I'll occasionally post a paradox or puzzling case on a Friday. Today's is an old one--4th century B.C. It's from Eubulides.
The Horn Paradox:
(1) You don't have horns.
(2) If you have not lost something, you still have it.
(3) You have not lost any horns.
(4) Therefore, you (still) have horns. (This follows from (2) and (3))
(5) But (4) contradicts (1) and so we're saddled with a paradox.
If you think you've got a solution to the paradox, please share it with the rest of us by making a comment to this post.