No one can prove a negative. You can't prove the non-existance of the Invisible Pink Unicorn, the Flying Speghetti Monster, or Bertrand Russell's  Celestial Teapot, much less the existance of Zeus, Santa Klaus, gobblins, the Easter Bunny, gnomes, faeries, vampires, werewolves, or zombies. Since you can't prove they don't exist, do you assume they do?