From Memory Alpha, the free Star Trek reference

[edit] Deleted inaccurate description

I deleted the remark that paradoxes appear true or untrue to common-sense. This may be the case in some paradoxes, but it's not generally true. For example, the real-world Twin Paradox from Special Relativity appears to be contradictory to common-sense, yet it is a physically possible scenario. I do not know of any definition of a paradox given on-screen, so maybe it's best to stick with the real-world definition. --Skon 22:00, 3 September 2006 (UTC)