Lucien is 99.9% sure ghosts don't exist. This, Lucien has decided, is not actually sure enough to justify not even bothering to check. Sure, believing in ghosts is embarrassing and there's no concrete evidence but.... it's really a startingly common belief. Across places and times too - ghost stories are found in cultures as unrelated as the Aztecs and Egyptians. The existence and timing of Halloween is a well known cultural universal. 

So, Lucien is going to check. Even if it feels deeply silly to trek out on a moonless night to the supposedly haunted house near his grandparents' place.