Legal Theory Blog explains it all for you:
The reason why analytic philosophers (and similarly mathematicians and cognitive scientists) have a difficult time dressing themselves or dress poorly is that the satisfaction of any sentence involving the "goes with" relation is not finitely decidable. There is no algorithm by which one can in a finite amount of time, much less in the morning before you are too late for class, decide with deductive certainty whether an outfit is sharp and properly accessorized. Now, there are rules which by which we can rule out entire classes of ordered pairs, e.g., let x be a member of the class of checked clothing and y be a member of the class of striped clothing, it is fairly trivial to show that for all such x and all such y, Gxy must be false (I leave it as an exercise to the reader to provide a proof). But for the general case there is no finitely executable decision procedure such that for any two arbitrary articles of clothing one may determine the satisfaction of G.
(Hat tip: Harry.)