Suppose a man, Frank, weighs 250 lbs. To some extent, whether or not we count Frank as fat will depend on context. If Frank stands only 5'3" then we might say he's fat; however, if Frank is 7'4" then quite clearly he is not fat. There are, of course, other factors to consider, too (e.g. muscle mass). With that said, it seems to me that we can tweak his height, muscle mass, etc., to the point where it's simply unclear whether Frank should count as fat or not, and neither empirical examination nor rigorous conceptual analysis will clear up the matter. There is ultimately a problem with our very notion of what it is to be fat--and there are many, many other similar cases of vagueness in our language. Does this inherent vagueness imply that there is no fact of the matter about whether Frank is fat? What about the cases where it seems so intuitively clear that Frank is fat (e.g. in possible worlds where he's only 5'3")?