Arnold decided to destroy an old warehouse that he owned because the taxes on the structure exceeded the income that he could receive from it. He crept into the building in the middle of the night with a can of gasoline and a fuse and set the fuse timer for 30 minutes. He then left the building. The fuse failed to ignite, and the building was not harmed. Arson is defined in this jurisdiction as "The intentional burning of any building or structure of another, without the consent of the owner." Arnold believed, however, that burning one's own building was arson, having been so advised by his lawyer. Has Arnold committed attempted arson? 
Yes, because factual impossibility is no defense.  Yes, because a mistake of law even on the advice of an attorney is no defense.  No, because his mistake negated a necessary mental state.  No, because even if his actions had every consequence he intended, they would not have constituted arson. 