If we accept that ‘interesting’ means ‘would draw interest from a normal, human observer by some intrinsic or displayed quality’, then there can never be a Least Interesting Man In The World.
Take the individual from the original xkcd. Let’s say that all his character flaws and uninteresting habits—his general dullness, in other words—have led to him being named the LIMIT (omitting the W to make the acronym look better). Immediately upon being named the LIMIT, he would become a curiosity in his own right (based on the conjecture that advertising anything as the extreme end of a spectrum—worst person in the world, best maple syrup in Vermont, etc—causes interest in that thing) and thus no longer be the LIMIT. And as soon as he stops being the LIMIT, he would lose the added interest of his position as the LIMIT, and instantly become the LIMIT again, and lose it, again. He is a walking paradox, and can never remain stable long enough to enjoy his title as the LIMIT.
|Unlike, say, this fellow.|
Or, and this is my favorite, we could assume that the least interesting man in the world is forced into this paradox involving the title of LIMIT, and that he would be effectively unobservable from there on. In other words, the LIMIT would be trapped in a kind of singularity of interestingness and uninterestingness. Since he would switch roles as many times a second as he could be observed, the case could be made that no one would be able to observe the effects of the paradox. The title of LIMIT--call this one LIMIT-B—would then pass to the second least interesting man in the world, who would ascend to the top spot by virtue of his predecessor’s descent into unobservability. It’s an open question as to whether the paradox would claim him as well, or whether he would simply acknowledged as being as close to the LIMIT as man can get while still remaining visible.
|Alternatively, the entire issue might just vanish into a black hole.|