voyager , he finds himself in 24th-century San Francisco.
: It refers to an abrupt or unexpected turn in plot or dialogue. Kim's sudden shift from a starship in deep space to a coffee shop on Earth is a massive, jarring "non sequitur" in his personal narrative. Themes and Impact [S2E5] Non Sequitur
: Like other famous "what if" episodes in the franchise, it allows the audience to see characters in a different light—specifically showing a version of Tom Paris who never found redemption on Voyager .
: The episode poses a classic sci-fi dilemma: should Kim stay in a comfortable, safe life with the woman he loves, or return to a dangerous, stranded existence for the sake of his "true" identity and duty? : In formal logic, a non sequitur is
: Kim's attempts to explain his situation lead Starfleet Security to suspect him of being a Maquis spy. He eventually discovers that a "time-stream" accident involving a shuttlecraft caused him to switch places with his counterpart in this timeline.
You can find more detailed production notes and fan reviews on the Non Sequitur (episode) - Memory Alpha wiki or official series overviews at StarTrek.com. Instead of being stranded in the Delta Quadrant
The title works on multiple levels, drawing from both logic and literature: