1) The Cardinals come from behind and go from a 0-3 deficit to win the World Series.

This will prove one of two things:
1) The Boston Red Sox really are cursed.
2) Anything really can happen in the postseason.

Which one it proves depends upon whether you really believe in curses or not.

2) The Boston Red Sox win.

This will prove only one thing:
1) The Boston Red Sox aren’t cursed.
— Whether they were and the curse is over, or if they never were, depends on your view of curses.