Jim, such problems may indeed occur in legal practice. I also thought that Jack might be a minister who has just pronounced "I now pronounce you husband" at that moment, thus George is already Anne's husband, but Anne will not be married until "... and wife".

However, we may say that the riddle we implicitly assumes a definite notion of "married" and "look at". Moreover, both notions should be assumed decidable (i.e. it can be found out safely whether Anne is married).

Also, Jack and Anne must be beings capable of looking at something. Jack is in fact married, thus presumably a person.

If we now say "unmarried" means "not a currently married person", George may be yet another dog, or a statue (like "my Oscar") etc. If however we declare that "unmarried" can only be said of persons, which sounds reasonable, we can say that both Jack and George are persons. Anne is still only known to be a being capable of looking, which is certainly not the same as a person. She may be an octopus or whatever.

For the solution as given above, the riddle would need at least two further premises: 1. Anne is a person, 2. "unmarried" is used as a synonym of "not married". It would be better still if they either mentioned that "unmarried" can only be said of persons, or explicitly say that George is a person.

McGrath, consider someone offers on eBay an "unused postage stamp" and then says "it was used formerly, but currently it's unused".