Atheist who believes in ghosts

If we define atheism as a non-belief or refusal to believe in a god/God then I am certainly an atheist. Dawkins and Hitchens are my bedside reads and like most of you I’m frustrated by people’s gullibility. However (and this is the tricky/potentially embarrassing part) I am open to the existence of what are loosely called ‘ghosts’, for several reasons.